on newly installed equipment to obtain actual indicators and draw up standard characteristics;
periodically during operation (at least 1 time in 3-4 years) to confirm compliance with regulatory characteristics.
Based on the actual indicators obtained in the process of thermal testing, the ND on fuel use is compiled and approved, the validity period of which is set depending on the degree of its development and the reliability of the source materials, the planned reconstructions and upgrades, equipment repairs, but cannot exceed 5 years.
Based on this, full thermal tests to confirm the compliance of the actual characteristics of the equipment with the regulatory ones should be carried out by specialized commissioning organizations at least once every 3-4 years (taking into account the time required to process the test results, confirm or revise the RD).
By comparing the data obtained as a result of testing to assess the energy efficiency of a turbine plant (the maximum achievable electric power with the corresponding specific heat consumption for generating electricity in condensing and controlled extraction modes with a calculated thermal scheme and with nominal parameters and conditions, the maximum achievable steam and heat supply for turbines with controlled bleeds, etc.), an expert organization on fuel use issues a decision to confirm or revise the RD.

List
used literature to chapter 4.4
1. GOST 24278-89. Stationary steam turbine plants for driving electric generators at TPPs. General technical requirements.
2. GOST 28969-91. Stationary steam turbines of low power. General technical requirements.
3. GOST 25364-97. Stationary steam turbine units. Vibration standards for shafting supports and general requirements for measurements.
4. GOST 28757-90. Heaters for the regeneration system of steam turbines of thermal power plants. General specifications.
5. Collection of administrative documents for the operation of energy systems (Heat engineering part) .- M .: CJSC Energoservice, 1998.
6. Guidelines for the verification and testing of automatic control systems and protection of steam turbines: RD 34.30.310.- M .:
SPO Soyuztekhenergo, 1984. (SO 153-34.30.310).
Amendment to RD 34.30.310. – M.: SPO ORGRES, 1997.
7. Typical operating instructions for oil systems of turbine plants with a capacity of 100-800 MW, operating on mineral oil: RD 34.30.508-93.- M .: SPO ORGRES, 1994.
(SO 34.30.508-93).
8. Guidelines for the operation of condensing units of steam turbines of power plants: MU 34-70-122-85 (RD 34.30.501).-
M.: SPO Soyuztekhenergo, 1986. (SO 34.30.501).
9. Typical operating instructions for systems
regeneration of high pressure power units with a capacity of 100-800 MW; RD 34.40.509-93, - M.: SPO ORGRES, 1994. (SO 34.40.509-93).
10. Typical instruction for operation of the condensate path and low-pressure regeneration system of power units with a capacity of 100-800 MW at CHP and KES: RD 34.40.510-93, - M .: SPO ORGRES, 1995. (SO 34.40.510-93).
P. Golodnova O.S. Operation of oil supply systems and seals of turbogenerators with; hydrogen cooling. - M.: Energy, 1978.
12. Typical operating instructions for the gas-oil system for hydrogen cooling of generators: RD 153-34.0-45.512-97.- M .: SPO ORGRES,
1998. (SO 34.45.512-97).
13. Guidelines for the conservation of thermal power equipment: RD 34.20,591-97. -
M.: SPO ORGRES, 1997. (SO 34.20.591-97).
14. Regulation on the regulation of fuel consumption at power plants: RD 153-34.0-09.154-99. – M.:
SPO ORGRES, 1999. (SO 153-34.09.154-99).

Thermal testing of steam turbines
and turbine equipment

In recent years, in the line of energy saving, attention has increased to fuel consumption standards for enterprises generating heat and electricity, therefore, for generating enterprises, the actual efficiency indicators of heat and power equipment are becoming important.

At the same time, it is known that the actual efficiency indicators under operating conditions differ from the calculated (factory), therefore, in order to objectively standardize fuel consumption for the generation of heat and electricity, it is advisable to test the equipment.

On the basis of equipment test materials, normative energy characteristics and a layout (order, algorithm) for calculating the norms of specific fuel consumption are developed in accordance with RD 34.09.155-93 "Guidelines for the compilation and maintenance of energy characteristics of thermal power plant equipment" and RD 153-34.0-09.154 -99 "Regulations on the regulation of fuel consumption at power plants."

Of particular importance is the testing of heat and power equipment for facilities operating equipment put into operation before the 70s and where modernization and reconstruction of boilers, turbines, auxiliary equipment was carried out. Without testing, normalization of fuel consumption according to the calculated data will lead to significant errors not in favor of generating enterprises. Therefore, the costs of thermal testing are negligible compared to the benefits.

The objectives of thermal testing of steam turbines and turbine equipment: determination of actual economy; obtaining thermal characteristics; comparison with manufacturer's warranties; obtaining data for standardization, control, analysis and optimization of turbine equipment operation; obtaining materials for the development of energy characteristics; development of measures to improve efficiency

The objectives of express testing of steam turbines: determination of the feasibility and scope of repairs; assessment of the quality and effectiveness of the repair or modernization; assessment of the current change in the efficiency of the turbine during operation.

Modern technologies and the level of engineering knowledge make it possible to economically upgrade units, improve their performance and increase their service life.

The main goals of modernization are:

reduction of power consumption of the compressor unit;

increase in compressor performance;

increasing the power and efficiency of the process turbine;

reduction of natural gas consumption;

increasing the operational stability of equipment;

reducing the number of parts by increasing the pressure of compressors and operating turbines at a smaller number of stages while maintaining and even increasing the efficiency of the power plant.

The improvement of the given energy and economic indicators of the turbine unit is carried out through the use of modernized design methods (solution of the direct and inverse problems). They are related:

with the inclusion of more correct models of turbulent viscosity in the calculation scheme,

taking into account the profile and end blockage by the boundary layer,

elimination of separation phenomena with an increase in the diffuseness of the interblade channels and a change in the degree of reactivity (pronounced non-stationarity of the flow before the occurrence of surge),

the possibility of identifying an object using mathematical models with genetic optimization of parameters.

The ultimate goal of modernization is always to increase the production of the final product and minimize costs.

An integrated approach to the modernization of turbine equipment

When carrying out modernization, Astronit usually uses an integrated approach, in which the following components of the technological turbine unit are reconstructed (modernized):

compressor;

• centrifugal compressor-supercharger;

  intercoolers;

  multiplier;

  Lubrication system;

  air cleaning system;

  automatic control and protection system.

Modernization of compressor equipment

The main areas of modernization practiced by Astronit specialists:

replacement of flow parts with new ones (the so-called replaceable flow parts, including impellers and vaned diffusers), with improved characteristics, but in the dimensions of existing housings;

reduction in the number of stages due to the improvement of the flow path based on three-dimensional analysis in modern software products;

application of easy-to-work coatings and reduction of radial clearances;

replacement of seals with more efficient ones;

replacement of compressor oil bearings with "dry" bearings using magnetic suspension. This eliminates the use of oil and improves the operating conditions of the compressor.

Implementation of modern control and protection systems

To improve operational reliability and efficiency, modern instrumentation, digital automatic control and protection systems (both individual parts and the entire technological complex as a whole), diagnostic systems and communication systems are being introduced.

STEAM TURBINES

Nozzles and blades.

Thermal cycles.

Rankine cycle.

Reheat cycle.

Cycle with intermediate extraction and utilization of exhaust steam heat.

Turbine structures.

Application.

OTHER TURBINES

Hydraulic turbines.

gas turbines.

Scroll upScroll down

Also on topic

AIRCRAFT POWER PLANTS

ELECTRIC ENERGY

SHIP POWER PLANTS AND PROPULSIONS

HYDROPOWER

TURBINE

TURBINE, prime mover with rotational movement of the working body for converting the kinetic energy of the flow of a liquid or gaseous working fluid into mechanical energy on the shaft. The turbine consists of a rotor with blades (bladed impeller) and a casing with nozzles. Branch pipes bring in and divert the flow of the working fluid. Turbines, depending on the working fluid used, are hydraulic, steam and gas. Depending on the average direction of flow through the turbine, they are divided into axial, in which the flow is parallel to the axis of the turbine, and radial, in which the flow is directed from the periphery to the center.

STEAM TURBINES

The main elements of a steam turbine are the casing, nozzles and rotor blades. Steam from an external source is supplied to the turbine through pipelines. In the nozzles, the potential energy of the steam is converted into the kinetic energy of the jet. The steam escaping from the nozzles is directed to curved (specially profiled) working blades located along the periphery of the rotor. Under the action of a jet of steam, a tangential (circumferential) force appears, causing the rotor to rotate.

Nozzles and blades.

Steam under pressure enters one or more fixed nozzles, in which it expands and from where it flows out at high speed. The flow exits the nozzles at an angle to the plane of rotation of the rotor blades. In some designs, the nozzles are formed by a series of fixed blades (nozzle apparatus). The vanes of the impeller are curved in the direction of flow and arranged radially. In an active turbine (Fig. 1, a) the flow channel of the impeller has a constant cross section, i.e. the speed in relative motion in the impeller does not change in absolute value. The steam pressure in front of the impeller and behind it is the same. In a jet turbine (Fig. 1, b) flow channels of the impeller have a variable cross section. The flow channels of a jet turbine are designed so that the flow rate in them increases, and the pressure decreases accordingly.

R1; c - blading the impeller. V1 is the steam velocity at the outlet of the nozzle; V2 is the speed of steam behind the impeller in a fixed coordinate system; U1 – peripheral speed of the blade; R1 is the speed of steam at the impeller inlet in relative motion; R2 is the speed of steam at the outlet of the impeller in relative motion. 1 - bandage; 2 - scapula; 3 – rotor." title="(!LANG:Fig. 1. TURBINE BLADES. a - active impeller, R1 = R2; b - jet impeller, R2 > R1; c - impeller blades. V1 - steam speed at the nozzle outlet; V2 is the steam velocity behind the impeller in a fixed coordinate system; U1 is the circumferential velocity of the blade; R1 is the steam velocity at the impeller inlet in relative motion; R2 is the steam velocity at the impeller outlet in relative motion. 1 - bandage; 2 - blade; 3 - rotor.">Рис. 1. РАБОЧИЕ ЛОПАТКИ ТУРБИНЫ. а – активное рабочее колесо, R1 = R2; б – реактивное рабочее колесо, R2 > R1; в – облопачивание рабочего колеса. V1 – скорость пара на выходе из сопла; V2 – скорость пара за рабочим колесом в неподвижной системе координат; U1 – окружная скорость лопатки; R1 – скорость пара на входе в рабочее колесо в относительном движении; R2 – скорость пара на выходе из рабочего колеса в относительном движении. 1 – бандаж; 2 – лопатка; 3 – ротор.!}

Turbines are usually designed to be on the same shaft as the device that consumes their energy. The speed of rotation of the impeller is limited by the tensile strength of the materials from which the disk and blades are made. For the most complete and efficient conversion of steam energy, turbines are made multi-stage.

Thermal cycles.

Rankine cycle.

In a turbine operating according to the Rankine cycle (Fig. 2, a), steam comes from an external steam source; there is no additional steam heating between the turbine stages, there are only natural heat losses.

Reheat cycle.

In this cycle (Fig. 2, b) steam after the first stages is sent to the heat exchanger for additional heating (overheating). Then it returns to the turbine again, where its final expansion takes place in subsequent stages. Increasing the temperature of the working fluid allows you to increase the efficiency of the turbine.

Rice. 2. TURBINES WITH DIFFERENT HEAT CYCLES. a – simple Rankine cycle; b – cycle with intermediate steam heating; c - cycle with intermediate steam extraction and heat recovery.

Cycle with intermediate extraction and utilization of exhaust steam heat.

The steam at the outlet of the turbine still has significant thermal energy, which is usually dissipated in the condenser. Part of the energy can be taken from the condensation of the exhaust steam. Some part of the steam can be taken from the intermediate stages of the turbine (Fig. 2, in) and is used for preheating, for example, feed water or for any technological processes.

Turbine structures.

The working medium expands in the turbine, so the last stages (low pressure) must have a larger diameter in order to pass the increased volume flow. The increase in diameter is limited by the allowable maximum stresses due to centrifugal loads at elevated temperatures. In split-flow turbines (Figure 3), the steam passes through different turbines or different turbine stages.

Rice. 3. TURBINES WITH FLOW BRANCHING. a - double parallel turbine; b – double turbine of parallel action with oppositely directed flows; c – turbine with flow branching after several stages of high pressure; d - compound turbine.

Application.

To ensure high efficiency, the turbine must rotate at high speed, but the number of revolutions is limited by the strength of the materials of the turbine and the equipment that is on the same shaft with it. Electric generators in thermal power plants are rated at 1800 or 3600 rpm and are usually installed on the same shaft as the turbine. Centrifugal superchargers and pumps, fans and centrifuges can be installed on the same shaft with the turbine.

The low speed equipment is coupled to the high speed turbine via a reduction gear, such as in marine engines where the propeller must rotate at 60 to 400 rpm.

OTHER TURBINES

Hydraulic turbines.

In modern hydraulic turbines, the impeller rotates in a special housing with a volute (radial turbine) or has a guide vane at the inlet to ensure the desired flow direction. The appropriate equipment is usually installed on the shaft of a hydroturbine (an electric generator at a hydroelectric power station).

gas turbines.

The gas turbine uses the energy of gaseous combustion products from an external source. Gas turbines are similar in design and principle of operation to steam turbines and are widely used in engineering. see also AIRCRAFT POWER PLANTS; ELECTRIC ENERGY; SHIP POWER PLANTS AND PROPULSIONS; HYDROPOWER.

Literature

Uvarov V.V. Gas turbines and gas turbine plants. M., 1970
Verete A.G., Delving A.K. Marine steam power plants and gas turbines. M., 1982 equipment: basic (boiler plants and steam turbines) and auxiliary. For powerful turbines(And it's about...

Thermal trial gas turbine plant

Laboratory work >> Physics

UPI "Department" Turbines and engines "Laboratory work No. 1" Thermal trial gas turbine plant" Option ... as part of the complex equipment the test stand was turned on ... the launcher was applied steam turbine built on the basis...

Choice of diaphragm blade welding method steam turbines (2)

Coursework >> Industry, production

Melting using thermal energy (arc, ... details steam turbines. shoulder blades steam turbines subdivided... – manufacturability, – availability of the necessary equipment, – availability of qualified personnel, – ... with relevant trials. Thereafter...

thermal power unit scheme

Diploma work >> Physics

... test; ... equipment thermal power plants. – M.: Energoatomizdat, 1995. Ryzhkin V.Ya. Thermal... power plants. – M.: Energoatomizdat, 1987. Shklover G.G., Milman O.O. Research and calculation of condensing devices steam turbines ...

This CMEA standard applies to stationary steam turbines for driving turbine generators of power plants and establishes the basic rules for the acceptance of turbines and auxiliary equipment during and after installation and testing.

1. GENERAL PROVISIONS

1.1. During the acceptance of the turbine, quality control of the installation is carried out in order to ensure reliable and uninterrupted operation of the turbine and auxiliary equipment during operation. At the same time, control is also exercised over the fulfillment of labor protection, safety and fire safety requirements.

The basic rules for the installation of turbines are given in the information appendix.

1.2. Acceptance of the turbine into operation should consist of the following stages:

1) checking the completeness and technical condition of the turbine and auxiliary equipment before assembly and installation;

2) acceptance of assembly units and turbine systems after installation work;

3) acceptance of assembly units and systems of the steam turbine unit based on the results of their testing;

4) acceptance of the turbine based on the results of comprehensive tests of the steam turbine unit (power unit).

2. ACCEPTANCE OF ASSEMBLY UNITS AND SYSTEMS

2.1. Checking the completeness and technical condition of the turbine assembly units and auxiliary equipment should be carried out as the equipment arrives for installation.

At the same time, the absence of damage and defects of the equipment, the preservation of color, preservative and special coatings, and the integrity of seals are checked.

2.2. Each mechanism, apparatus and system of the steam turbine unit after assembly and installation must pass the tests provided for in the technical documentation. If necessary, an audit can be carried out with the elimination of identified defects.

2.3. The acceptance program shall include the tests and checks necessary to ensure the reliable operation of the steam turbine unit, including:

1) checking the tightness of stop and control valves;

2) verification of the correctness of the readings of measuring instruments, blocking and protection of the unit's systems;

3) checking the correct operation and preliminary adjustment of the regulators of the unit's systems;

9) checking the operation of the regeneration system;

10) checking the density of the vacuum system of the unit.

3. ACCEPTANCE OF THE TURBINE FOR OPERATION

3.1. The final stage of acceptance of the turbine into operation should be a comprehensive test for 72 h when operating for its intended purpose and at nominal electrical and thermal loads.

If, under the conditions of operation of the power plant, the rated loads cannot be achieved, the steam turbine set should be accepted according to the results of tests at the maximum possible load.

3.2. The criterion for acceptance of the turbine into operation should be the absence within the specified time of complex testing of defects that prevent long-term operation.

If, according to the operating conditions of the power plant, complex tests cannot continue for the specified time, the turbine is considered to have passed the tests if there are no defects during the actual time of the complex tests.

3.3. Acceptance of the turbine for operation must be confirmed by a corresponding entry in the form or passport for the turbine in accordance with ST SEV 1798-79.

INFORMATION APPENDIX

BASIC RULES FOR INSTALLATION OF TURBINES

1. The machine room and foundations must be freed from formwork, scaffolding and cleared of debris. Openings must be fenced, and channels, trays and hatches must be closed.

2. In preparation for installation work in winter conditions, windows should be glazed, doorways closed, and heating of the engine room and structures in which a temperature of at least +5 ° C is required for the installation of turbine equipment should be put into operation.

3. On the foundations handed over for the installation of equipment, marking axes for the main equipment must be applied and elevation marks must be fixed.

4. On the foundations intended for the installation of the turbine, the axles must be applied to the embedded metal parts, and the elevation marks must be fixed on the benchmarks.

The axes and benchmarks fixed on the foundation must be located outside the contour of the foundation frames and other supporting structures. Deviations from the design dimensions should not exceed the values ​​established by the supplier in the technical documentation for the production and acceptance of work on the construction of concrete, reinforced concrete and metal structures of foundations.

5. When performing installation work, the requirements of instructions and rules for labor protection and safety must be observed.

6. During installation, the equipment must be cleaned of preservative lubricants and coatings, with the exception of surfaces that must remain covered with protective compounds during the operation of the equipment. Protective coatings on the internal surfaces of the equipment should be removed, as a rule, without dismantling the equipment.

7. Immediately before installing the equipment, the foundation bearing surface must be cleaned to clean concrete and washed with water.

8. Equipment having machined bearing surfaces should be installed on precisely calibrated rigid bearing surfaces of the foundation surface.

9. During the installation process, the bench assembly of the turbine must be repeated in compliance with the clearances, centering of mating assembly units in accordance with the passports and technical requirements.

10. Deviations from the design binding dimensions and marks, as well as from horizontal, vertical, coaxiality and parallelism during installation of equipment should not exceed the allowable values ​​specified in the technical documentation and installation instructions for individual types of equipment.

11. During the installation of equipment, the quality control of the work performed, provided for in the technical documentation, must be carried out.

Identified defects must be eliminated before the next installation operations.

12. Concealed work performed during the installation process is checked to determine whether their performance meets the technical requirements. Hidden include work on assembling machines and their assembly units, checking clearances, tolerances and fits, aligning equipment and other work if their quality cannot be verified after subsequent installation or construction work.

13. The equipment supplied for installation should not be disassembled, except when its disassembly during installation is provided for by the technical conditions, instructions or technical documentation.

14. Pipelines and heat exchangers of the steam turbine unit systems must be delivered to the installation site cleaned and mothballed.

2. Subject - 17.131.02.2-76.

3. The CMEA standard was approved at the 53rd meeting of the PCC .

4. Dates for the start of application of the CMEA standard:

5. The term of the first inspection is 1990, the frequency of inspection is 10 years.

The main objectives of the tests are to assess the actual state of the turbine plant and its components; comparison with the manufacturer's guarantees and obtaining the data necessary for planning and standardizing its work; optimization of modes and implementation of periodic monitoring of the efficiency of its work with the issuance of recommendations to improve efficiency.

Depending on the objectives of the work, the total scope of tests and measurements, as well as the types of instruments used, are determined. So, for example, tests according to category I of complexity (such tests are also called "balance" or complete tests) of head samples of turbines, turbines after reconstruction (modernization), as well as turbines that do not have a typical energy characteristic, require a large amount of measurements of an increased accuracy class with the obligatory balancing the main steam and water consumption.

Based on the results of several tests of turbines of the same type in the 1st category of complexity, typical energy characteristics are developed, the data of which are taken as the basis for determining the normative indicators of equipment.

With all other types of tests (according to the II category of complexity), as a rule, particular tasks are solved, associated, for example, with determining the efficiency of repairing a turbine plant or upgrading its individual components, periodic monitoring of the state during the overhaul period, experimental finding of some correction dependences for the deviation of parameters from nominal, etc. Such tests require a much smaller volume of measurements and allow the widespread use of standard instruments with their mandatory verification before and after testing; in this case, the thermal scheme of the turbine plant should be as close as possible to the design one. Processing of test results for the II category of complexity is carried out according to the method of "constant flow rate of live steam" (see section E.6.2) using correction curves according to typical energy characteristics or manufacturers.

Along with the above tests, narrower goals can also be pursued, for example, determining the comparative efficiency of regimes with "cut-off LPC" for T-250 / 300-240 turbines, finding corrections to power for changes in exhaust steam pressure in the condenser when operating according to the heat curve, determining losses in the generator, the maximum throughput of the steam inlet and the flow path, etc.

In these Guidelines, the main attention is paid to issues related only to testing turbines in category I of complexity, as representing the greatest difficulty at all stages. The test procedure for the II category of complexity will not present great difficulties after mastering the methodology for testing for the I category of complexity, since tests for the II category of complexity, as a rule, require a much smaller amount of measurements, cover the units and elements of the turbine plant, controlled by the I category of complexity, consist of a small number of experiments that do not require compliance with strict and numerous requirements for the thermal scheme and conditions for their implementation.

B. TEST PROGRAM

B.one. General provisions

After a clear clarification of the goals and objectives of the tests, in order to draw up their technical program, it is necessary to carefully familiarize yourself with the turbine plant and have complete information about:

Condition and its compliance with design data;

Its capabilities in terms of ensuring the flow of live steam and steam of controlled extractions, as well as the electrical load in the required range of their change;

Its ability to maintain during the experiments the parameters of steam and water close to nominal and the constancy of the opening of the steam distribution organs;

Opportunities for its operation under the design thermal scheme, the presence of restrictions and intermediate inlets and outlets of extraneous steam and water and the possibility of their exclusion or, as a last resort, accounting;

Possibilities of the measuring circuit to ensure reliable measurements of parameters and costs in the entire range of their change.

The sources of obtaining this information may be the technical specifications (TS) for the supply of equipment, instructions for its operation, audit reports, lists of defects, analysis of the readings of regular recording devices, personnel interviews, etc.

The test program should be drawn up in such a way that, based on the results of the experiments, the dependencies of both the general efficiency indicators of the turbine plant (live steam and heat flow rates from the electric load and the steam flow rates of controlled extractions) and private indicators characterizing the efficiency can be calculated and plotted in the required range. individual compartments (cylinders) of the turbine and auxiliary equipment (for example, internal efficiency, stage pressures, temperature differences of heaters, etc.).

The general efficiency indicators obtained from the test make it possible to evaluate the level of a turbine plant in comparison with guarantees and data on turbines of the same type, and also serve as the starting material for planning and standardizing its operation. Particular performance indicators, by analyzing them and comparing them with design and regulatory data, help to identify units and elements that work with reduced efficiency, and timely outline measures to eliminate defects.

IN 2. Structure of the test program

The technical test program consists of the following sections:

Test objectives;

List of modes. In this section, for each series of regimes, the flow rates of live steam and steam in controlled extractions, pressures in regulated extractions and electrical load, as well as a brief description of the thermal scheme, the number of experiments and their duration are indicated;

- general test conditions. This section specifies the basic requirements for the thermal scheme, gives the limits for the deviation of steam parameters, the method for ensuring the constancy of the regime, etc.

The test program is agreed with the heads of the workshops: boiler-turbine, adjustment and testing, electrical, PTO and is approved by the chief engineer of the power plant. In some cases, for example, when testing prototype turbines, the program is also agreed with the manufacturer and approved by the chief engineer of the power system.

AT 3. Development of test programs for turbines of various types

B.3.1. Condensing and backpressure turbines

The main characteristics of turbines of this type are the dependences of the flow rate of live steam and heat (total and specific) on the electrical load, so the main part of the test program is devoted to experiments to obtain precisely these dependences. Experiments are carried out with the design thermal scheme and nominal steam parameters in the range of electrical loads from 30-40% of the nominal to maximum.

To be able to build the characteristics of turbines with backpressure in the entire range of change of the latter, either three series of experiments (at maximum, nominal and minimum backpressures), or only one series (at nominal backpressure) and experiments to determine the correction to power for a change in backpressure, are carried out.

The choice of intermediate loads is carried out in such a way as to cover all the characteristic points of dependencies, corresponding, in particular:

The opening times of the control valves;

Switching the power source of the deaerator;

Switching from a feed electric pump to a turbopump;

Connecting the second boiler body (for double-block turbines).

The number of experiments on each of the loads is: 2-3 at maximum, nominal and characteristic points and 1-2 at intermediate ones.

The duration of each of the experiments, excluding the adjustment of the mode, is at least 1 hour.

Before the main part of the test, it is planned to carry out so-called calibration experiments, the purpose of which is to compare the flow rates of live steam obtained by independent methods, which will make it possible to judge the "density" of the installation, i.e., the absence of noticeable unaccounted for steam and water supplies or their removal from the cycle. Based on the analysis of the convergence of the compared costs, in addition, a conclusion is made about the greater reliability of determining any of them; in this case, when processing the results, a correction factor is introduced to the flow rate obtained by another method. Carrying out these experiments may be especially necessary in the case when one of the narrowing measuring devices is installed or performed with a deviation from the rules.

It should also be taken into account that the results of calibration experiments can be used to more accurately determine by calculation the internal efficiency of the LPC, since in this case the number of quantities involved in the energy balance equation of the installation is reduced to a minimum.

To carry out calibration experiments, such a thermal scheme is assembled in which the flow rate of live steam can be almost entirely measured in the form of condensate (or exhaust steam for backpressure turbines), which is achieved by turning off the regenerative extractions at the HPH (or transferring their condensate to a cascade drain to the condenser ), a deaerator, if possible, on the LPH (if there is a device for measuring the condensate flow after the condensate pumps) and all withdrawals for general station needs. In this case, all steam and water inlets and their outlets from the turbine plant cycle must be reliably turned off and equal levels in the condenser at the beginning and end of each experiment must be ensured.

The number of calibration experiments in the range of changes in the flow rate of live steam from minimum to maximum is at least 7-8, and the duration of each is at least 30 minutes, provided that the pressure drops on the flow meters and the parameters of the environment in front of them are recorded every minute.

In the absence of a reliable dependence of the change in power on the pressure of the exhaust steam, it becomes necessary to conduct so-called vacuum experiments, during which the thermal scheme practically corresponds to that collected for calibration experiments. In total, two series of experiments are carried out with a change in the pressure of the exhaust steam from minimum to maximum: one - at a steam flow rate in the LPR close to the maximum, and the second - about 40% of the maximum. Each series consists of 10-12 experiments with an average duration of 15-20 minutes. When planning and conducting vacuum experiments, one should specifically mention the need to ensure the minimum possible fluctuations in the initial and final parameters of the steam in order to eliminate or minimize corrections to the turbine power in order to take them into account and, therefore, obtain the most representative and reliable dependence. The program should also stipulate a way to artificially change the pressure of the exhaust steam from experience to experience (for example, air inlet into the condenser, reduction of pressure of the working steam in front of the ejectors, change in the flow rate of cooling water, etc.).

Along with the above, some special experiments can be planned (for example, to determine the maximum power and throughput of the turbine, with a sliding pressure of live steam, to test the effectiveness of the implementation of various measures to determine the efficiency of the LPC, etc.).

B.3.2. Turbines with controlled steam extraction for heating

Turbines of this type (T) are made either with one stage of T-extraction taken from the chamber in front of the regulating body (these are, as a rule, turbines of old production and low power, for example, T-6-35, T-12-35, T- 25-99, etc., in which single-stage heating of network water is carried out), or with two stages of T-selection, one of which is fed from a chamber in front of the regulatory body (NTO), and the second - from a chamber located, as a rule, on two stages higher than the first (WTO) are, for example, turbines T-50-130, T, T-250/300-240 and others, currently produced and operating according to a more economical scheme with multi-stage heating of network water.

In turbines with multi-stage, and after a corresponding reconstruction and in turbines with single-stage heating of network water, in order to utilize the heat of the exhaust steam under the heat schedule mode, a built-in bundle (IP) is specially allocated in the condenser, in which the network water is preheated before it is supplied to the IWW. Thus, depending on the number of stages of heating of network water, there are modes with one-stage heating (LHTO is on), two-stage (HTO and WTO are on) and three-stage (HP, LHT and WTO are on).

The main dependence characteristic of turbines of this type is the mode diagram, which reflects the relationship between the flow rates of live steam and steam in the T-extraction and electric power. Being necessary for planning purposes, the regime diagram is at the same time the source material for calculating and standardizing the economic indicators of a turbine plant.

The regime diagrams for the operation of the turbine with one-, two- and three-stage schemes for heating network water are taken as two-field. Their upper field shows the dependences of the turbine power on the flow rate of live steam when operating according to the heat schedule, i.e. with a minimum steam flow in the LPR and various pressures in the RTO.

The lower field of the regime diagram contains the dependences of the maximum heating load on the turbine power, corresponding to the above-mentioned lines of the upper field. Additionally, lines are plotted on the lower field that characterize the dependence of the change in electric power on the heating load when the turbine is operating according to the electrical schedule, i.e., when steam passes in the low-pressure cylinder, greater than the minimum (only for one- and two-stage heating of network water).

Summer operation modes of turbines in the absence of heating load are characterized by dependences of the same type as for condensing turbines.

When testing turbines of this type, as well as for condensing turbines, it may also be necessary to experimentally determine some correction curves for turbine power for deviations of individual parameters from the nominal ones (for example, pressure of the exhaust steam or RTO steam).

Thus, the test program for turbines of this type consists of three sections:

Experiments on the condensation regime;

Experiments for constructing a regime diagram;

Experiments to obtain correction curves.

Each section is discussed separately below.

B.3.2.1. Condensation mode with off pressure regulator in RTO

This section consists of three parts, similar to those specified in the test program for the condensing turbine (calibration experiments, experiments with the design thermal scheme and experiments to determine the correction to the power for the change in exhaust steam pressure in the condenser) and does not require special explanations.

However, in view of the fact that, as a rule, the maximum flow rate of live steam in calibration experiments for turbines of this type is determined by the maximum pass in the LPP, the provision of a pressure drop in the narrowing devices on the live steam lines in the range above this flow rate to the maximum is carried out either by throttling the live steam, either by turning on the HPH with the direction of their heating steam condensate to the condenser, or by turning on the controlled selection and its gradual increase.

B.3.2.2. Experiments for constructing a regime diagram

From the structure of the diagram described above, it follows that in order to construct it, it is necessary to carry out the following series of experiments:

Thermal graph with different pressures in the RTO (to obtain the main dependencies of the upper and lower fields of the diagram. For each of the modes with one-, two- and three-stage heating of network water, 3-4 series are planned (6-7 experiments in each) with different constants pressures in the RHE equal to or close to the maximum, minimum and average, respectively.The range of change in the flow rate of live steam is determined mainly by the limitations of the boiler, the requirements of the instructions and the possibility of reliable measurement of costs;

Electric graph with constant pressure in the RTO (to obtain the dependence of power change on change in heating load). For each of the modes with one- and two-stage heating of network water at a constant flow rate of live steam, 3-4 series are planned (5-6 experiments in each) with a constant pressure in the RTO and a variable heating load from maximum to zero; It is recommended to turn off the HPT for the best accuracy.

B.3.2.3. Experiments for constructing correction curves for power for the deviation of individual parameters from their nominal values

It is necessary to carry out the following series of experiments:

Heat curve with constant live steam flow and variable pressure in the RHE (to determine the correction to the turbine power for a change in pressure in the RHE). For modes with one- and two-stage (or three-stage) heating of network water, two series of 7-8 experiments are carried out at a constant flow rate of fresh steam in each and a change in pressure in the RTO from minimum to maximum. The change in pressure in the RTO is achieved by changing the flow of network water through the PSV with the constant opening of the live steam valves and the minimum opening of the LPR rotary diaphragm.

The high pressure heaters are disabled to improve the accuracy of the results;

Experiments for calculating the correction to the power for the change in the pressure of the exhaust steam in the condenser. Two series of experiments are carried out at steam flow rates in the condenser of the order of 100 and 40% of the maximum. Each series consists of 9-11 experiments with a duration of about 15 minutes in the entire range of exhaust steam pressure change, carried out by air inlet into the condenser, change in cooling water flow rate, steam pressure by the main ejector nozzles, or flow rate of the steam-air mixture sucked from the condenser.

B.3.3. Turbines with controlled steam extraction for production

Turbines of this type have a very limited distribution and are produced either as condensing (P) or with backpressure (PR). In both cases, the diagram of their operation modes is single-field and contains the dependences of the electric power on the flow rates of live steam and P-extraction steam.

By analogy with sect. B.3.2 The test program also contains three sections.

B.3.3.1. Mode without P-selection

It is necessary to carry out the following experiments:

- "taring". Carried out under the conditions specified in sec. B.3.1 and B.3.2.1;

Under normal thermal conditions. They are carried out with the pressure regulator in the P-extraction turned off at a constant pressure of the exhaust steam (for turbines of the PR type).

B.3.3.2. Experiments for constructing a regime diagram

Due to the fact that the steam in the P-extraction chamber is always superheated, it is sufficient to conduct one series of experiments with controlled steam extraction, based on the results of which the characteristics of the HP and LPP are then calculated and plotted, and then the mode diagram.

B.3.3.3. Experiments for constructing correction curves for power

If necessary, experiments are carried out to determine the corrections to the power for changes in the pressure of the exhaust steam and steam in the P-extraction chamber.

B.3.4. Turbines with two adjustable steam extractions for production and heating (PT type)

The regime diagram for turbines of this type does not fundamentally differ from the traditional diagrams of double-selection turbines PT-25-90 and PT-60 with one heat extraction outlet and is also performed as a two-field one, while the upper field describes modes with production extraction, and the lower field describes modes with heat extraction at one - and two-stage heating of network water. Thus, to build a diagram, you need to have the following dependencies:

HPC and LPC capacities from the steam consumption at the inlet at the nominal pressures in the P-extraction and RTO and zero heating load (for the upper field) selected for the nominal pressures;

Changes in the total power of the switchable compartment (SW) and LPR for two-stage heating and LPR for one-stage heating from changes in the heating load.

In order to obtain the mentioned dependencies, it is necessary to carry out the following series of experiments.

B.3.4.1. Condensing mode

In this mode, experiments are carried out:

- "calibration" (PVD and pressure regulators in the selections are disabled). Such experiments are carried out with the thermal scheme of the installation assembled in such a way that the flow rate of live steam passing through the flow meter can be measured almost entirely in the form of condensate using a narrowing device installed on the main condensate line of the turbine. The number of experiments is 8-10 with the duration of each 30-40 minutes (see sections B.3.1 and B.3.2.1);

To calculate the power correction for the change in exhaust steam pressure in the condenser. The pressure regulators in the extractions are turned off, regeneration is turned off, except for LPH No. 1 and 2 (see Section B.3.1);

To determine the correction to power for a change in steam pressure in the RTO (HPH is off, the P-extraction pressure regulator is on). 4 series are carried out with a constant flow of fresh steam (4-5 experiments in each), in two of which the pressure in the WTO changes in steps from minimum to maximum, and in the other two - in the LTO;

With the design thermal scheme. Carried out under conditions similar to those specified in Sect. B.3.1.

B.3.4.2. Modes with production selection

A series of 4-5 experiments is carried out in the range of flow rates from the maximum in the condensing mode () to the maximum allowable when the HPC is fully loaded for steam ().

The value of P-selection is selected according to the conditions of the CHPP, based on the desirability of providing controlled pressure behind the HPC in the entire series of experiments.

B.3.4.3. Modes with heat extraction according to the electrical schedule (to obtain the dependence of power change on the change in heat load)

These modes are similar to those carried out during testing of turbines without P-bleed.

For modes with one- and two-stage heating of network water with the HPH turned off and the flow rate of live steam unchanged, 3-4 series of 5-6 experiments are carried out in each with a constant pressure in the RTO close to the minimum, intermediate and maximum, respectively.

The heating load varies from maximum to zero in each series of experiments by changing the flow of network water through the tube bundles of the IWW.

D. TEST PREPARATION

D.1. General provisions

Preparation for testing is usually carried out in two stages: the first covers work that can and should be carried out relatively long before testing; the second covers the work that is carried out immediately before the tests.

The first stage of preparation includes the following works:

Detailed familiarization with the turbine plant and instrumentation;

Drawing up a technical test program;

Drawing up an experimental control scheme (measurement scheme) and a list of preparatory work;

Drawing up a list (specification) of the necessary instrumentation, equipment and materials.

At the second stage of preparation, the following is performed:

Technical management and supervision of the implementation of preparatory work on the equipment;

Installation and adjustment of the measurement scheme;

Control of the technical condition of the equipment and the thermal circuit before testing;

Breakdown of measurement points by observation logs;

Drawing up work programs for individual series of experiments.

D.2. Familiarization with the turbine plant

When familiarizing yourself with the turbine installation, you must:

Examine the technical conditions for the supply and design data of the manufacturer, certificates of technical inspections, defect logs, operational data, standards and instructions;

To study the thermal scheme of the turbine plant from the point of view of identifying and, if necessary, eliminating or taking into account various intermediate inlets and outlets of steam and water for the duration of the test;

Determine what measurements need to be made to solve the problems posed before the test. Check in place the presence, condition and location of available measuring devices suitable for use during testing as main or backup;

By checking on site and interviewing the operating personnel, as well as studying the technical documentation, identify all noticed malfunctions in the operation of the equipment, relating, in particular, to the density of shut-off valves, heat exchangers (regenerative heaters, PSV, condenser, etc.), operation of the control system , the ability to maintain stable load conditions and steam parameters (fresh and controlled extractions) required during testing, the operation of level controllers in regenerative heaters, etc.

As a result of a preliminary acquaintance with the turbine plant, it is necessary to clearly understand all the differences in its thermal scheme from the design one and the parameters of steam and water from the nominal ones that may occur during testing, as well as ways to take these deviations into account when processing the results.

D.3. Measurement scheme and list of preparatory work

After a detailed acquaintance with the turbine plant and drawing up a technical test program, one should begin to develop a measurement scheme with a list of measured quantities, the main requirement for which is to provide the possibility of obtaining representative data characterizing the efficiency of the turbine plant as a whole and its individual elements in the entire range of modes outlined by the technical program. To this end, when developing a measurement scheme, it is recommended that the following principles be taken as a basis:

Use for measuring the main parameters of steam and water, generator power and flow rates of sensors and instruments of maximum accuracy;

Ensuring that the measurement limits of the selected instruments correspond to the expected range of changes in the fixed values;

Maximum duplication of measurements of the main quantities with the possibility of their comparison and mutual control. Connecting duplicate sensors to different secondary devices;

Use within reasonable limits of regular measuring instruments and sensors.

The measurement scheme for the turbine plant during the test, the lists of preparatory work (with sketches and drawings) and measurement points, as well as the list of necessary instrumentation (specification) are drawn up as an appendix to the technical program.

D.3.1. Drawing up a measurement scheme and a list of preparatory work for a turbine in operation

The thermal circuit of the turbine plant during the test must ensure a reliable separation of this installation from the general circuit of the power plant, and the measurement circuit must ensure the correct and, if possible, direct determination of all the quantities necessary to solve the problems posed before the test. These measurements should give a clear idea of ​​the flow balance, steam expansion process in the turbine, operation of the steam distribution system and auxiliary equipment. All critical measurements (for example, live steam flow rate, turbine power, parameters of live and exhaust steam, reheat steam, flow rate and temperature of feed water, main condensate, steam pressure and temperature in controlled extraction, and a number of others) must be duplicated, using the connection of independent primary converters to duplicating secondary devices.

A list of measurement points is attached to the thermal scheme, indicating their name and number according to the scheme.

Based on the developed measurement scheme and a detailed acquaintance with the installation, a list of preparatory work for testing is drawn up, which indicates where and what measures must be taken to organize a particular measurement and bring the circuit or equipment to a normal state (repair of fittings, installation of plugs, cleaning of surfaces heating heaters, condenser, elimination of hydraulic leaks in heat exchangers, etc.). In addition, the list of works provides, if necessary, for the organization of additional lighting at observation sites, the installation of signaling devices and the manufacture of various stands and fixtures for mounting primary converters, connecting (impulse) lines and secondary devices.

The list of preparatory work must be accompanied by sketches for the manufacture of the necessary primary measuring devices (bosses, fittings, thermometric sleeves, measuring narrowing devices, etc.), sketches of the tie-in locations of these parts, as well as various stands and fixtures for installing devices. It is also desirable to attach to the list a summary sheet for materials (pipes, fittings, cable, etc.).

The primary measuring devices listed above, as well as the necessary materials, are selected according to current standards in accordance with the parameters of the measured medium and technical requirements.

D.3.2. Drawing up a measurement scheme and a list of preparatory work for a newly installed turbine

For a newly mounted turbine, in particular the prototype, a slightly different approach is required to compiling a measurement scheme (or experimental control - EC) and issuing a task for preparatory work. In this case, the preparation of the turbine for testing should begin already during its design, which is caused by the need to provide in advance additional tie-ins in pipelines for the installation of measuring devices, since with modern thick-walled pipelines and a large amount of measurements caused by the complexity of the thermal circuit, all these works can be performed by power plants after putting the equipment into operation, it turns out to be practically impossible. In addition, the EC project includes a significant amount of instrumentation and necessary materials that the power plant is not able to purchase with their non-centralized supply.

Just as in preparation for testing turbines already in operation, it is necessary to first study the technical conditions for the supply and design data of the manufacturer, the thermal scheme of the turbine plant and its connection with the general scheme of the power plant, familiarize yourself with the standard measurements of steam and water parameters, decide , which can be used during the test as primary or backup measurements, etc.

After clarifying the above issues, it is possible to start drawing up the terms of reference for the design organization for inclusion in the working design of the station instrumentation of the EC project for thermal testing of the turbine plant.

- explanatory note, which sets out the basic requirements for the design and installation of the EC circuit, the selection and location of instrumentation; explanations are given for the equipment for recording information, the features of the use of types of wires and cables, the requirements for the room in which it is supposed to place the EC shield, etc.;

Scheme of the EC of the turbine plant with the name and numbers of measurement positions;

Specification for instrumentation;

Schemes and drawings for the manufacture of non-standard equipment (shield devices, segment diaphragms, intake devices for measuring vacuum in a condenser, etc.);

Schemes of pipe connections of pressure and differential pressure transducers, which provide various options for connecting them, indicating the numbers of measurement positions;

List of measured parameters with their breakdown by recording devices with indication of position numbers.

The places of insertion of measuring devices for EC on the working drawings of pipelines are usually indicated by the design organization and the manufacturer (each in its own design area) according to the terms of reference. If there are no tie-ins anywhere on the drawings, this is done by the enterprise that issued the terms of reference for the EC with a mandatory visa of the organization that issued this drawing.

It is desirable to install the EC circuit during the installation of the standard volume of instrumentation of the turbine plant, which makes it possible to start testing soon after the turbine plant is put into operation.

As an example, appendices 4-6 show the schemes of the main measurements during testing of turbines of various types.

D.4. Selection of instrumentation

The selection of instrumentation is carried out in accordance with the list compiled on the basis of the measurement scheme during testing.

For this purpose, only such instruments should be used, the readings of which can be verified by checking with exemplary ones. Devices with a unified output signal for automatic registration of parameters are selected according to the class of accuracy and reliability in operation (stability of readings).

The list of instrumentation required for testing should indicate the name of the measured quantity, its maximum value, type, accuracy class and instrument scale.

Due to the large volume of measurements during testing of modern high-power steam turbines, the registration of the measured parameters during the experiments is often carried out not by observers using direct-acting instruments, but by automatic recording devices with recording readings on a chart tape, multi-channel recording devices with recording on punched tape or magnetic tape, or operational information-computing complexes (IVC). In this case, measuring devices with a unified output current signal are used as primary measuring devices. However, in the conditions of power plants (vibration, dustiness, the influence of electromagnetic fields, etc.), many of these devices do not provide the necessary stability of readings and require constant adjustment. More preferable in this regard are the recently produced tensoresistor converters "Sapphire-22", which have a high accuracy class (up to 0.1-0.25) of sufficient stability. However, it should be borne in mind that when using the above transducers, it is desirable to duplicate the most critical measurements (for example, pressure in a controlled T-extraction, vacuum in a condenser, etc.) (at least during the period of accumulating experience in working with them), using mercury appliances.

To measure the pressure drop in the narrowing device, the following are used: up to a pressure of 5 MPa (50 kgf / cm2), two-pipe differential pressure gauges DT-50 with glass tubes, and at pressures above 5 MPa, single-tube differential pressure gauges DTE-400 with steel tubes, in which the mercury level is measured visually on a scale using an inductive pointer.

In an automated system for measuring the pressure drop, transducers with a unified output signal of the DME type of accuracy class 1.0 of the Kazan Instrument-Making Plant, DSE type of accuracy class 0.6 of the Ryazan plant "Teplopribor" and the above-mentioned tensoresistor transducers "Sapphire-22" ("Sapphire- 22DD") of the Moscow Instrument-Making Plant "Manometr" and the Kazan Instrument-Making Plant.

As direct-acting pressure measuring devices, for pressures above 0.2 MPa (2 kgf / cm2), spring pressure gauges of accuracy class 0.6 of the MTI type of the Moscow Instrument-Making Plant "Manometr" are used, and for pressures below 0.2 MPa (2 kgf /cm2) - mercury U-shaped pressure gauges, single-tube cup vacuum gauges, barovacuummetric tubes, as well as spring vacuum gauges and pressure vacuum gauges with an accuracy class of up to 0.6.

Thermal testing of steam turbines
and turbine equipment

In recent years, in the line of energy saving, attention has increased to fuel consumption standards for enterprises generating heat and electricity, therefore, for generating enterprises, the actual efficiency indicators of heat and power equipment are becoming important.

At the same time, it is known that the actual efficiency indicators under operating conditions differ from the calculated (factory), therefore, in order to objectively standardize fuel consumption for the generation of heat and electricity, it is advisable to test the equipment.

On the basis of equipment test materials, normative energy characteristics and a layout (order, algorithm) for calculating the norms of specific fuel consumption are developed in accordance with RD 34.09.155-93 "Guidelines for the compilation and maintenance of energy characteristics of thermal power plant equipment" and RD 153-34.0-09.154 -99 "Regulations on the regulation of fuel consumption at power plants."

Of particular importance is the testing of heat and power equipment for facilities operating equipment put into operation before the 70s and where modernization and reconstruction of boilers, turbines, auxiliary equipment was carried out. Without testing, normalization of fuel consumption according to the calculated data will lead to significant errors not in favor of generating enterprises. Therefore, the costs of thermal testing are negligible compared to the benefits.

The objectives of thermal testing of steam turbines and turbine equipment: determination of actual economy; obtaining thermal characteristics; comparison with manufacturer's warranties; obtaining data for standardization, control, analysis and optimization of turbine equipment operation; obtaining materials for the development of energy characteristics; development of measures to improve efficiency

The objectives of express testing of steam turbines: determination of the feasibility and scope of repairs; assessment of the quality and effectiveness of the repair or modernization; assessment of the current change in the efficiency of the turbine during operation.

Modern technologies and the level of engineering knowledge make it possible to economically upgrade units, improve their performance and increase their service life.

The main goals of modernization are:

• reduction of power consumption of the compressor unit;
• increase in compressor performance;
• increasing the power and efficiency of the process turbine;
• reduction of natural gas consumption;
• increasing the operational stability of equipment;
• reducing the number of parts by increasing the pressure of compressors and operating turbines at a smaller number of stages while maintaining and even increasing the efficiency of the power plant.

The improvement of the given energy and economic indicators of the turbine unit is carried out through the use of modernized design methods (solution of the direct and inverse problems). They are related:

• with the inclusion of more correct models of turbulent viscosity in the calculation scheme,
• taking into account the profile and end blockage by the boundary layer,
• elimination of separation phenomena with an increase in the diffuseness of the interblade channels and a change in the degree of reactivity (pronounced non-stationarity of the flow before the occurrence of surge),
• the possibility of identifying an object using mathematical models with genetic optimization of parameters.

The ultimate goal of modernization is always to increase the production of the final product and minimize costs.

An integrated approach to the modernization of turbine equipment

When carrying out modernization, Astronit usually uses an integrated approach, in which the following components of the technological turbine unit are reconstructed (modernized):

• compressor;
• turbine;
• supports;
• centrifugal compressor-supercharger;
• intercoolers;
• multiplier;
• Lubrication system;
• air cleaning system;
• automatic control and protection system.

Modernization of compressor equipment

The main areas of modernization practiced by Astronit specialists:

• replacement of flow parts with new ones (the so-called replaceable flow parts, including impellers and vaned diffusers), with improved characteristics, but in the dimensions of existing housings;
• reduction in the number of stages due to the improvement of the flow path based on three-dimensional analysis in modern software products;
• application of easy-to-work coatings and reduction of radial clearances;
• replacement of seals with more efficient ones;
• replacement of compressor oil bearings with "dry" bearings using magnetic suspension. This eliminates the use of oil and improves the operating conditions of the compressor.

Implementation of modern control and protection systems

To improve operational reliability and efficiency, modern instrumentation, digital automatic control and protection systems (both individual parts and the entire technological complex as a whole), diagnostic systems and communication systems are being introduced.

• STEAM TURBINES
• Nozzles and blades.
• Thermal cycles.
• Rankine cycle.
• Turbine structures.
• Application.
• OTHER TURBINES
• Hydraulic turbines.
• gas turbines.

Scroll upScroll down

Also on topic

• AIRCRAFT POWER PLANTS
• ELECTRIC ENERGY
• SHIP POWER PLANTS AND PROPULSIONS
• HYDROPOWER

TURBINE

TURBINE, prime mover with rotational movement of the working body for converting the kinetic energy of the flow of a liquid or gaseous working fluid into mechanical energy on the shaft. The turbine consists of a rotor with blades (bladed impeller) and a casing with nozzles. Branch pipes bring in and divert the flow of the working fluid. Turbines, depending on the working fluid used, are hydraulic, steam and gas. Depending on the average direction of flow through the turbine, they are divided into axial, in which the flow is parallel to the axis of the turbine, and radial, in which the flow is directed from the periphery to the center.

STEAM TURBINES

The main elements of a steam turbine are the casing, nozzles and rotor blades. Steam from an external source is supplied to the turbine through pipelines. In the nozzles, the potential energy of the steam is converted into the kinetic energy of the jet. The steam escaping from the nozzles is directed to curved (specially profiled) working blades located along the periphery of the rotor. Under the action of a jet of steam, a tangential (circumferential) force appears, causing the rotor to rotate.

Nozzles and blades.

Steam under pressure enters one or more fixed nozzles, in which it expands and from where it flows out at high speed. The flow exits the nozzles at an angle to the plane of rotation of the rotor blades. In some designs, the nozzles are formed by a series of fixed blades (nozzle apparatus). The vanes of the impeller are curved in the direction of flow and arranged radially. In an active turbine (Fig. 1, a) the flow channel of the impeller has a constant cross section, i.e. the speed in relative motion in the impeller does not change in absolute value. The steam pressure in front of the impeller and behind it is the same. In a jet turbine (Fig. 1, b) flow channels of the impeller have a variable cross section. The flow channels of a jet turbine are designed so that the flow rate in them increases, and the pressure decreases accordingly.

R1; c - blading the impeller. V1 is the steam velocity at the outlet of the nozzle; V2 is the speed of steam behind the impeller in a fixed coordinate system; U1 – peripheral speed of the blade; R1 is the speed of steam at the impeller inlet in relative motion; R2 is the speed of steam at the outlet of the impeller in relative motion. 1 - bandage; 2 - scapula; 3 – rotor." title="(!LANG:Fig. 1. TURBINE BLADES. a - active impeller, R1 = R2; b - jet impeller, R2 > R1; c - impeller blades. V1 - steam speed at the nozzle outlet; V2 is the steam velocity behind the impeller in a fixed coordinate system; U1 is the circumferential velocity of the blade; R1 is the steam velocity at the impeller inlet in relative motion; R2 is the steam velocity at the impeller outlet in relative motion. 1 - bandage; 2 - blade; 3 - rotor.">Рис. 1. РАБОЧИЕ ЛОПАТКИ ТУРБИНЫ. а – активное рабочее колесо, R1 = R2; б – реактивное рабочее колесо, R2 > R1; в – облопачивание рабочего колеса. V1 – скорость пара на выходе из сопла; V2 – скорость пара за рабочим колесом в неподвижной системе координат; U1 – окружная скорость лопатки; R1 – скорость пара на входе в рабочее колесо в относительном движении; R2 – скорость пара на выходе из рабочего колеса в относительном движении. 1 – бандаж; 2 – лопатка; 3 – ротор.!}

Turbines are usually designed to be on the same shaft as the device that consumes their energy. The speed of rotation of the impeller is limited by the tensile strength of the materials from which the disk and blades are made. For the most complete and efficient conversion of steam energy, turbines are made multi-stage.

Thermal cycles.

Rankine cycle.

In a turbine operating according to the Rankine cycle (Fig. 2, a), steam comes from an external steam source; there is no additional steam heating between the turbine stages, there are only natural heat losses.

Reheat cycle.

In this cycle (Fig. 2, b) steam after the first stages is sent to the heat exchanger for additional heating (overheating). Then it returns to the turbine again, where its final expansion takes place in subsequent stages. Increasing the temperature of the working fluid allows you to increase the efficiency of the turbine.

Rice. 2. TURBINES WITH DIFFERENT HEAT CYCLES. a – simple Rankine cycle; b – cycle with intermediate steam heating; c - cycle with intermediate steam extraction and heat recovery.

Cycle with intermediate extraction and utilization of exhaust steam heat.

The steam at the outlet of the turbine still has significant thermal energy, which is usually dissipated in the condenser. Part of the energy can be taken from the condensation of the exhaust steam. Some part of the steam can be taken from the intermediate stages of the turbine (Fig. 2, in) and is used for preheating, for example, feed water or for any technological processes.

Turbine structures.

The working medium expands in the turbine, so the last stages (low pressure) must have a larger diameter in order to pass the increased volume flow. The increase in diameter is limited by the allowable maximum stresses due to centrifugal loads at elevated temperatures. In split-flow turbines (Figure 3), the steam passes through different turbines or different turbine stages.

Rice. 3. TURBINES WITH FLOW BRANCHING. a - double parallel turbine; b – double turbine of parallel action with oppositely directed flows; c – turbine with flow branching after several stages of high pressure; d - compound turbine.

Application.

To ensure high efficiency, the turbine must rotate at high speed, but the number of revolutions is limited by the strength of the materials of the turbine and the equipment that is on the same shaft with it. Electric generators in thermal power plants are rated at 1800 or 3600 rpm and are usually installed on the same shaft as the turbine. Centrifugal superchargers and pumps, fans and centrifuges can be installed on the same shaft with the turbine.

The low speed equipment is coupled to the high speed turbine via a reduction gear, such as in marine engines where the propeller must rotate at 60 to 400 rpm.

OTHER TURBINES

Hydraulic turbines.

In modern hydraulic turbines, the impeller rotates in a special housing with a volute (radial turbine) or has a guide vane at the inlet to ensure the desired flow direction. The appropriate equipment is usually installed on the shaft of a hydroturbine (an electric generator at a hydroelectric power station).

gas turbines.

The gas turbine uses the energy of gaseous combustion products from an external source. Gas turbines are similar in design and principle of operation to steam turbines and are widely used in engineering. see also AVIATION POWER PLANT; ELECTRIC ENERGY; SHIP POWER INSTALLATIONS AND ENGINES; HYDROPOWER.

Literature

Uvarov V.V. Gas turbines and gas turbine plants. M., 1970
Verete A.G., Delving A.K. Marine steam power plants and gas turbines. M., 1982
Trubilov M.A. and etc. Steam and gas turbines. M., 1985
Sarantsev K.B. and etc. Atlas of turbine stages. L., 1986
Gostelow J. Aerodynamics of turbomachinery gratings. M., 1987