RU2389891C1 - Control method of air leakages and flow for turbine cooling in double-flow gas turbine engine - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: control method of air leakages and flow for turbine cooling in double-flow gas turbine engine involves determination of air flow Gac at compressor inlet, air flow Gat through nozzle device of turbine and air flow Gal for leakages and for cooling of turbine; at that, air flow Gal through nozzle device of turbine is determined by mathematical processing of flow values of fuel, air temperature and pressure before and after compressor, rotor rpm of compressor, which are measured during engine test; air flow Gac at compressor inlet is determined as per compressor characteristic connecting air flow, rotation speed and pressure increasing degree, taking into account pressure increasing degree of compressor and reduced compressor rpm calculated as per parametres measured during engine test, and air flow Gac for leakages and cooling of turbine is determined by difference between air flow Gac at compressor inlet and air flow Gat through nozzle device of turbine.

EFFECT: invention allows improving accurate control of leakages and flow of air taken for cooling of turbine in double-flow gas turbine engine.

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Description

The invention relates to tests of gas turbine engines, in particular to the determination in tests of air flow for leaks in the compressor air path and combustion chamber and air flow for cooling a turbine and can be used in aircraft engine manufacturing.

It is known that when designing an engine, mathematical formulas are used to determine the amount of leakage and air flow for cooling a turbine in a double-circuit gas turbine engine, which include the calculated gas-dynamic parameters and geometric dimensions of this type of engine (see G.S.Zhiritsky, V.I. Lokay “Gas turbines of aircraft engines, M. Mechanical Engineering, 1971, pp. 178-182,336-342).

However, when determining leaks and air flow for cooling a turbine in a double-circuit gas turbine engine by calculation, it is impossible to take into account all technological deviations inevitable in engine production, leading to a deviation from a given geometry and a change in gas-dynamic parameters. In this regard, for a reliable assessment of the quality of manufacture and assembly of the engine, it is necessary to determine the actual leakage and air flow for cooling the turbine of each engine instance.

EFFECT: increased reliability of control of leaks and air consumption taken for cooling a turbine in a double-circuit gas turbine engine.

This result is achieved in that a method for monitoring leaks and air flow for cooling a turbine in a double-circuit gas turbine engine includes determining air flow rate Gvk at the compressor inlet, air flow rate Gvt through the turbine nozzle and air flow rate Gvu for leakage and cooling of the turbine, while of air GW through a nozzle apparatus of a turbine is determined by mathematical processing of the values of fuel consumption measured during the engine test, temperature and air pressure in front of and behind the compressor, numbers compressor rotor revolutions, air flow rate Gвк at the compressor inlet is determined by the compressor characteristic that relates the air flow rate, the number of revolutions and the degree of pressure increase, taking into account the degree of compressor pressure increase and reduced compressor revolutions calculated according to the parameters measured as a result of engine tests, and the flow rate Gvu air leakage and cooling of the turbine is determined by the difference between the air flow rate Gvk at the inlet to the compressor and the air flow rate Gwt through the nozzle apparatus of the turbine.

Compressor characteristics are understood as graphic or analytical dependencies that relate gas flow rate, speed, degree of increase in pressure and efficiency for various operating modes.

The drawing shows a graph of the degree of increase in pressure π _to the air flow Gв.

The method is implemented as follows.

A double-circuit gas turbine aircraft engine is tested. When testing using well-known test facilities, see, for example, G.M. Gorbunov, E.L. Solokhin, “Testing of aircraft-jet engines,” M, Mechanical Engineering, 1967, pp. 25-28. During the engine test, the temperature and air pressure are measured in front of and behind the compressor, the rotational speed of the high pressure rotor and fuel consumption using known measuring devices (for example, pressure gauges, thermometers, etc.). Then, using mathematical formulas, the air flow rate Gv.typ is determined through the nozzle apparatus of a high-pressure turbine. To do this, substituting the measured parameters during the engine test in the formula 1 and 2 and solving them as a system, determine the gas flow rate G _g through the nozzle apparatus of the turbine:

Where

C _p is the specific heat;

T * _g - gas temperature in front of the turbine;

T * _k - air temperature behind the compressor;

H _u - calorific value of the fuel;

i is the enthalpy;

Where

And _g is the gas flow rate;

G _g - gas consumption;

T * _g - gas temperature;

P * _g - gas pressure

(see L. S. Skubachevsky "Testing of jet engines", M., Mechanical Engineering. 1972, p. 63).

The flow rate of air entering the nozzle apparatus from the combustion chamber is determined by the formula 3:

Where

G _g - gas consumption;

G _t - fuel consumption.

To determine the air flow rate Gвк at the compressor inlet, the reduced compressor revolutions (according to formula 4) and the degree of pressure increase in the compressor π _к1 (according to formula 5) are calculated in values 4 and 5 are substituted with the values obtained during the engine test.

The given compressor speed is calculated by the formula 4:

Where

T * _n - temperature at the inlet to the compressor;

n _deputy - the number of revolutions measured;

The degree of pressure increase in the compressor according to the formula 5:

Where

R * k - air pressure at the outlet of the compressor;

P * a - air pressure at the inlet to the compressor;

Further, using the compressor characteristic (see Fig. 1), we determine from this graph the air flow rate Gвк at the compressor inlet.

A compressor characteristic relating air flow, speed and pressure increase is a known characteristic for each particular type of compressor.

The magnitude of the leakage and air flow rate for cooling the air turbine Gvu in the compressor air path and the combustion chamber of the dual-circuit gas turbine engine is determined as the difference between the air flow through the compressor Gvk and the air flow Gv.typ through the nozzle of the turbine: Gvu = Gvk-Gv.typ. The data obtained make it possible to determine the actual level of air leaks and the amount of air for cooling the turbine, which allows you to control the quality of each engine and the stability of mass production.

Claims (1)

A method for monitoring leaks and air flow for cooling a turbine in a double-circuit gas turbine engine, including determining air flow rate Gvk at the compressor inlet, air flow rate Gw through a turbine nozzle and air flow rate Gvu for leakage and cooling a turbine, while air flow rate Gw through a nozzle apparatus turbines are determined by mathematical processing of the values of fuel consumption measured during the engine test, temperature and air pressure in front of and behind the compressor, compressor rotor speed, flow rate air Gvk at the inlet to the compressor is determined by the characteristics of the compressor, connecting the air flow rate, the number of revolutions and the degree of increase in pressure, taking into account the degree of increase in compressor pressure and reduced compressor revolutions calculated from the parameters measured as a result of engine tests, and the air flow rate Gvu for leakage and turbine cooling is determined by the difference between the air flow rate Gвк at the compressor inlet and the air flow rate Гвт through the nozzle apparatus of the turbine.

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