Testing device and method for measuring reverse jet flow interference force of aircraft main engine

Abstract

The invention discloses a test device and method for measuring reverse jet flow interference force of a main engine of an aircraft. Comprising a model body and a supporting rod used for installing the model body on a wind tunnel test section. The jet flow generator is detachably mounted at one end of the model main body, and the cold jet flow generator or the hot jet flow generator can be selected to be connected with the model main body according to requirements; the force measuring balance system comprises a first force measuring balance used for measuring thrust generated by the main engine and a second force measuring balance used for measuring pneumatic disturbing force borne by the model main body; the air supply system is used for supplying air to the jet flow generator; and the data acquisition system is used for synchronously acquiring output signals of the first force measuring balance and the second force measuring balance so as to realize independent measurement of the thrust of the main engine and the pneumatic disturbing force. The test device provided by the invention can be widely applied to aerodynamic force measurement under the condition of large high-low load difference, and provides high-precision test data support for the design of an aircraft control system under the reverse jet interference condition of a main engine.

Description

Technical Field

[0001] This invention relates to the field of aerodynamic ground simulation test technology, and in particular to a test device and method for measuring the force of reverse jet interference of the main engine of an aircraft. It is applicable to the accurate measurement of aerodynamic forces / torques of reusable rockets, return capsules and other vehicles facing aerodynamic interference problems caused by the reverse jet of the main engine. Background Technology

[0002] With the rapid development of reusable launch vehicles and reentry capsule recovery technologies, during the recovery process, the main engine undergoes reverse ignition at low altitude to generate thrust for deceleration and precise landing. At this time, the reverse jet stream from the high-thrust main engine interacts with the high-speed incoming airflow, creating a significant aerodynamic interference effect that directly impacts the aircraft's drag, lift, and stability. Accurately acquiring aerodynamic data under interference conditions is crucial for the safe flight of the aircraft.

[0003] Currently, research on the interference from the reverse jet of the main engine mainly relies on wind tunnel tests and numerical simulations. In existing wind tunnel testing techniques, a single force balance is typically used to support the model and measure the total aerodynamic force. However, under the condition of the main engine reverse jet being activated, the thrust of the main engine is much greater than the aerodynamic interference force (the difference between the two is nearly an order of magnitude). A single force balance cannot simultaneously ensure the measurement accuracy of high-load thrust and low-load interference force within the same range. It is also difficult to accurately decouple the reverse thrust generated by the jet from the interference force generated by the interaction between the jet and the incoming flow, which limits the in-depth understanding of the interference mechanism. Furthermore, cold / hot jet simulations usually require two systems, which are costly and time-consuming to switch between, making it difficult to interchange them under the same test model conditions.

[0004] Therefore, developing a wind tunnel test system for main engine reverse jet interference that can simultaneously meet the requirements of high fidelity, high efficiency, high precision measurement, and strong adaptability is of great theoretical and engineering significance for promoting the advancement of reusable rocket aerodynamic design. Summary of the Invention

[0005] The purpose of this invention is to provide a test device and method for measuring the force of reverse jet interference of the main engine of an aircraft, so as to solve the problem of insufficient measurement accuracy caused by the large difference between the thrust of the main engine of the aircraft and the aerodynamic interference force in the prior art, and to realize the interchangeable simulation of cold spray and hot spray conditions.

[0006] This invention provides a test apparatus for measuring the force of reverse jet interference from an aircraft main engine, comprising: The main body of the model has an internal cavity for accommodating equipment. A support rod, connected to the main body of the model, is used to install the main body of the model in the wind tunnel test section; A jet generator is detachably installed at one end inside the model body. The jet generator includes a cold jet generator and a hot jet generator. The cold jet generator or the hot jet generator can be selected to be connected to the model body according to the simulation requirements. The force balance system includes a first force balance and a second force balance installed inside the model body. One end of the first force balance is connected to the jet generator and the other end is connected to the support rod, and it is used to measure the thrust generated by the main engine. The second force balance is sleeved on the outside of the support rod and is used to measure the aerodynamic interference force on the model body. An air supply system is used to supply air to the jet generator; The data acquisition system is used to simultaneously acquire the output signals of the first force balance and the second force balance, so as to realize the independent measurement of the main engine thrust and aerodynamic interference force.

[0007] Furthermore, the gas supply system includes a gas supply pipeline that passes through the support rod, the first force balance, and is connected to the jet generator; the gas supply pipeline and the jet generator are connected by a thread.

[0008] Furthermore, the jet generator and the first force balance are fitted with cylindrical surfaces and connected by pins; and when the jet generator and the first force balance are installed, a gap must be maintained between them and the model body to ensure that the jet generator does not contact the model body when it is turned on.

[0009] Furthermore, the cold jet generator uses room temperature high-pressure air as the jet medium and simulates different thrust conditions by adjusting the air supply pressure.

[0010] Furthermore, the thermal jet generator is a gas generator used to simulate the start-up state of a real engine.

[0011] Furthermore, the first force balance and the second force balance are spatially decoupled to avoid load transfer and measurement crosstalk, ensuring accuracy within their respective measurement ranges.

[0012] Furthermore, the jet generator has a nozzle at its front end and a jet reservoir inside for stabilizing the jet pressure. A pressure sensor is provided on the front end face of the jet generator for measuring the pressure in the jet reservoir. The nozzle is opposite to the direction of the incoming flow, forming a reverse jet.

[0013] Furthermore, the end of the support rod furthest from the first force balance extends outside the model body.

[0014] This invention provides a test method for measuring the force of reverse jet interference from an aircraft main engine, based on the aforementioned test apparatus, comprising the following steps: S1. Select a cold jet generator or a hot jet generator according to the test requirements and install it inside the front end of the model body; S2. Install the main body of the model on the wind tunnel test section using support rods, and connect the air supply pipeline and data acquisition cable; S3. Calibrate the first and second force balances to determine their measurement accuracy; S4. Start the wind tunnel, adjust the incoming Mach number to the target operating condition, and turn on the jet generator after the flow field stabilizes; S5. The data acquisition system synchronously acquires the output signals of the first and second force balances to obtain the thrust data of the main engine and the aerodynamic disturbance force data of the model body; S6. Change the jet pressure ratio and the angle of attack of the main body of the model to carry out multi-condition combination tests; S7. Analyze the test data and evaluate the impact of the reverse jet on the overall aerodynamic performance of the aircraft.

[0015] Furthermore, under the same aerodynamic shape and incoming flow conditions, comparative tests were conducted on cold spray and hot spray conditions to study the influence of the hot spray flow effect on aerodynamic interference characteristics.

[0016] In summary, compared with the prior art, the present invention has the following advantages: The experimental apparatus provided by this invention employs a dual-force balance system to independently measure the thrust of the main engine and the aerodynamic interference force experienced by the model body. This solves the problem of insufficient measurement accuracy of a single balance due to large differences in load, and significantly improves the measurement resolution of minute interference forces. The jet generator at the front end of the model body adopts a replaceable design, supporting the replacement of cold and hot spray modules, which facilitates multi-condition comparative tests on the same model body, improving experimental efficiency and comparability.

[0017] The experimental device provided by this invention has a compact structure and a well-decoupled force measurement system. It can be widely used for aerodynamic measurement under conditions with large differences between high and low loads, and provides high-precision experimental data support for the design of aircraft control systems under conditions of main engine reverse jet interference. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the experimental device in an embodiment of the present invention.

[0020] Explanation of reference numerals in the attached drawings: 1-Main model; 2-Support rod; 3-Jet generator; 301-Nozzle; 302-Jet reservoir; 4-First force balance; 5-Second force balance; 6-Air supply line; 7-Pressure sensor. Detailed Implementation

[0021] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] Example A test device for measuring the force of reverse jet interference from an aircraft main engine, such as Figure 1 As shown, the system includes the main model 1, support rods 2, jet generator 3, force balance system, air supply system, and data acquisition system. Specific details are as follows: The main body of the model 1 has an internal cavity for accommodating equipment, which is used to install support rods 2, jet generators 3, first force balances 4, and second force balances 5.

[0025] Support rod 2 is connected to the model body 1 and is used to install the model body 1 in the wind tunnel test section. One end of support rod 2 is fixed in the middle position inside the model body 1, and the other end, away from the first force balance 4, extends out of the model body 1 and is installed in the wind tunnel test section during the test.

[0026] The jet generator 3 is detachably installed at the front end inside the main body 1 of the model. It includes a cold jet generator and a hot jet generator. The cold jet generator or the hot jet generator can be selected according to the simulation conditions.

[0027] The cold jet generator uses room temperature high-pressure air as the jet medium and simulates different thrust conditions by adjusting the air supply pressure; the hot jet generator is a gas generator used to simulate the actual engine start-up state.

[0028] The nozzle 301 of the jet generator 3 is opposite to the direction of the incoming flow, forming a reverse jet. The jet generator 3 has a jet reservoir 302 inside to stabilize the jet pressure. A pressure sensor 7 is installed on the front end of the jet generator 3 to measure the pressure in the jet reservoir 302.

[0029] The jet generator 3 and the first force balance 4 are connected by a cylindrical fit and a pin. When installing the jet generator 3 and the first force balance 4, a gap must be maintained between them and the model body 1 to ensure that the jet generator 3 does not contact the model body 1 when it is turned on.

[0030] The jet generator 3 adopts a replaceable design, supporting the replacement of cold spray and hot spray modules, which facilitates multi-condition comparative tests on the same model, improving test efficiency and test comparability.

[0031] The force balance system includes a first force balance 4 and a second force balance 5. One end of the first force balance 4 is fixedly connected to the support rod 2, and the other end is connected to the jet generator 3, used to measure the thrust generated by the main engine. The second force balance 5 is fixedly installed inside the model body 1 and fitted onto the support rod 2, used to measure the aerodynamic interference force experienced by the model body 1. During installation, the front end of the second force balance 5 is fixedly connected to the interior of the model body 1, and the rear end is fixedly connected to the interior of the support rod 2. The first force balance 4 and the second force balance 5 are spatially decoupled to avoid load transfer and measurement crosstalk, ensuring accuracy within their respective measurement ranges.

[0032] This invention employs a dual force balance system to independently measure the thrust of the main engine and the aerodynamic interference force on the model body, solving the problem of insufficient measurement accuracy of a single balance due to large differences in load, and significantly improving the measurement resolution of minute interference forces.

[0033] An air supply system, used to supply air to the jet generator 3, includes an air supply pipe 6, which passes through the support rod 2 and the first force balance 4 and is connected to the jet generator 3, for supplying air to the jet generator 3. The air supply pipe 6 is threadedly connected to the jet generator 3.

[0034] When replacing the cold jet generator with the hot jet generator, simply remove the pin, rotate the cold jet generator to separate it from the air supply line 6, remove it, then install the hot jet generator, tighten it to the air supply line 6, and finally connect it to the first force balance 4 with the pin.

[0035] The data acquisition system simultaneously acquires the output signals of the first force balance 4 and the second force balance 5, enabling independent measurement of the main engine thrust and aerodynamic interference force.

[0036] The specific steps of the test method for measuring the force of reverse jet interference of an aircraft main engine using the above-mentioned test apparatus are as follows: S1. Select a cold jet generator or a hot jet generator according to the test requirements and install it inside the front end of the model body 1; S2. Install the model body 1 on the wind tunnel test section via the support rod 2, and connect the air supply pipeline 6 and the data acquisition cable; S3. Calibrate the first force balance 4 and the second force balance 5 to determine their measurement accuracy; S4. Start the wind tunnel, adjust the incoming Mach number to the target operating condition, and start the jet flow after the flow field stabilizes. S5. The data acquisition system synchronously acquires the output signals of the first force balance 4 and the second force balance 5 to obtain the thrust data of the main engine and the aerodynamic disturbance force data of the model body 1; S6. Change the jet pressure ratio and model angle of attack to conduct multi-condition combination tests; S7. Analyze the test data and evaluate the impact of the reverse jet on the overall aerodynamic performance of the aircraft.

[0037] Under the same aerodynamic shape and incoming flow conditions, comparative tests were conducted on cold spray and hot spray conditions to study the influence of hot spray flow effect on aerodynamic interference characteristics.

[0038] This invention provides an experimental model device and method for measuring the interference of reverse jet flow from a main engine. It aims to address the problem that traditional single-balance systems struggle to balance measurement range and accuracy when the main engine thrust is too large and the aerodynamic interference force is too small (difference of nearly one order of magnitude). The experimental device employs a dual-balance system: the first balance measures the main engine thrust, and the second balance measures the aerodynamic force acting on the model body, enabling independent and accurate measurement of high and low loads. A replaceable main engine jet generator is installed at the front of the model body, supporting rapid replacement of the cold jet module and the hot jet module to respectively realize room-temperature high-pressure air jet and high-temperature gas jet. The air supply system supplies air through internal air supply pipelines, and the data acquisition system simultaneously acquires the two force measurement signals. This invention is applicable to the study of the interference characteristics of reverse jet flow from the main engine of reusable rockets and landers, and has significant engineering application value.

[0039] The experimental device for measuring the force of the reverse jet interference of the main engine of an aircraft provided by the present invention has a compact structure and a well-decoupled force measurement system. It can be widely used for aerodynamic measurement under conditions with large differences between high and low loads, and provides high-precision experimental data support for the design of the control system of an aircraft under the interference of the main engine reverse jet.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A test device for measuring the force of reverse jet interference from an aircraft main engine, characterized in that, include: The main body of the model (1) has an internal cavity for accommodating equipment; Support rod (2), connected to the model body (1), used to install the model body (1) in the wind tunnel test section; The jet generator (3) is detachably installed at one end inside the model body (1). The jet generator (3) includes a cold jet generator and a hot jet generator. The cold jet generator or the hot jet generator is selected to be connected to the model body (1) according to the simulation conditions. The force balance system includes a first force balance (4) and a second force balance (5) installed inside the model body (1). One end of the first force balance (4) is connected to the jet generator (3), and the other end is connected to the support rod (2) for measuring the thrust generated by the main engine. The second force balance (5) is sleeved on the outside of the support rod (2) for measuring the aerodynamic interference force on the model body (1). An air supply system for supplying air to the jet generator (3); The data acquisition system is used to synchronously acquire the output signals of the first force balance (4) and the second force balance (5) to realize independent measurement of the main engine thrust and aerodynamic interference force.

2. The experimental apparatus according to claim 1, characterized in that, The gas supply system includes a gas supply pipeline (6), which passes through the support rod (2), the first force balance (4), and is connected to the jet generator (3). The gas supply pipeline (6) and the jet generator (3) are connected by threads.

3. The experimental apparatus according to claim 1, characterized in that, The jet generator (3) and the first force balance (4) are fitted with cylindrical surfaces and connected by pins; when the jet generator (3) and the first force balance (4) are installed, a gap must be maintained between them and the model body (1) to ensure that the jet generator (3) does not contact the model body (1) when it is turned on.

4. The experimental apparatus according to claim 1, characterized in that, The cold jet generator uses room temperature high-pressure air as the jet medium and simulates different thrust conditions by adjusting the air supply pressure.

5. The experimental apparatus according to claim 1, characterized in that, The thermal jet generator is a gas generator used to simulate the start-up state of a real engine.

6. The experimental apparatus according to claim 1, characterized in that, The first force balance (4) and the second force balance (5) are spatially decoupled to avoid load transfer and measurement crosstalk, and to ensure the accuracy within their respective measurement ranges.

7. The experimental apparatus according to claim 1, characterized in that, The jet generator (3) has a nozzle (301) at the front end and a jet storage chamber (302) inside for stabilizing the jet pressure; the front end of the jet generator (3) is provided with a pressure sensor (7) for measuring the pressure of the jet storage chamber (302); the nozzle (301) is opposite to the incoming flow direction to form a reverse jet.

8. The test apparatus according to claim 1, characterized in that, The end of the support rod (2) that is away from the first force balance (4) extends out of the model body (1).

9. A test method for measuring the force caused by the reverse jet interference of an aircraft main engine, characterized in that, Based on the test apparatus according to any one of claims 1-8, the steps include: S1. Select a cold jet generator or a hot jet generator according to the test requirements and install it inside the front end of the model body (1); S2. Install the model body (1) on the wind tunnel test section through the support rod (2), and connect the air supply pipeline (6) and the data acquisition cable; S3. Calibrate the first force balance (4) and the second force balance (5) to determine their measurement accuracy; S4. Start the wind tunnel, adjust the incoming Mach number to the target operating condition, and turn on the jet generator after the flow field stabilizes; S5. The data acquisition system synchronously acquires the output signals of the first force balance (4) and the second force balance (5) to obtain the thrust data of the main engine and the aerodynamic disturbance force data of the model body (1); S6. Change the jet pressure ratio and the angle of attack of the main body of the model (1) to carry out multi-condition combination test; S7. Analyze the test data and evaluate the impact of the reverse jet on the overall aerodynamic performance of the aircraft.

10. The test method according to claim 9, characterized in that, Under the same aerodynamic shape and incoming flow conditions, comparative tests were conducted on cold spray and hot spray conditions to study the influence of hot spray flow effect on aerodynamic interference characteristics.

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