Aero-engine test stand ejection system and adjustment method

Abstract

The application discloses an aero-engine test stand injection system and a regulating method, relates to the technical field of aero-engine test stands, and solves the problem that the test stand injection system is difficult to adapt to the change of exhaust characteristics and test working conditions of different types of engines. The first-stage injection pipe, the second-stage injection pipe and the third-stage injection pipe are sequentially and slidably arranged on the slide rail, and the distance between the first-stage injection pipe, the second-stage injection pipe and the third-stage injection pipe is adjusted by the distance adjusting device; the inlet end of the first-stage injection pipe is detachably provided with a replaceable flow guide cover, the replaceable flow guide cover is provided with a flow guide block, and the flow guide block is provided with a nozzle; and the inlet end of the second-stage injection pipe and the third-stage injection pipe is provided with a flow guide cover. The application is designed in cooperation with the modular replaceable flow guide cover and the multi-stage dynamic adjustable injection pipe, and realizes the self-adaptive matching of the injection system to different engine exhaust flow, temperature and pressure.

Description

Technical Field

[0001] This invention relates to the field of aero-engine test stand technology, specifically to an aero-engine test stand ejector system and adjustment method. Background Technology

[0002] When an aero-engine is tested in a U-shaped test stand, the high-temperature exhaust gas passes through the ejector tube, the diffuser, and the exhaust tower before being discharged outside the test stand. At the same time, the exhaust kinetic energy of the high-temperature, high-speed exhaust gas draws a large amount of cold air into the ejector tube through the test chamber to mix thoroughly with the high-temperature exhaust gas, thereby achieving cooling and dilution and back pressure regulation. However, most existing test stands are fixed ejector systems, which are difficult to adapt to the exhaust characteristics and test conditions of different engine models. This results in problems such as large fluctuations in ejector efficiency, poor cooling uniformity, and low back pressure control accuracy. Summary of the Invention

[0003] To address the aforementioned problem that existing test stand ejector systems are ill-suited to adapting to varying exhaust characteristics and test conditions of different engine models, this invention proposes a new aero-engine test stand ejector system and its adjustment method. This invention achieves adaptive matching of the ejector system to different engine exhaust flow rates, temperatures, and pressures through a modular, replaceable fairing and a multi-stage dynamically adjustable ejector tube design.

[0004] This invention proposes an ejector system and adjustment method for an aero-engine test stand, specifically including a primary ejector tube, a secondary ejector tube, a tertiary ejector tube, a slide rail, and a distance adjustment device; the primary, secondary, and tertiary ejector tubes are slidably arranged on the slide rail in sequence, and the distance adjustment device adjusts the distance between the primary, secondary, and tertiary ejector tubes; a replaceable deflector is detachably provided at the inlet end of the primary ejector tube; deflectors are provided at the inlet ends of the secondary and tertiary ejector tubes.

[0005] Furthermore, wedge-shaped blocks are provided on the outer side of the outlet ends of the primary ejector tube and the secondary ejector tube.

[0006] Furthermore, the inclination angle of the wedge block is the same as the root angle of the inlet end guide shroud of the next stage ejector tube.

[0007] Furthermore, the inclined surface of the wedge block is provided with a high-temperature resistant sealing gasket.

[0008] Furthermore, each of the primary ejector tube, secondary ejector tube, and tertiary ejector tube is provided with a fixed bracket below it, and the fixed bracket is slidably connected to the slide rail.

[0009] Furthermore, the distance adjustment device includes two electric push rods and two servo motors. A servo motor is installed on the fixing bracket of the secondary ejector tube and the tertiary ejector tube. One end of one electric push rod is connected to the fixing bracket of the primary ejector tube, and the other end is connected to the servo motor below the secondary ejector tube. One end of the other electric push rod is connected to the fixing bracket of the secondary ejector tube, and the other end is connected to the servo motor below the tertiary ejector tube.

[0010] Furthermore, the replaceable air deflector has several spiral-shaped air deflector blocks on its windward side.

[0011] Furthermore, the replaceable flow guide and the flow guide block have a flow channel embedded inside, and the flow guide block is provided with a nozzle, which is connected to the flow channel.

[0012] Furthermore, the three-stage ejector tube is equipped with a differential pressure sensor, a thermocouple temperature sensor, and a flue gas analyzer.

[0013] An adjustment method for the ejector system of the aforementioned aero-engine test stand includes the following steps: After the aero-engine is started and tested, the pressure difference between the inside and outside of the third-stage ejector tube is measured. The distance between the first-stage ejector tube and the second-stage ejector tube is separated by the distance adjustment device to increase the ejector air intake and ensure that the negative pressure inside the ejector tube is greater than -200Pa. After the secondary ejector tube reaches the limit, the negative pressure value inside the ejector tube is continuously monitored. If the negative pressure is still lower than -200Pa, the distance between the secondary ejector tube and the tertiary ejector tube is adjusted by the distance adjustment device to adjust the ejector air intake. If the negative pressure is still below -200Pa after the third-stage ejector tube reaches the limit, the central control console will display an alarm, and the aircraft engine will brake and reduce power. By adjusting the intake air volume of the ejector tube, the negative pressure inside the ejector tube reaches the design threshold. At the same time, the exhaust gas temperature is detected, the spacing between each stage of the ejector tube is adjusted, and coolant is sprayed to ensure that the exhaust gas temperature is stable below 300℃. If the negative pressure remains below -200Pa or the temperature exceeds 300℃ after the third-stage ejector reaches its limit, the central control console will display an alarm. At the same time, the aircraft engine will brake and reduce power. After the engine comes to a complete stop, the problem will be identified and addressed.

[0014] The beneficial effects of the aero-engine test stand ejector system and adjustment method described in this invention are as follows: (1) The ejector system and adjustment method of the test stand of the aero-engine described in this invention are provided in which multi-stage ejector tubes are slidably set on the slide rail, and the distance between each stage of ejector tubes is adjusted by the distance adjustment device, thereby adjusting the air intake of the ejector tubes; through the multi-stage dynamic adjustable ejector tube structure composed of multi-stage ejector tubes and distance adjustment device and the modular replaceable fairing, the PID dual-loop collaborative control strategy is assisted to realize the millisecond-level response and precise coupling adjustment of the three parameters of exhaust back pressure, temperature and composition; and realize the adaptive matching of the ejector system to different engine exhaust flow rate, temperature and pressure.

[0015] (2) The ejector system and adjustment method of the aero-engine test stand described in this invention are provided with wedge blocks on the outside of the outlet end of the first-stage ejector tube and the second-stage ejector tube, and high-temperature resistant sealing gaskets are provided on the wedge blocks, so that dynamic compression sealing is achieved between the first-stage ejector tube and the second-stage ejector tube, and between the second-stage ejector tube and the third-stage ejector tube. This sealing structure can ensure that there is no leakage when the high-temperature gas flows through the ejector tubes at each stage are not separated, and at the same time adapt to the small displacement caused by thermal expansion.

[0016] (3) The aero-engine test stand ejector system and adjustment method described in this invention, by setting a number of guide blocks on a replaceable guide shield, and setting a number of nozzles on the guide blocks, the guide blocks cause the low-temperature air injected into the ejector tube to form a controllable vortex when passing through the guide blocks, thereby enhancing the airflow mixing efficiency. This ensures that the airflow accelerates smoothly along the axial direction, and guides the high-temperature exhaust gas to fully mix with the coolant sprayed from the atomizing nozzle through centrifugal force, thereby further reducing the exhaust gas temperature. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0018] In the attached diagram: Figure 1 This is a schematic diagram of the structure of an aero-engine test stand ejector system according to the present invention; Figure 2 This is a front view of an aero-engine test stand ejector system according to the present invention; Figure 3 The present invention relates to an ejector system for an aero-engine test stand. Figure 2 Cross-sectional view at point AA; Figure 4 The present invention relates to an ejector system for an aero-engine test stand. Figure 3 A magnified view of a section at point A1; Figure 5 The present invention relates to an ejector system for an aero-engine test stand. Figure 2 Cross-sectional view at point BB; Figure 6 This is a structural schematic diagram of a replaceable fairing for an aero-engine test stand ejector system according to the present invention. Figure 7 This is a front view of a replaceable fairing for an aero-engine test stand ejector system according to the present invention. Figure 8 This is a flowchart of an adjustment method for an aero-engine test stand ejector system according to the present invention; Among them: 1-replaceable flow guide, 2-first stage ejector tube, 3-second stage ejector tube, 4-third stage ejector tube, 5-fixed bracket, 6-slide rail, 7-electric push rod, 8-servo motor, 9-high temperature resistant sealing gasket, 10-flow guide block, 11-wedge block, 12-flow guide. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other. The described embodiments are merely some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] Specific implementation method one: See Figures 1-8 This embodiment is described in detail. The aero-engine test stand ejector system and adjustment method described in this embodiment specifically includes a primary ejector tube 2, a secondary ejector tube 3, a tertiary ejector tube 4, a slide rail 6, and a distance adjustment device. A fixed bracket 5 is provided below each of the primary ejector tube 2, secondary ejector tube 3, and tertiary ejector tube 4, and the lower end of the fixed bracket 5 is slidably connected to the slide rail 6. In the initial state, the primary ejector tube 2, secondary ejector tube 3, and tertiary ejector tube 4 are sequentially connected. The distance adjustment device adjusts the distance between the primary ejector tube 2, secondary ejector tube 3, and tertiary ejector tube 4. A replaceable flow deflector 1 is detachably provided at the inlet end of the primary ejector tube 2. The replaceable flow deflector 1 and the primary ejector tube... The ejector tube 2 is connected via a flange, with a flexible graphite composite gasket embedded between the flange faces, and secured with high-temperature alloy bolts to ensure connection strength and sealing reliability. Since the exhaust nozzle sizes of different aero-engine models vary, the replaceable deflector 1 at the front end of the ejector system can be designed with different structures to meet the testing requirements of different aero-engine models. For example, deflectors corresponding to three typical exhaust nozzle diameters: Φ800mm, Φ1000mm, and Φ1200mm. Different diameter deflectors can perfectly adapt to different engine models, effectively preventing exhaust gas leakage and airflow disturbance while improving ejection efficiency. Deflectors 12 are fixedly installed at the inlet ends of the secondary ejector tube 3 and the tertiary ejector tube 4.

[0021] A wedge-shaped block 11 is provided on the outer side of the outlet end of the primary ejector tube 2 and the secondary ejector tube 3. The inclination angle of the wedge-shaped block 11 is consistent with the root angle of the guide shroud 12 at the inlet end of the next-stage ejector tube. A high-temperature resistant sealing gasket 9 is provided on the inclined surface of the wedge-shaped block 11. The primary ejector tube 2 and the secondary ejector tube 3, as well as the secondary ejector tube 3 and the tertiary ejector tube 4, are dynamically pressed and sealed by the high-temperature resistant sealing gasket 9. This sealing structure can ensure that there is no leakage when the high-temperature gas flows through the tubes without separation, and at the same time, it can accommodate the small displacement caused by thermal expansion.

[0022] The fixed bracket 5 is designed with a box-shaped cross-section structure and built-in reinforcing ribs to improve bending stiffness. At the same time, considering the coupling effect of thermal expansion and vibration, the bottom of the fixed bracket 5 is embedded with a self-lubricating ceramic slider. The two slide rails 6 are made of high-nickel alloy with nitriding surface treatment and are pre-embedded in the concrete base to ensure that there is no jamming, micro-settlement and thermal deformation mismatch under long-term operation. The ceramic slider is slidably set on the slide rails 6.

[0023] The adjusting device includes two electric push rods 7 and two servo motors 8. A servo motor 8 is installed on the fixing brackets 5 of both the secondary ejector tube 3 and the tertiary ejector tube 4. The front ends of the electric push rods 7 are flange-type. One end of one electric push rod 7 is connected to the fixing bracket 5 of the primary ejector tube 2, and the other end is connected to the servo motor 8 below the secondary ejector tube 3. One end of the other electric push rod 7 is connected to the fixing bracket 5 of the secondary ejector tube 3, and the other end is connected to the servo motor 8 below the tertiary ejector tube 4. The adjusting device enables independent displacement control of the two ejector tubes. When it is necessary to adjust the opening between the various pressure tubes, the servo motors 8 precisely drive the electric push rods 7 to extend and retract, changing the length of the annular channel between the ejector tubes in real time. The control system... Figure 8 The startup logic flow shown is used to stably achieve dynamic matching of ejection parameters.

[0024] The replaceable air deflector 1 has several spiral-shaped air guide blocks 10 on its windward side. The air guide blocks 10 can be arranged in specific angles and quantities according to different diameter air deflectors. The spiral angle of the air guide blocks 10 is 15° to 22°. Flow channels are embedded inside the replaceable air deflector 1 and the air guide blocks 10. Nozzles are provided on the air guide blocks 10, and the nozzles are connected to the flow channels. The nozzles spray coolant towards the center of the vortex. Driven by the high-temperature, high-speed exhaust gas, the low-temperature air injected into the ejector tube forms a controllable vortex when passing through the air guide blocks 10, enhancing the airflow mixing efficiency. This ensures that the airflow accelerates smoothly along the axial direction and guides the high-temperature exhaust gas to fully mix with the coolant sprayed from the atomizing nozzle through centrifugal force, further reducing the exhaust gas temperature.

[0025] The surface of the guide block 10 is coated with a ceramic-based composite coating, which can withstand temperatures up to 1100℃, ensuring long-term service stability. At the same time, the guide block 10 integrates an atomization channel, which is linked with the control system. When the exhaust gas temperature exceeds the preset threshold or the flue gas analyzer detects abnormal components, the high-pressure atomization pump is automatically triggered to spray deionized water into the vortex core area with a particle size of 50μm through a microporous nozzle. This achieves transient cooling and synergistic capture of pollutants. The atomized water vapor rapidly vaporizes and absorbs heat in the high-temperature zone, reducing the generation rate of nitrogen oxides.

[0026] The three-stage ejector tube 4 is equipped with a differential pressure sensor, a thermocouple temperature sensor, and a flue gas analyzer. These sensors are staggered along the circumference of the three-stage ejector tube 4 and precisely point to the axis. The data sampling frequency reaches 100Hz and is uploaded to the central control console in real time via a fiber optic link. Combined with a dual-loop PID algorithm, the ejector parameters are dynamically optimized to ensure stable exhaust back pressure, uniform temperature field, and controllable combustion product composition during the test run. The sensor probes all adopt a double-layer vacuum insulation structure, and the detection position is 3 to 5 times the tube diameter from the inlet end of the three-stage ejector tube 4 to ensure that the measurement point is in the fully developed turbulent core region, effectively avoiding boundary layer interference and improving data confidence.

[0027] This embodiment establishes a dual-loop PID control architecture. The inner loop uses pressure difference as the control target to quickly respond to ejector flow disturbances; the outer loop uses exhaust gas temperature as the control target to realize a method for adjusting the ejector system of an aero-engine test stand.

[0028] An adjustment method for the ejector system of the aforementioned aero-engine test stand includes the following steps: After the aero-engine is started and tested, the openings between the first-stage ejector 2 and the second-stage ejector 3, and between the second-stage ejector 3 and the third-stage ejector 4, are all set to 0%. The pressure difference between the inside and outside of the third-stage ejector 4 is measured using a differential pressure sensor. Based on the data fed back by the differential pressure sensor, the opening between the first-stage ejector 2 and the second-stage ejector 3 is first adjusted using the pitch control device to increase the ejector intake air volume so that the negative pressure inside the ejector approaches and is greater than -200 Pa. If the target is not achieved, the opening is gradually increased until it reaches 80%. After the secondary ejector tube 3 reaches the limit, the negative pressure value inside the ejector tube is continuously monitored. If the negative pressure is still lower than -200Pa, the opening between the secondary ejector tube 3 and the tertiary ejector tube 4 is adjusted synchronously through the distance adjustment device to adjust the ejector air intake until the negative pressure inside the ejector tube stabilizes at -200Pa±10Pa. If the negative pressure is still below -200Pa after the third-stage ejector tube 4 reaches the limit, the central control console will display an alarm, and the aircraft engine will brake and reduce power. By adjusting the intake air volume of the ejector tube, the negative pressure inside the ejector tube reaches the design threshold; the outer ring temperature control is activated, using the exhaust gas temperature fed back in real time by the thermocouple temperature sensor as input, driving the servo motor 8 to adjust the opening degree of each stage of the ejector tube, with the maximum opening degree limited to 95%. When the exhaust gas temperature is ≥300℃, the outer ring triggers the atomization cooling subroutine to maintain the exhaust gas temperature within the range of 300℃±5℃, thereby realizing dual-ring PID collaborative closed-loop control, ensuring dynamic coupling and high-precision synchronous response of exhaust back pressure and temperature dual parameters, and further adapting to the rapid switching requirements of different engine models, thrust levels and test conditions; If the negative pressure remains below -200Pa or the temperature exceeds 300℃ after the third-stage ejector tube 4 reaches its limit, the central control console will display an alarm. At the same time, the aircraft engine will brake and reduce power. After the engine stops completely, the problem will be identified and addressed.

[0029] If the temperature continues to exceed the limit or the flue gas analyzer detects NO... x Upon a sudden increase in concentration, the system immediately activates a tiered response mechanism: increasing the working pressure of the atomizing nozzle to 8 MPa, triggering a step-wise reduction in engine power, ensuring that the entire engine completes closed-loop control of both temperature and emissions indicators within 30 seconds, with a total response time of less than 25 seconds, and temperature fluctuations controlled within ±3℃. x The concentration decreased by 62.3%, and a three-level warning sign and corresponding report were simultaneously displayed on the central control panel to assist engineers in fault diagnosis.

[0030] In summary, the ejector system and adjustment method for an aero-engine test stand described in this invention involve multi-stage ejector tubes slidably mounted on slide rail 6. The spacing between each stage of ejector tubes is adjusted by a spacing adjustment device, thereby regulating the air intake volume of the ejector tubes. Through the multi-stage dynamically adjustable ejector tube structure composed of multi-stage ejector tubes and a spacing adjustment device, along with the modular replaceable fairing 1, and assisted by a PID dual-loop collaborative control strategy, millisecond-level response and precise coupling adjustment of the three parameters of exhaust back pressure, temperature, and composition are achieved. This enables the ejector system to adaptively match different engine exhaust flow rates, temperatures, and pressures.

[0031] The present invention discloses an ejector system and adjustment method for an aero-engine test stand. A wedge block 11 is provided on the outer side of the outlet end of the first-stage ejector tube 2 and the second-stage ejector tube 3. A high-temperature resistant sealing gasket 9 is provided on the wedge block 11, so that dynamic compression sealing is achieved between the first-stage ejector tube 2 and the second-stage ejector tube 3, and between the second-stage ejector tube 3 and the third-stage ejector tube 4. This sealing structure can ensure that there is no leakage when the high-temperature gas flows through the ejector tubes at each stage are not separated, and at the same time, it can adapt to the small displacement caused by thermal expansion.

[0032] The present invention discloses an ejector system and adjustment method for an aero-engine test stand. By setting a plurality of guide blocks 10 on a replaceable guide shield 1, and setting a plurality of nozzles on the guide blocks 10, the guide blocks 10 cause the low-temperature air injected into the ejector tube to form a controllable vortex when passing through the guide blocks 10, thereby enhancing the airflow mixing efficiency. This ensures that the airflow accelerates smoothly along the axial direction, and guides the high-temperature exhaust gas to fully mix with the coolant sprayed from the atomizing nozzles through centrifugal force, thereby further reducing the exhaust gas temperature.

[0033] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the invention. They can also be reasonable combinations of the features described in the above embodiments. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An ejector system for an aero-engine test stand, characterized in that: It includes a primary ejector tube (2), a secondary ejector tube (3), a tertiary ejector tube (4), a slide rail (6), and a distance adjustment device; the primary ejector tube (2), the secondary ejector tube (3), and the tertiary ejector tube (4) are slidably arranged on the slide rail (6) in sequence, and the distance adjustment device adjusts the distance between the primary ejector tube (2), the secondary ejector tube (3), and the tertiary ejector tube (4); the inlet end of the primary ejector tube (2) is detachably provided with a replaceable flow guide (1); the inlet ends of the secondary ejector tube (3) and the tertiary ejector tube (4) are provided with flow guides (12).

2. The ejector system for an aero-engine test stand according to claim 1, characterized in that: A wedge-shaped block (11) is provided on the outer side of the outlet end of the primary ejector tube (2) and the secondary ejector tube (3).

3. The ejector system for an aero-engine test stand according to claim 2, characterized in that: The inclination angle of the wedge block (11) is the same as the root angle of the guide shroud (12) at the inlet end of the next stage ejector tube.

4. The aircraft engine test stand ejector system according to claim 3, characterized in that: The inclined surface of the wedge block (11) is provided with a high-temperature resistant sealing gasket (9).

5. The ejector system for an aero-engine test stand according to claim 1, characterized in that: A fixed bracket (5) is provided below each of the primary ejector tube (2), the secondary ejector tube (3) and the tertiary ejector tube (4), and the fixed bracket (5) and the slide rail (6) are slidably connected.

6. The ejector system for an aero-engine test stand according to claim 5, characterized in that: The distance adjustment device includes two electric push rods (7) and two servo motors (8). A servo motor (8) is installed on the fixed bracket (5) of the secondary ejector tube (3) and the tertiary ejector tube (4). One end of one electric push rod (7) is connected to the fixed bracket (5) of the primary ejector tube (2), and the other end is connected to the servo motor (8) below the secondary ejector tube (3). One end of the other electric push rod (7) is connected to the fixed bracket (5) of the secondary ejector tube (3), and the other end is connected to the servo motor (8) below the tertiary ejector tube (4).

7. The ejector system for an aero-engine test stand according to claim 1, characterized in that: The replaceable air deflector (1) has several spiral-shaped air deflector blocks (10) on its windward side.

8. The ejector system for an aero-engine test stand according to claim 7, characterized in that: The replaceable flow guide (1) and the flow guide block (10) are internally provided with flow channels, and the flow guide block (10) is provided with nozzles, which are connected to the flow channels.

9. The ejector system for an aero-engine test stand according to claim 1, characterized in that: The three-stage ejector tube (4) is equipped with a differential pressure sensor, a thermocouple temperature sensor and a flue gas analyzer.

10. An adjustment method for the ejector system of the aero-engine test stand as described in claim 1, characterized in that: Includes the following steps: After the aero-engine is started and tested, the pressure difference between the inside and outside of the third-stage ejector tube (4) is obtained. The distance between the first-stage ejector tube (2) and the second-stage ejector tube (3) is separated by the distance adjustment device and the distance is adjusted to increase the ejector air intake and ensure that the negative pressure inside the ejector tube is greater than -200Pa. After the secondary ejector tube (3) reaches the limit, the negative pressure value inside the ejector tube is continuously monitored. If the negative pressure is still lower than -200Pa, the distance between the secondary ejector tube (3) and the tertiary ejector tube (4) is adjusted by adjusting the distance device to adjust the ejector air intake. If the negative pressure is still below -200Pa after the third-stage ejector tube (4) reaches the limit, the central control console will display an alarm and the aircraft engine will brake and reduce power. By adjusting the intake air volume of the ejector tube, the negative pressure inside the ejector tube reaches the design threshold. At the same time, the exhaust gas temperature is detected, the spacing between each stage of the ejector tube is adjusted, and coolant is sprayed to ensure that the exhaust gas temperature is stable below 300℃. If the negative pressure is still below -200Pa or the temperature exceeds 300℃ after the third-stage ejector tube (4) reaches the limit, the central control console will display an alarm. At the same time, the aircraft engine will brake and reduce power. After the engine stops completely, the problem will be identified and dealt with.

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