RU2472974C2 - Method of gas turbine engine protection - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: air pressure downstream of compressor is measured at all operating conditions to calculate relative variation and relative air pressure variation rate behind the compressor. Relative pressure variation is compared with first preset magnitude defined for every gas turbine engine experimentally. Relative pressure variation rate is compared with second preset magnitude defined for every gas turbine engine experimentally. In case relative pressure variation exceeds said first preset magnitude and relative variation rate exceeds second preset magnitude, signal "SURGE" is generated to stop fuel feed in combustion chamber for preset time defined for every engine in acceptance tests. Valve to bypass air from intermediate sections of engine compressor and from behind the compressor is opened to cut on ignition switch for preset time. In case relative pressure rate falls below first preset magnitude and relative pressure variation is lower than second preset magnitude, signal "SURGE" is removed to control gas turbine engine in compliance with standard control programs.

EFFECT: higher quality of automatic control system, reliability of engine and aircraft safety.

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Description

The invention relates to the field of aircraft engine manufacturing and can be used in electronic hydromechanical systems (ACS) for automatic control of gas turbine engines (GTE).

A known method of protecting a gas turbine engine against overheating of a gas generator is implemented in a hydromechanical self-propelled guns with an electronic gas temperature limiter behind the turbine, which measures the temperature of the gases behind the turbine, compares its value with the maximum permissible value if the measured gas temperature exceeds the limit value by a predetermined value, turn off the engine. Keba I.V. “Flight operation of helicopter GTE”, Moscow, “Transport”, 1976, p.180-182.

The disadvantage of this method is its low efficiency and the inability to use on single-engine aircraft (LA).

Closest to this invention by technical essence is a method of protecting a gas turbine engine, which consists in measuring the temperature of the gases behind the turbine, comparing its value with the set value, if the measured gas temperature has exceeded the set value, and reducing the fuel consumption in the gas turbine combustion chamber (КС) to those while the measured gas temperature does not become less than the set value, in the start-up mode of the gas turbine engine at equal intervals of time, set in advance, the magnitude of the change in gas temperature and rotor speed of the rotor is calculated For a given period of time, the magnitude of the change is filtered using a first-order aperiodic link with a time constant twenty-five times greater than the specified period of time, the ratio of the filtered magnitude of the change in gas temperature to the filtered magnitude of the change in the frequency of rotation of the engine rotor is calculated if the ratio exceeds the predetermined value for a predetermined time, generate a signal "Dangerous engine operation" and stop the flow of fuel to the gas turbine engine for a time of 0.3 ... 0.5 seconds, atent RF №2329388 from July 20, 2008

The disadvantage of this method is that it does not protect the engine from a deep loss of gas-dynamic stability - surge, allowing you to eliminate only stall phenomena in the compressor. This reduces engine reliability and aircraft safety.

The aim of the invention is to improve the quality of ACS and, as a result, increase the reliability of the engine and the safety of the aircraft.

This goal is achieved by the fact that in the method of protecting a gas turbine engine consisting in measuring the temperature of the gases behind the turbine, comparing its value with the set value, if the measured gas temperature has exceeded the set value, reducing fuel consumption in the gas turbine engine until the measured gas temperature will become less than the set value, in the start-up mode of the gas turbine engine at equal intervals of time specified in advance, the magnitude of the change in gas temperature and the rotational speed of the engine rotor for a given period of time is calculated, The filters are filtered using a first-order aperiodic link with a time constant twenty-five times greater than a predetermined period of time, the ratio of the filtered value of the change in gas temperature to the filtered value of the change in the frequency of rotation of the engine rotor is calculated if the ratio exceeds a predetermined value for a predetermined time, generate a signal "Dangerous engine operation" and stop the flow of fuel to the engine of the gas turbine engine for a time of 0.3 ... 0.5 seconds, in addition to all modes of operation of the gas turbine engine from a minimum To the maximum, measure the air pressure behind the compressor, calculate the relative change and the relative rate of change of air pressure behind the compressor, compare the relative pressure change with the first predetermined value determined experimentally for each type of gas turbine engine, and the relative speed with the second predetermined value determined for of each type of gas turbine engine experimentally, if the relative change in pressure is greater than the first predetermined value, and the relative speed is more than watts swarm in advance of a predetermined value, generate the “Pompage” signal, cut off the fuel supply to the gas turbine engine for a predetermined time, determined experimentally for each gas turbine engine during acceptance tests, open the air bypass valves due to the intermediate stages of the gas turbine compressor and because of the compressor GTE and turn on the ignition unit for a predetermined time, if after that the relative pressure change is less than the first ahead of the set value, and the relative speed is less than the second ahead of the set value, take off Igna "surging" and is carried CCD control according to the regular control programs.

The figure shows a diagram of a device that implements the inventive method.

The device contains a series-connected sensor block 1 (DB 1), an electronic regulator 2 (RED 2), a fuel metering unit 3 (DT 3), a fuel shut-off valve 4 (KO 4), and DT 3 is connected to BD 1 and KO 4 - to the ER 2, the signal board 5 of the crew of the aircraft connected to the ER 2.

RED 2 is an on-board digital computer (BCM), which contains read-only memory (ROM), which contains software (software) that implements engine control algorithms. Additionally, the digital computer is equipped with input / output devices (I / O) of physical signals (from DB 1 and DT 3), random access memory (RAM), which is necessary for the processor to process information coming from the air-blast computer, a programmable memory device (RPZU), which is required to store information, related to the individual characteristics of the engine (operational adjustments, operating hours, remaining life). A computer, ROM, software, air-blast, RAM, processor, RPG are not shown in the figure.

The device operates as follows.

In RED 2, using DB 1, the temperature of the gases behind the turbine is measured and its value is compared with the set value stored in the ROM (for the PS-90A2 engine manufactured by Aviadvigatel OJSC, Perm, the set temperature of the gases behind the low-pressure turbine is 855 K). If the measured gas temperature has exceeded the set value, by the command of the RED 2 using DT 3 reduce the fuel consumption in the compressor until the measured temperature of the gases becomes less than the set value.

Additionally, at engine start mode in RED 2:

- at regular intervals specified in advance (for example, for electronic regulators RED-90 developed and manufactured by STAR OJSC, Perm, included in the ACS of PS-90A engines developed by OJSC Aviadvigatel, Perm, this interval is 0 , 02 seconds) calculates the magnitude of the change in gas temperature and engine rotor speed for a given period of time;

- the magnitude of the change is filtered using a first-order aperiodic link with a time constant ten times larger than a given period of time (for PS-90A engines this constant is 0.5 seconds);

- calculates the ratio of the filtered magnitude of the change in gas temperature to the filtered magnitude of the change in rotational speed of the engine rotor;

- compares the ratio with a predetermined value (for PS-90A engines this value is 0.48 K x second);

- if the ratio exceeds the predetermined value in advance for the predetermined time (for PS-90A engines this time is 0.5 seconds), it generates a signal on the display 5 “Dangerous engine operation” and stops for 0.3 ... 0.5 seconds supplying fuel to the engine's compressor station, turning on KO 4. Usually this is enough to stop the increase in gas temperature, dangerous for the gas generator, caused by stalling phenomena in the compressor, and stop the engine working normally.

Additionally, at all modes of operation of the gas turbine engine from minimum to maximum, air pressure behind the compressor is measured with the help of OBD 1 in RED 2, the relative change and relative rate of change of air pressure behind the compressor are calculated, the relative pressure change is compared with the first predetermined value determined for each type of gas turbine engine experimentally, and the relative speed with a second predetermined value determined for each type of gas turbine engine experimentally, if the relative change in pressure is greater ervoy preassigned value, and the relative rate - more than the second prescribed value, forming the signal "Surging" outputted on the display 5.

For example, for the PS-90A2 engine developed by Aviadvigatel OJSC, the electronic regulator SAU RED-90A2M at engine operating modes above 5000 rpm should generate a "surge" signal with the following conditions:

,1) the relative pressure drop behind the compressor by an amount greater

,

- размах пульсационной составляющей давления воздуха (кгс/см²);Where

- the range of the pulsation component of the air pressure (kgf / cm ² );

- максимальное давление за каждый цикл колебания (кгс/см²).

- maximum pressure for each oscillation cycle (kgf / cm ² ).

2) the relative rate of change of pressure

where Δτ is the RED-90A2M calculation cycle, equal to 0.05 s.

At the same time, by the command of RED 2, using KO 4, the fuel supply to the gas turbine engine is stopped for a predetermined time, determined experimentally for each gas turbine engine during acceptance tests (for the PS-90A2 engine this time is 0.3 s), open the air bypass valves because of the intermediate stages of the gas turbine compressor (PS-90A2 engine has air bypass flaps due to the retaining stages of the compressor ZPV PS) and because of the gas turbine compressor (PS-90A2 has the KPV KVD) and they turn on the ignition unit for a predetermined time ( for PS-90A2 this time is 30 s).

Usually this is enough to take the engine out of surge.

If after that the relative pressure change is less than the first forward set value (for PS-90A2 the value is 0.4), and the relative speed is less than the second ahead set value (for PS-90A2 the value is 7), the “Surge” signal issued RED 2 on the scoreboard 5, remove the signal RED 2 on KO 4 and by the commands RED 2 using DT 3 control GTE in accordance with regular control programs stored in ROM RED 2.

T.O. By improving the quality of the ACS, the engine is protected from surging, which increases the reliability of the engine and the safety of the aircraft.

Claims (1)

A method of protecting a gas turbine engine (GTE), which consists in measuring the temperature of the gases behind the turbine, comparing its value with the set value, if the measured gas temperature has exceeded the set value, reducing fuel consumption in the gas turbine engine until the measured gas temperature becomes lower the set value, in the start-up mode of the gas turbine engine at equal intervals of time specified in advance, the magnitude of the change in the temperature of the gases and the rotational speed of the engine rotor for a given period of time is calculated, the magnitude of the change is filtered t using a first-order aperiodic link with a time constant twenty-five times greater than a predetermined period of time, calculate the ratio of the filtered value of the change in gas temperature to the filtered value of the change in the frequency of rotation of the engine rotor, if the ratio exceeds the predetermined value during the predetermined time, form signal "Dangerous engine operation" and stop the flow of fuel to the engine of the gas turbine engine for a time of 0.3 ... 0.5 s, characterized in that in addition to all modes of operation of the gas turbine engine from min to maximum, measure the air pressure behind the compressor, calculate the relative change and the relative rate of change of air pressure behind the compressor, compare the relative pressure change with the first predetermined value determined experimentally for each type of gas turbine engine, and the relative speed with the second predetermined value determined for of each type of gas turbine engine experimentally, if the relative change in pressure is greater than the first predetermined value, and the relative speed is greater In advance, of a predetermined value, the signal "Pompage" is generated, the fuel supply to the gas turbine engine is stopped for the predetermined time determined for each gas turbine engine experimentally during acceptance tests, the air bypass valves are opened due to the intermediate stages of the gas turbine compressor and because of the gas turbine compressor and turn on the ignition unit for a predetermined time, if after this the relative pressure change is less than the first predetermined value, and the relative speed is less than the second predetermined value, signal "surging" and is carried CCD control according to the regular control programs.

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