RU2467302C1 - Altitude test bench for double-flow jet turbine engines, and its operating method (versions) - Google Patents

Abstract

FIELD: test equipment.

SUBSTANCE: invention refers to testing of jet turbine engines using the test bench under conditions close to flight conditions. Altitude test bench for double-flow jet turbine engines includes thermostatic and exhausting plants, and thermal vacuum chamber with the engine to be tested, which is arranged inside it. Engine is installed on fixed posts of dynamometric platform. Air path of the tested engine is interconnected with thermal vacuum chamber inlet through controlled throttles. The cavity inside thermal vacuum chamber is separated with a partition installed in engine exhaust zone and equipped with bypass valves. Thermal vacuum chamber is equipped with supply pipelines from high-altitude line with external throttles. Throttles are connected to receiver rigidly fixed on dynamometric platform. Receiver outlet is connected to the tested engine inlet through lemniscate head piece and flow metering manifold. Engine nozzle is installed with a radial gap and low axial crossover inside exhaust pipeline with an ejecting head piece. The above head piece is fixed on a partition wall. Pipeline connected to the receiver is provided with external bypass throttle to supply the delivery air from thermal vacuum chamber inside the receiver. The other object of this invention is operating method of the above described bench, which consists in the fact that air from thermostatic and exhausting plant is supplied to pipeline from high-altitude line; low pressure pipeline is shut-off to minimum required air flow rate; receiver bypass throttle is closed; at that, air is supplied through an elbow to receiver, then through lemniscate head piece, flow metering manifold to the tested engine inlet; the gas entering the compartment is pumped off with the exhausting plant. The other bench operating method consists in the fact that air is supplied from thermostatic and exhausting plant to low pressure pipeline; high pressure pipeline is shut-off, and the pipeline is fully opened so that the air can enter the inlet compartment; bypass throttle from receiver is opened and air is supplied through lemniscate head piece, flow metering manifold, engine, exhaust pipeline with further pumping of air from outlet compartment by means of exhausting plant.

EFFECT: invention allows improving thrust measurement accuracy.

3 cl, 1 dwg

Description

The invention relates to the field of testing turbojet engines on a stand in conditions close to flight.

Reproduction of high-speed and climatic conditions is an integral part of bench tests carried out in the process of creating and improving gas turbine engines. Tests to determine the throttle and high-speed characteristics, as well as tests to assess the operational characteristics of the engine, primarily its starting properties, are the basis of the work performed on the stand.

The first type of test is carried out, as a rule, in a pressure chamber (TAC) of a high-altitude stand according to a scheme with an attached air duct, the second - on a climatic stand or in a TAC according to a scheme with a dividing partition.

A technical solution is known comprising a pressure chamber with a test engine, refrigeration and exhauster units. A return pipe is installed from the exhaust diffuser to the engine inlet with a throttle and an injector located in it that regulate the set parameters and air flow of the second circuit (AS No. 249002 of March 20, 1968, according to class G01M, “Stand for high-altitude testing double-circuit turbojet engines ”- analogue). However, the disadvantage of this device is that it is bulky, overloaded with auxiliary equipment, requires significant energy costs, and also does not provide self-regulation of the gas-air circuit of the TAC, which reduces the failure of the simulated speed during startup.

For engines with a radial inlet, instead of a pipeline at the inlet, a partition is used that divides the internal cavity of the TAC into two compartments - compressor and power (patent No. 2336514 dated 10.10.2008, IPC G01M 15/14, “Method for high-altitude testing of turbofan engines and a stand for its implementation "), which describes a method for high-altitude testing of dual-circuit turbojet engines, which consists in starting the test engine, supplying air from the thermostatic unit and secondary air to its inlet, its flow rate, output g the basics of the primary circuit path by an exhauster unit, air bypass into the TAC from the air path with the formation of front zones with flowing through the front partition, thermostatting of the test engine with subsequent starting. This is ensured by a high-altitude test bench containing a thermostatic, exhauster unit, TAC with an engine, while the output of the second circuit of the engine is separated from the gas path of its first circuit with the possibility of air bypass into the pressure chamber, and the TAC cavities are separated by partitions installed in the area of the engine input device and in the zone of its exit, the front partition has adjustable holes, and the rear bypass valves.

However, the measurement accuracy of the tested engine is insufficient, since the power decoupling of the engine mounts from the dynamometer platform serving the TAC is not ensured, and most importantly, to expand the range of simulated heights and speeds during testing while maintaining the existing energy of the high-altitude compressor station.

A technical solution is also known (Russian patent No. 2336514 dated 10.20.2008, IPC G01M 15/00) for high-altitude testing of turbofan engines with a thermostatic, exhauster installation, a pressure chamber with a test engine located inside it, in which the internal cavity of the pressure chamber is divided by the front and rear baffles, respectively installed in the area of the input device of the test engine and in the area of its exhaust, while the front baffle is equipped with adjustable holes, and the rear burnout The odka has bypass valves.

However, the main disadvantage of this device is that it does not provide the definition of throttle and altitude-speed characteristics.

The aim of the invention is to increase the accuracy of thrust measurement and reduce costs when testing aircraft engines in high-speed and climatic conditions, to expand the range of simulated high-climatic conditions, which will allow switching from a circuit with a dividing partition to a circuit with an attached pipeline without carrying out installation work.

The combined circuit with adjustable bypass from the receiver is a combination of circuits with a dividing wall and with an attached air duct. This scheme extends the range of reproducible high-speed conditions in the TAC. The combined circuit is characterized by self-regulation of the gas-air flow of the TAC circuit, which simplifies the maintenance of the simulated speed when checking the starting properties of the engine and in transient conditions.

The design tasks are solved in that the stand is made in the form of a stand for high-altitude testing of turbofan engines. The stand contains a thermostatic and an exhauster unit, a pressure chamber and a test engine located inside it, mounted on fixed racks on a dynamometer platform, while the air path of the circuit of the test engine is in communication with the temperature chamber entrance through an adjustable hole, the internal cavity of the pressure chamber is divided by a partition installed in the engine exhaust area and equipped with bypass valves.

According to the invention, the pressure chamber is equipped with a supply pipe with an external choke from a high-altitude line and is connected through a knee to a receiver rigidly mounted on a dynamometer platform, the output of which is coaxially connected through a lemniscate nozzle and a flow collector with the input of the test engine, the nozzle of which is installed with a radial clearance and a small axial overlap inside the exhaust pipe with an ejection nozzle mounted on a dividing wall, while the supply pipe with an external core it is connected to the bypass throttle pipe for passage of forced air entering the receiver from the external pipeline into the pressure chamber.

The tasks set for the operating conditions of the stand according to the scheme with the connected pipeline are solved in such a way that the stand operates so that air from the thermostatic and exhauster units with excess pressure is supplied to the pipeline from the high-altitude line (8), the low-pressure pipeline (11) is closed to the minimum required air flow for blowing the test engine when it flows from the input compartment (9) to the output compartment (1) through the differential choke (14), the bypass choke from the receiver (10) is closed, while the air through to Leno enters the receiver (7) located inside the compartment (9), from where, through the lemniscate nozzles (6), the flow collector (5) enters the input of the test engine (4) mounted on the dynamometer platform (12), and the nozzle of the test engine is installed with a radial clearance of 0.5 mm and axial overlap inside the exhaust pipe with an ejecting nozzle (3) mounted on a dividing wall (2), the gas entering the compartment (1) is pumped out by an exhauster unit.

For the operating conditions of the stand, according to the scheme with a dividing partition, they are used in such a way that the stand functions so that the air from the refrigeration and exhauster plants with excess pressure is supplied to the low pressure pipe (11), the pipeline (8) is closed and the pipeline (11) is completely opened for air to enter compartment (9) along the TAC axis, open the bypass throttle (10) from the receiver and then feed it through the lemniscate nozzles (6), the flow collector (5), the engine (4), the exhaust pipe with the ejecting nozzle (3) followed by pumping air from the compartment (1) with an exhauster unit, while the open throttle (14) provides the required air flow for blowing the test engine when it flows from the compartment (9) into the compartment (1).

For both variants of operation, a static pressure is set at the nozzle exit of the engine, which corresponds to a given flight altitude, and at the engine inlet, the total pressure corresponding to the specified values of the flight speed is set. The throttle control of the gas-air circuit outside and inside the TAC provides precise control of the required value of the simulated height and flight speed.

The drawing schematically shows a longitudinal section of the inventive bench for high-altitude testing of turbofan engines, a combined circuit with adjustable bypass from the receiver, which is a functional combination of circuits with a dividing wall and an attached air duct that implements two ways of functioning of the gas-air circuit inside the TAC. Such a combination allows the entire scope of tests to be carried out without changing the layout within the TAC.

The stand contains a circular pressure chamber, the inner chamber of which is divided by a partition 2 into two compartments 1 (second compartment) and 9 (first compartment). In the first compartment, on the stationary racks 13 installed on the dynamometer platform 12, the test engine 4 is installed. On the same dynamometer platform in the compartment 9, a stationary receiver 7 is installed, the output of which through the lemniscate nozzles 6 is coaxially connected to the flowmeter manifold 5 and then to the input of the engine 4. The input of the receiver 7 is connected to the high pressure pipe 8 and the bypass throttle 10, the output connected to the compartment 9. The compartment 9 in the front axial part of the TAC is equipped with a low pressure pipe 11. The engine nozzle is installed Leno with a radial clearance of 0.5 mm and a small axial overlap inside the exhaust duct with entraining nozzle 3 mounted on the dividing wall 2. The separating partition 2 is provided with an outlet throttle 14. The stand has a thermostatic unit 16 and the exhauster 15 installation.

The inventive stand for high-altitude testing of dual-circuit turbojet engines works as follows.

The first option corresponds to a circuit with an attached pipeline. The air from the thermostatic and exhauster unit with excess pressure is supplied to the high pressure pipe 8. The low pressure pipe 11 is almost completely closed so as to ensure the minimum required air flow for blowing the engine when it flows from the input compartment 9 to the output compartment 1 through the bypass throttle 14. The bypass throttle from receiver 10 closes. As a result, air from the pipeline 8 through the "elbow" enters the receiver 7 located inside the compartment 9. From where, through the lemniscate nozzles 6, the flow collector 5 enters the inlet of the engine 4. The engine nozzle is installed with a radial clearance of 0.5 mm and a small axial overlap inside the exhaust pipeline with an ejection nozzle 3, mounted on the dividing wall 2. Expiring from the nozzle of the engine, the gas enters the compartment 1, where it is pumped out by an exhauster installation.

The second option corresponds to the scheme with a dividing partition. Air from the refrigeration and exhauster plants with excess pressure is supplied to the low pressure pipe 11 and enters the compartment 9. The high pressure pipe 8 is closed. The air inlet direction is along the TAC axis. The bypass throttle from receiver 10 opens. Air through an open bypass throttle enters the receiver 7 and then through a lemniscate nozzle 6, a flowmeter manifold 5, an engine 4, an exhaust pipe with an ejecting nozzle 3, is pumped out of the compartment 1 by an exhauster unit. The throttle 14 provides the minimum required air flow for blowing the engine when it flows from compartment 9 to compartment 1.

For both versions, a static pressure is set by cutting the nozzle of the engine, which corresponds to a given flight altitude, and by the engine input, the total pressure corresponding to the specified values of the flight speed. The control of the gas-air circuit chokes, namely the chokes of the pipelines 8 and 11 outside and the chokes 10 and 14 inside the TAC, provides precise control of the required value of the simulated height and flight speed.

Claims (3)

1. A test bench for high-altitude testing of turbofan engines with thermostatic and exhauster units, a pressure chamber with a test engine installed inside it, mounted on fixed racks on a dynamometer platform, while the air duct of the test engine is connected to the entrance to the pressure chamber through adjustable throttles, the internal cavity of the thermal bar divided by a partition installed in the exhaust area of the engine and equipped with bypass valves, characterized in that thermo the pressure chamber is equipped with inlet pipelines from a high-altitude line with external chokes connected to a receiver rigidly mounted on a dynamometer platform, the output of which is connected through a lemniscate nozzle and a flow collector to the input of the test engine, the nozzle of which is installed with a radial clearance and a small axial overlap inside the exhaust pipe with an ejector nozzle mounted on the dividing wall, while the pipeline leading to the receiver is supplemented by an external bypass throttle a volume for supplying injected air from the volume of the pressure chamber into the receiver. 2. The method of operation of the stand according to claim 1, which consists in the fact that air from a thermostatic and exhauster installation with excess pressure is supplied to the pipeline from a high-altitude line (8), the low-pressure pipeline (11) is closed to the minimum required air flow for blowing the test engine when it flows from the input compartment (9) to the output compartment (1) through the differential choke (14), the bypass choke from the receiver (10) is closed, while air through the elbow enters the receiver (7) located inside the compartment (9), where through lemnisca nozzle (6), flow collector (5) is fed to the input of the test engine (4) mounted on the dynamometer platform (12), and the nozzle of the test engine is installed with a radial clearance of 0.5 mm and axial overlap inside the exhaust pipe with an ejecting nozzle ( 3), mounted on the dividing wall (2), and the gas entering the compartment (1) is pumped out by an exhauster unit. 3. The method of functioning of the stand according to claim 1, which consists in the fact that air from a thermostatic and exhauster installation with excess pressure is supplied to a low pressure pipe (11), the pipe (8) is closed and the pipe (11) is completely opened for air to enter the inlet compartment (9) along the axis of the pressure chamber, open the bypass choke (10) from the receiver and then feed it through the lemniscate nozzles (6), the flow collector (5), the engine (4), the exhaust pipe with the ejecting nozzle (3), followed by pumping from the outlet compartment (1) air exhauster installation, while the open throttle (14) provides the required air flow for blowing the test engine when it flows from the input compartment (9) to the output compartment (1).

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