RU2739168C1 - Test bench for gas generator of turbojet by-pass engine - Google Patents

Abstract

FIELD: aviation.SUBSTANCE: invention relates to tests of aircraft air-jet engines and can be used in aircraft engineering. Test bench comprises air supply system, gas discharge system, inlet device, exhaust device, supply, exhaust and bypass air pipelines, engine outer circuit process channel, receiver, air flow equalizing device, an air discharge system, two exhaust shafts and a thermo-pressure chamber with a dynamometric platform placed therein for mounting the test gas generator. Exhaust device includes series-connected ejector-gas duct, exhaust diffuser and gas-water cooler. Inlet device comprises stationary part and movable part intended for connection with gas generator inlet. Exhaust, supply and bypass pipelines are equipped with shutoff-control devices.EFFECT: invention allows providing complex check of strength characteristics and gas-dynamic compliance of gas turbine engine components, including transient modes of operation in extended range of gas generator operating conditions as per the turbojet engine by height and flight Mach number.1 cl, 5 dwg

Description

The invention relates to testing aircraft jet engines, in particular to stands for testing gas generators of turbojet bypass engines (TRDD), and can find application in the aviation industry.

A known stand for testing a turbojet bypass engine (RU 2467302, 2012), containing an air supply system, a gas exhaust system, an inlet device, an exhaust device, an inlet and outlet air pipelines, a receiver and a thermal pressure chamber with a dynamometric platform placed inside it, designed to install the tested turbojet engine , moreover, the supply pipeline is equipped with shut-off and control devices, the outlet of the air supply system is in communication with the supply pipeline, and the inlet of the gas removal system is connected to the exhaust pipeline, the exhaust device is installed at the outlet of the thermal vacuum chamber and communicated with the inlet of the gas removal system through the exhaust pipeline, the supply pipeline is connected to receiver input, the receiver output is communicated with the input device through the attachment.

The disadvantage of the known technical solution is that it is not intended for testing gas generators and does not contain means that allow testing in accordance with the requirements provided for in clause 5.1 "Testing methods of a gas turbine engine to check its performance and efficiency" in the "Manual for testing aviation engines at high-altitude and climatic stands ", TsIAM, 2012, p. 65 (hereinafter - Test Method).

The closest analogue of the claimed invention is a stand for testing a gas generator of a turbojet bypass engine (RU 2622588, 2017), containing an air supply system, a gas exhaust system, an inlet device, an exhaust device, an inlet, exhaust and bypass air pipelines, and the exhaust and bypass pipelines are equipped with a shut-off - regulating devices, the outlet of the air supply system is in communication with the supply pipeline, and the inlet of the gas removal system is in communication with the exhaust pipeline.

The disadvantage of the known stand for testing the gas generator TRDD is that it allows testing under limited conditions for the total pressure P * _BX and the inhibited temperature T * _BX at the inlet to the gas generator under conditions of excess air pressure at the inlet to the gas generator above atmospheric, which mainly corresponds to the modes carrying out strain gauging of the gas generator.

To supply air to the inlet to the gas generator in the known stand, air is taken from the external circuit of the D-30T technological turbojet engine, the minimum total pressure of which cannot be less than 125 kPa. At lower values of pressure in the channel of the outer loop of the technological turbofan engine, due to a decrease in the ratio of the rotational speeds of the high-pressure compressor and the low-pressure compressor (LPC) in accordance with the characteristics of the operating modes of the LPC of the technological turbofan engine, the LPC may surge.

In this case, the retarded temperature Т * _ВХ of the air flow supplied at the inlet to the gas generator depends significantly on the ambient temperature in the atmosphere, which may not allow conducting climatic tests of the gas generator at low temperatures of the air flow at the inlet, for example, when testing the start of the gas generator in high-altitude conditions and when checking the absence of vibration combustion in the combustion chamber of the gas generator.

The known stand also lacks technical means that allow setting the value of the static pressure _RB on the stand outside the working stream of gases from the jet nozzle of the gas generator below atmospheric. This drawback, in particular, does not allow simulating cruising flight conditions at the stand.

Η = 11 km (R _B = 22.61 kPa),

and Mach number

M _P = 0.8,

as a result, the line of operating modes on the characteristic of the gas generator compressor will shift towards the border of unstable modes, which will lead to a decrease in the reserves of its gas-dynamic stability and to overheating of the material of the high-pressure turbine of the gas generator. In this case, the value of the resultant axial force acting on the angular contact bearing of the gas generator can also change.

There are also significant restrictions in the implementation of changes in the air supply in the known stand at different operating modes of the gas generator, since shut-off and control devices used for this purpose are intended only for an emergency change in the flow rate of air bypassed into the atmosphere from an air duct pressurized in an emergency, for example, during pumping of a gas generator or a technological turbojet engine, or can be used only when the total pressure before entering the gas generator exceeds the value of atmospheric pressure.

Another disadvantage of the known stand is the lack of means for reducing the level of unevenness of the flow rate and the intensity of the flow pressure pulsations at the gas generator inlet.

The well-known stand also lacks means that allow testing a gas generator with a process channel of the outer circuit of a turbojet engine, for example, a turbojet engine with LPC with retaining stages of the PD-14 type, into which it is necessary to supply a flow with parameters in terms of total pressure and decelerated temperature corresponding to the parameters behind the turbojet fan, and at the entrance to the gas generator - with the parameters corresponding to the parameters behind the LPC retaining stages, which does not meet the requirements of paragraph 5.1 of the above Test Methodology.

The technical problem to be solved by the claimed invention is the lack of means that allow testing the gas generator in an extended range of operating conditions as part of a turbojet engine, including the total pressure Р * _ВХ , decelerated temperature Т * _ВХ , static pressure Р _B at the stand , as well as in transient modes of operation.

The technical result achieved in the implementation of the claimed invention is to provide a comprehensive check of the strength characteristics and gas-dynamic compliance of the gas generator units of the turbojet engine, including the transient modes of operation in an extended range of operating conditions of the gas generator as part of the turbojet engine in terms of height and flight Mach number.

The claimed technical result is achieved due to the fact that the stand for testing the gas generator of a turbojet bypass engine contains an air supply system, a gas exhaust system, an inlet device, an exhaust device, supply, exhaust and bypass air pipelines, and the exhaust and bypass pipelines are equipped with locking and regulating devices, the first outlet of the air supply system is in communication with the supply pipeline, and the inlet of the gas removal system is in communication with the exhaust pipeline, while the stand is additionally equipped with a technological channel of the external engine circuit, a receiver, a device for equalizing the air flow, an air exhaust system, two exhaust shafts and a thermal pressure chamber with inside it by a dynamometric platform designed to install the tested gas generator, while the exhaust device includes a series-connected ejector-gas conduit, an exhaust diffuser and a gas-water cooler supplying air pipes The conduit is equipped with a shut-off and regulating device, the inlet device contains a fixed part and a movable part intended for connection with the gas generator inlet, a device for leveling the air flow is installed in front of the first outlet of the receiver, the exhaust device is installed at the outlet of the thermal vacuum chamber and communicated with the inlet of the gas removal system by means of an exhaust pipeline , the supply pipeline is in communication with the inlet of the receiver, the first outlet of the receiver is in communication with the inlet through the nozzle, the second outlet of the receiver is in communication with the inlet of the air exhaust system by means of a bypass pipeline, and the exhaust shafts are connected, respectively, with the exhaust and bypass pipelines and are equipped with shut-off and control devices.

Essential signs can be developed and continued. At the second outlet of the air supply system, an additional pipeline with a shut-off and control device can be installed, and the outlet of the additional pipeline is equipped with a flow manifold and a flexible bellows, the outlet of which is connected to the process channel of the external engine circuit.

These essential features provide a solution to the technical problem posed with the achievement of the claimed technical result, since only the combination of features that make up the invention allows for a comprehensive check of the strength characteristics and gas-dynamic compliance of the gas generator units of the turbofan engine, including in transient operating modes in an extended range of operating conditions of the gas generator in the composition of the turbojet engine in altitude and flight Mach number.

The technical solution makes it possible to test the gas generator under conditions that maximally simulate the operating conditions of the gas generator as part of the turbofan engine, in accordance with the requirements provided for in paragraph 5.1 of the Test Procedure.

The present invention is illustrated by the illustrations presented in Figures 1-5, where:

in fig. 1 shows the general layout of the stand for testing the turbojet engine;

in fig. 2 shows a diagram of a gas removal system;

in fig. 3 shows the design of the inlet of the stand;

in fig. 4 shows a diagram of a fragment of a test bench for testing a turbojet engine with an additional pipeline;

in fig. 5 shows the area of testing the gas generator in the coordinates of the operation of the turbojet engine in height (H) and the number (M _P ) of the flight Mach in the subsonic aircraft at the declared stand.

The test bench for the gas generator of a turbojet bypass engine includes an air supply system 1, a gas outlet system 2, an inlet device 3, an exhaust device 4, an air supply line 5, an exhaust air line 6, a bypass air line 7, a process channel 8 of the external engine circuit, a receiver 9 , a device 10 for equalizing the air flow, an air exhaust system 11, a first exhaust duct 12, a second exhaust duct 13 and a thermal pressure chamber 14 with a dynamometric platform 15 located inside it, designed to install the tested gas generator 16 (Fig. 1).

The first outlet of the air supply system 1 is in communication with the supply pipeline 5, and the inlet of the gas outlet system 2 is in communication with the exhaust pipeline 6. A device 10 for equalizing the air flow is installed in front of the first outlet of the receiver 9, the exhaust device 4 is installed at the outlet of the thermal pressure chamber 14 and communicated with the inlet of the system 2 gas removal through the exhaust pipe 6, the supply pipe 5 is in communication with the inlet of the receiver 9, the first outlet of the receiver 9 is in communication with the inlet 3 through the nozzle 17, the second outlet of the receiver 9 is in communication with the inlet of the air removal system 11 through the bypass pipeline 7, and the exhaust shafts 12 , 13 are connected, respectively, with the exhaust and bypass pipelines 6, 7 and are equipped with shut-off and control devices 18, 19.

The air supply system 1 is designed to provide the required values of the total pressure, the decelerated temperature of the air flow in front of the test gas generator and the mass air flow rate. Air supply system 1 in a particular case (Skibin V.A., "Modern methods and equipment for testing air-jet engines", Moscow, MATI, 2000, p. 21, 283-289) includes suction shafts, shut-off control devices, air filters, compressors, air-to-air and high-temperature refrigerators, a refrigeration turbine and an air mixer (not shown in the drawings).

The supply, exhaust and bypass pipelines 5, 6, 7 are equipped with locking and regulating devices 20, 21, 22, 23.

The exhaust device 4 includes a series-connected ejector-gas conduit 24, an exhaust diffuser 25 and a gas-water cooler 26.

In a particular case, each of systems 2 and 11 includes two parallel-connected exhaust stations 27 and 28, respectively, each of which includes a series-connected shut-off and control devices 29, a gas-water cooler 30 and an exhauster 31 (Fig. 2). The outlet of each exhaust station 27, 28 is connected to an exhaust shaft 32.

The input device 3 can be used as an input device, the design of which is described in the patent (RU 2439526, 2012). The inlet device 3 comprises a stationary part 33 and a movable part 34 intended for connection to the inlet of the gas generator 16 (see Fig.). The stationary and movable parts 33, 34 are connected by means of a labyrinth seal 35. The movable part 34 is fixed on the dynamometer platform 15 by means of support and support-and-stop posts 36 and 37, respectively.

The dynamometric platform 15 can be fixed on an elastic suspension (not shown in the drawing) such as compression bands or tension bands (Pavlov Yu.I. et al. "Design of test stands for aircraft engines", Moscow, "Mashinostroenie", 1979, p. 89 -105) to the thermal pressure chamber 14 and allows you to measure the force from the thrust of the gas generator 16, which in a particular case can be installed on the sub-engine frame 38, fixed on the dynamometer platform 15.

The device 10 for leveling the air flow in a particular case includes a protective grid 39, leveling grids 40 to ensure the required uneven flow rate and intensity of pressure pulsations and a honeycomb device 41 placed between them to eliminate large-scale vortices, straighten the flow in the axial direction and eliminate swirl flow before entering the gas generator 16 after turns of the flow in the pipeline by 180 ° (R. Pankhurst and D. Holder. "Experimental technique in wind tunnels". Publishing house "Foreign literature", M., 1955, pp. 86-90).

The nozzle 17 can be made along the profile of the Vitoshinsky nozzle or along the profile of the lemniscate.

In a particular case, at the second outlet of the air supply system 1, an additional pipeline 42 with a shut-off and control device 43 is installed, and the outlet of the additional pipeline 42 is equipped with a flow manifold 44 and a flexible bellows 45, the outlet of which is connected to the process channel 8 of the external engine circuit (see Fig. 4).

Locking and regulating devices (ZRU) 18, 19, 20, 21, 22, 23, 29, 43 can be made in the form of throttles of various designs (Nasonov V.N., Pavlov Yu.I. et al., "Design of technological equipment high-rise stands for testing aircraft engines ". Moscow, MATI, 2005, pp. 104-123). The throttle drive can be mechanical (using hydraulic drives) and electromechanical (using stepper motors). Locking and regulating devices regulate the air flow by changing the parameters of the flow of the air flowing through it, until it stops completely (closed position of the throttle).

The stand for testing the gas generator of a turbojet bypass engine operates as follows.

The air flow from the air supply system 1 with the required parameters corresponding to the total pressure P * _LPC and temperature T * _LPC braking behind the low-pressure compressor (LPC) of the turbojet engine with or without back-up stages enters the receiver 9 through the supply pipeline 5, passes through the device 10 to equalize the air flow and along the movable (outlet) part 34 of the inlet device 3 is fed to the inlet of the tested gas generator 16.

The gas flow from the jet nozzle of the tested gas generator 16 when tested in conditions close to ground

(Н ≈ 0 km, М _П ≥ 0),

goes to the exhaust device 4, in which it is pre-cooled, and then through the exhaust pipe 6 into the atmosphere through the first exhaust shaft 12 with the closed switchgear 21 and open switchgear 18, and when simulating vacuum pressures in the thermal vacuum chamber 14 with closed switchgear 18 and open switchgear 21 is directed to the gas outlet system 2.

To ensure transient modes of operation of the gas generator 16 (injectivity or discharge of gas) and maintain a constant value of the total pressure at the inlet to the gas generator 16, air is bypassed from the receiver 9 using the bypass pipeline 7 with open switchgear 22, 23 and closed switchgear 19 into the outlet system 11 air in the case of a pressure depression in the receiver 9 or with open switchgear 19, 22 and closed switchgear 23 into the second exhaust shaft 13 so that with the injectivity of the gas generator 16, the bypass of the air flow rate from the receiver 9 into the atmosphere decreases, and when the gas of the gas generator 16 is released, the bypass of the air flow from the receiver 9 into the atmosphere increases. To maintain a constant value of P * _VX in transient operating modes of the gas generator 16, maintain a constant air flow through the receiver 9 as the sum of the air flow through the gas generator 16 and through the bypass pipeline 7.

In the case of testing the gas generator 16 when simulating the steady-state modes of operation of the turbofan engine, in a particular case, the closed switchgear 22 is closed, and in an emergency when the receiver 9 is pressurized, the closed switchgear 22 and 19 are opened, and the closed switchgear 23 is closed.

In the case of imitation of the test conditions for the gas generator 16 of a turbojet engine with LPC without retaining stages with mixing flows and a common jet nozzle (double-circuit engines of the AL-31F, RD-33 type), air is supplied to the inlet of the receiver 9 to the inlet to the gas generator 16 using the movable part 34 of the inlet device 3 with parameters equal to the decelerated parameters behind the LPC of the turbojet engine

R * _BX - R * _KND , T * _BX = T * _KND .

In this case, the structure of the gas generator 16 can in a particular case also include an external annular simulator of the external circuit channel (LSC) of the turbofan engine with a common supply of air flow from the movable part 34 of the inlet device 3 to the inlet to the gas generator 16 and to the LCC.

Air supply in relation to the tests of the gas generator 16 turbofan engines with retaining stages LPC with a common nozzle (turbofan engines of the PS-90 type) and with separate circuits (turbofan engines of the PD-14 type) to ensure the simulation of the thermal and strength state of the structure of the gas generator 16, including the radial clearances in the working blades of the compressor and turbine, produced separately through the supply pipeline 5 with parameters equal to the inhibited parameters behind the pressure stages of the LPC of the turbojet engine

P * _BX = P * _KND , T * _BX = T * _KND ,

and through the additional pipeline 42 to the technological channel 8 of the external circuit of the engine with parameters equal to the inhibited parameters behind the fan LPC of the turbojet engine

P * _KNK = P * _B , T * _KNK = T * _B , where

R * _KNK - total air pressure in the process channel 8 of the outer circuit of the turbofan engine;

Р * _В - total air pressure behind the fan LPC TRDD;

T * _KNK - retarded air temperature in the process channel 8 of the outer circuit of the turbofan engine;

Т * _В is the retarded air temperature behind the fan of the LPC of the turbofan engine, while the air flow in the pipeline 42 is regulated by means of the closed switchgear 43.

FIG. 5 shows the area of testing the gas generator in the coordinates of the operation of the turbojet engine in height (H) and the number (M _P ) of the flight Mach as part of a subsonic aircraft at the declared stand in comparison with the closest analogue (RU 2622588, 2017).

Thus, the declared stand for testing the gas generator of a turbojet by-pass engine makes it possible to ensure the complexity of testing the strength characteristics and gas-dynamic compliance of the gas generator units:

- in an extended range of operating conditions of a gas generator as part of a turbojet engine in terms of altitude and flight Mach number according to total pressure Р * _ВХ , decelerated temperature Т * _ВХ and static pressure Р _B at the stand;

- on transient operating modes (injectivity, gas discharge, etc.);

- when simulating the thermal state of the gas generator structure by simulating the conditions for supplying air to the gas generator, both according to the LPC scheme with retaining stages, and without retaining stages.

Claims (2)

1. A stand for testing a gas generator of a turbojet bypass engine, containing an air supply system, a gas exhaust system, an inlet device, an exhaust device, an inlet, exhaust and bypass air pipelines, and the exhaust and bypass pipelines are equipped with shut-off and control devices, the first outlet of the air supply system is communicated with a supply pipeline, and the inlet of the gas exhaust system is connected to the exhaust pipeline, characterized in that it is additionally equipped with a technological channel of the external engine circuit, a receiver, a device for leveling the air flow, an air exhaust system, two exhaust shafts and a thermal pressure chamber with a dynamometric platform located inside it, intended for installation of the tested gas generator, while the exhaust device includes a series-connected ejector-gas conduit, an exhaust diffuser and a gas-water cooler, the supply air pipeline is equipped with a locking and regulating device, the inlet device contains a stationary part and a movable part intended for connection with the gas generator inlet, a device for leveling the air flow is installed in front of the first outlet of the receiver, the exhaust device is installed at the outlet of the thermal pressure chamber and communicated with the inlet of the gas removal system by means of an exhaust pipeline, the supply pipeline is in communication with the inlet of the receiver , the first outlet of the receiver is connected to the inlet through the nozzle, the second outlet of the receiver is in communication with the inlet of the air exhaust system by means of a bypass pipeline, and the exhaust shafts are connected, respectively, with the exhaust and bypass pipelines and are equipped with shut-off and control devices. 2. The stand according to claim 1, characterized in that an additional pipeline with a shut-off control device is installed at the second outlet of the air supply system, and the outlet of the additional pipeline is equipped with a flow manifold and a flexible bellows, the outlet of which is connected to the process channel of the external engine circuit.

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