Free incoming flow wind tunnel pressure and heat measuring system and test method

Abstract

The invention discloses a free incoming flow wind tunnel pressure and heat measuring system and a test method, and belongs to the technical field of wind tunnel pressure and heat measuring tests. The problem that in the prior art, pressure data and heat flow data are difficult to collect is solved. According to the technical key points, a blade bending mechanism is arranged in a wind tunnel, a middle support is installed at the bottom of the blade bending mechanism and connected with a test model through a supporting rod, a hatch cover is arranged above the blade bending mechanism, a local control cabinet and a hydraulic cylinder are fixedly installed on the hatch cover, and the hydraulic cylinder drives the blade bending mechanism to move up and down. It can be guaranteed that the model reaches the corresponding position 0.2 s after wind starting of a wind tunnel is stabilized, heat flow data are collected, and surface pressure distribution of the model is collected after the model is stabilized for 8 s in a flow field; after data acquisition is completed, the model can be recovered within 0.2 s, and it is guaranteed that the model is not damaged by the impact load; collection of surface pressure data and heat flow data of the model can be completed under the same train number, and time consistency of the two kinds of data is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of wind tunnel pressure measurement and heat measurement tests, and in particular to a free-flow wind tunnel pressure measurement and heat measurement system and a test method. Background Art

[0002] When an aircraft flies at hypersonic speed in the atmosphere, it interacts with the surrounding air to form shock waves. After the surrounding air is strongly compressed by the shock waves, it produces intense friction with the aircraft, resulting in the formation of a high-temperature boundary layer on the aircraft surface. Part of the heat energy is transferred to the aircraft surface through the boundary layer, causing the surface structure and materials of the aircraft to bear huge aerodynamic heating loads. This is the "aerodynamic heat" phenomenon. The aerodynamic heat problem will cause great damage to the aircraft structure. When the aircraft flies at high speed, the air flow on its surface will change dramatically, especially in the high Mach number and high Reynolds number flight state, which is a more complex problem. Therefore, studying the pressure distribution and heat flow distribution of the aircraft surface flow field is of great significance to the aircraft structure design.

[0003] In the prior art, the research methods of pressure distribution and heat flux distribution on the aircraft surface are the same as those of most physical problems, including theoretical and numerical analysis, wind tunnel tests of scaled models, ground thermal tests of aircraft structures, and flight tests. Wind tunnel tests are a technical means of simulating the actual flight process state of an aircraft through the geometric similarity of the model and the similarity of thermodynamic parameters. The pressure measurement and heat measurement wind tunnel tests can more intuitively observe and study the pressure distribution and heat flux distribution on the model surface, and further study the model design issues. However, the collected pressure data is steady-state data, and the collection of heat flux data must meet the one-dimensional semi-infinite body heat conduction theory, which is transient data. It is difficult to collect both types of data at the same time, and it is highly dangerous under high Mach number and high Reynolds number inflow conditions.

[0004] Therefore, it is urgent to propose a free-flow wind tunnel pressure and heat measurement system and test method to solve the problem of difficulty in collecting pressure data and heat flow data in the existing technology. Summary of the invention

[0005] In view of the above facts, in order to solve the problem of difficulty in collecting pressure data and heat flow data in the prior art, the present invention further designs a free flow wind tunnel pressure and heat measurement system and test method.

[0006] To achieve the above object, the present invention adopts the following technical solution: Solution 1: A free-flow wind tunnel pressure and heat measurement system, including a test model, a support rod, a middle support, a scimitar mechanism, a hatch, a local control cabinet, a hydraulic cylinder, a thermal flow data acquisition system, a pressure data acquisition system, and a wind tunnel data acquisition system; The scimitar mechanism is arranged in the wind tunnel, a middle bracket is installed at the bottom of the scimitar mechanism, and the middle bracket is connected to the test model through a support rod; A hatch cover is arranged above the scimitar mechanism, and a local control cabinet and a hydraulic cylinder are fixedly installed on the hatch cover, and the hydraulic cylinder drives the scimitar mechanism to move up and down; A pressure sensor is provided on the upper surface of the test model, and the pressure sensor is connected to the pressure data acquisition system through a scanning valve; A heat flow sensor is provided on the lower surface of the test model, and the heat flow sensor is connected to the heat flow data acquisition system through a data adapter box; The wind tunnel data acquisition system is connected to the local control cabinet, and the wind tunnel data acquisition system is wirelessly connected to the thermal flow data acquisition system and the pressure data acquisition system.

[0007] Furthermore: the model of the scanning valve is PSI64HD.

[0008] Furthermore: an optical observation window is provided on the wind tunnel, and the optical observation window is located at the rear side of the scimitar mechanism.

[0009] Furthermore: the stroke of the test model is 650 mm. Before the test, the test model is located above the nozzle. During the test, the hydraulic cylinder drives the scimitar mechanism to descend, thereby driving the test model downward to a position facing the nozzle outlet.

[0010] Solution 2: A free-flow wind tunnel pressure and heat measurement test method, the operation process is as follows: Step 1: After all the test systems are in place, the wind tunnel starts to blow; Step 2: After the flow field is stable, the thermal flow data acquisition system starts to collect thermal flow data; Step 3: The scimitar mechanism drives the test model to descend to the test position within 0.2s; Step 4: The heat flow data acquisition system receives the heat flow sensor signal and obtains the real-time data of the heat flow on the surface of the test model. After the test model is completely in the uniform flow field area, the heat flow data acquisition system collects heat flow data for a total of 3 seconds; Step 5: After the test model is stable for 5 seconds, the pressure data acquisition system receives the surface pressure signal of the test model and obtains the surface pressure data; Step 6: After the surface pressure data is collected, the hydraulic cylinder controls the scimitar mechanism to return the test model to its initial position; Step 7: Stop the wind tunnel, end the test, and save the test data.

[0011] The beneficial effects of the present invention are: 1. When the present invention is used to perform pressure and heat measurement tests in a free-flow wind tunnel, it can ensure that the model reaches the corresponding position 0.2 seconds after the wind in the wind tunnel becomes stable, collect heat flow data, and collect the surface pressure distribution of the model after it stabilizes in the flow field for 8 seconds. After the data collection is completed, the model can be retracted within 0.2 seconds to ensure that the model is not damaged by the impact load.

[0012] 2. The present invention collects pressure data through a model surface pressure sensor and collects heat flow data through a model surface heat flow sensor, and can complete the collection of model surface pressure data and heat flow data in the same train, ensuring the time consistency of the two types of data. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram showing the model being completely within the wind tunnel flow field; Figure 3 Provide a roadmap for pressure data transmission; Figure 4 Roadmap for heat flow data transmission.

[0014] In the figure: 1. Test model, 2. Support rod, 3. Middle bracket, 4. Scimitar mechanism, 5. Hatch cover, 6. Local control cabinet, 7. Hydraulic cylinder, 8. Optical observation window, 9. Thermal flow data acquisition system, 10. Pressure data acquisition system, 11. Wind tunnel data acquisition system, 17. Nozzle outlet. DETAILED DESCRIPTION

[0015] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0016] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0017] In the present application, the directions or positional relationships indicated by the terms "upper", "lower", "inner", "middle", "outer", "front", "back", etc. are based on the directions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific direction, or to be constructed and operated in a specific direction.

[0018] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0019] In addition, the terms "disposed", "connected", and "fixed" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0020] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0021] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0022] Embodiment 1: A free-flow wind tunnel pressure and heat measurement system, comprising a test model 1, a support rod 2, a middle support 3, a scimitar mechanism 4, a hatch 5, a local control cabinet 6, a hydraulic cylinder 7, a thermal flow data acquisition system 9, a pressure data acquisition system 10, and a wind tunnel data acquisition system 11; The scimitar mechanism 4 is arranged in the wind tunnel, and a middle bracket 3 is installed at the bottom of the scimitar mechanism 4, and the middle bracket 3 is connected to the test model 1 through a support rod 2; A hatch cover 5 is provided above the scimitar mechanism 4, on which a local control cabinet 6 and a hydraulic cylinder 7 are fixedly installed, and an output end of the hydraulic cylinder 7 passes through the hatch cover 5 and is connected to the upper end of the scimitar mechanism 4, and the hydraulic cylinder 7 drives the scimitar mechanism 4 to move up and down; The upper surface of the test model 1 is provided with a pressure sensor, which is connected to the pressure data acquisition system 10 through a scanning valve; A heat flow sensor is provided on the lower surface of the test model 1, and the heat flow sensor is connected to the heat flow data acquisition system 9 through a data adapter box; The wind tunnel data acquisition system 11 is connected to the local control cabinet 6 , and the wind tunnel data acquisition system 11 is wirelessly connected to the thermal flow data acquisition system 9 and the pressure data acquisition system 10 .

[0023] More specifically: the pressure sensor is connected to the pressure data acquisition system 10 through a scanning valve, converts the pressure data into an electrical signal, and converts the electrical signal into a digital signal through the scanning valve and PSI9000, and transmits it to the pressure data acquisition system 10 for collection, aggregation and analysis; The model of the scanning valve is PSI64HD; The PSI9000 is a miniature electronic pressure scanner used in conjunction with a scanning valve.

[0024] More specifically: 8 of the thermal flow sensors form a group, and a group of thermal flow sensors is connected to a data adapter box through an extension line. The data adapter box transmits the electrical signal to the thermal flow data acquisition system 9 through the data acquisition line. The thermal flow data acquisition system 9 converts the electrical signal into a digital signal and transmits it to the wind tunnel data acquisition system 11.

[0025] More specifically: the wind tunnel is provided with an optical observation window 8, which is located at the rear side of the scimitar mechanism 4, and a Schlieren system is arranged outside the optical observation window 8. The camera and reflector used in the Schlieren system are mounted at the designed position to ensure a certain angle, so that the flow field and the state of the model itself can be obtained in real time.

[0026] More specifically: the stroke of the test model 1 is 650 mm. In order to prevent the thermal flux sensor from being affected during the establishment of the flow field, the test model 1 is located above the nozzle before the test. During the test, the hydraulic cylinder 7 drives the scimitar mechanism 4 to descend, thereby driving the test model 1 downward to a position facing the nozzle outlet 17.

[0027] More specifically: the test model 1 is made of 30CrMnSiA stainless steel, which can effectively prevent the influence of model heat transfer on heat flow data collection.

[0028] More specifically: the time to complete one lift is controlled within 0.2s.

[0029] Embodiment 2: A free flow wind tunnel pressure and heat measurement test method of this embodiment, the operation process is as follows: Step 1: After all the test systems are in place, the wind tunnel starts to blow; Step 2: After the flow field is stable, the heat flow data acquisition system 9 starts to collect heat flow data; Step 3: The scimitar mechanism 4 drives the test model 1 to descend to the test position within 0.2s; Step 4: The heat flow data acquisition system 9 receives the heat flow sensor signal and obtains the real-time data of the heat flow on the surface of the test model 1. After the test model 1 is completely in the uniform flow field area, the heat flow data acquisition system 9 collects the heat flow data for a total of 3 seconds; Step 5: After the test model 1 is stable for 5 seconds, the pressure data acquisition system 10 receives the surface pressure signal of the test model 1 and obtains the surface pressure data; Step 6: After the surface pressure data is collected, the hydraulic cylinder 7 controls the scimitar mechanism 4 to return the test model 1 to the initial position; Step 7: Stop the wind tunnel, end the test, and save the test data.

[0030] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, the technical solutions described in the aforementioned embodiments can still be modified, or some or all of the technical features therein can be replaced by equivalents. As long as there is no structural conflict, the various features in the specific implementation methods disclosed in this application can be combined with each other in any way, and the essence of the corresponding technical solutions will not deviate from the scope of the technical solutions of the present invention.

[0031] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A free-flow wind tunnel pressure and heat measurement system, characterized in that: It includes a test model (1), a support rod (2), a middle support (3), a scimitar mechanism (4), a hatch cover (5), a local control cabinet (6), a hydraulic cylinder (7), a thermal flow data acquisition system (9), a pressure data acquisition system (10), and a wind tunnel data acquisition system (11); The scimitar mechanism (4) is arranged in a wind tunnel, a middle bracket (3) is installed at the bottom of the scimitar mechanism (4), and the middle bracket (3) is connected to the test model (1) via a support rod (2); A hatch cover (5) is arranged above the scimitar mechanism (4), a local control cabinet (6) and a hydraulic cylinder (7) are fixedly mounted on the hatch cover (5), an output end of the hydraulic cylinder (7) passes through the hatch cover (5) and is connected to the upper end of the scimitar mechanism (4), and the hydraulic cylinder (7) drives the scimitar mechanism (4) to move up and down; The upper surface of the test model (1) is provided with a pressure sensor, which is connected to a pressure data acquisition system (10) via a scanning valve; A heat flow sensor is provided on the lower surface of the test model (1), and the heat flow sensor is connected to a heat flow data acquisition system (9) via a data adapter box; The wind tunnel data acquisition system (11) is connected to the local control cabinet (6), and the wind tunnel data acquisition system (11) is wirelessly connected to the thermal flow data acquisition system (9) and the pressure data acquisition system (10).

2. A free-flow wind tunnel pressure and heat measurement system according to claim 1, characterized in that: The model of the scanning valve is PSI64HD.

3. A free-flow wind tunnel pressure and heat measurement system according to claim 1, characterized in that: An optical observation window (8) is provided on the wind tunnel, and the optical observation window (8) is located at the rear side of the scimitar mechanism (4).

4. A free-flow wind tunnel pressure and heat measurement system according to claim 1, characterized in that: The stroke of the test model (1) is 650 mm. Before the test, the test model (1) is located above the nozzle. During the test, the hydraulic cylinder (7) drives the scimitar mechanism (4) to descend, thereby driving the test model (1) downward to a position directly facing the nozzle outlet (17).

5. A free-flow wind tunnel pressure and heat measurement test method, characterized in that: The operation process is: Step 1: After all the test systems are in place, the wind tunnel starts to blow; Step 2: After the flow field is stabilized, the heat flow data acquisition system (9) starts to collect heat flow data; Step 3: The scimitar mechanism (4) drives the test model (1) to descend to the test position within 0.2 seconds; Step 4: The heat flow data acquisition system (9) receives the heat flow sensor signal and obtains real-time data of the heat flow on the surface of the test model (1). After the test model (1) is completely in the uniform flow field area, the heat flow data acquisition system (9) collects heat flow data for a total of 3 seconds; Step 5: After the test model (1) is stable for 5 seconds, the pressure data acquisition system (10) receives the surface pressure signal of the test model (1) and obtains the surface pressure data; Step 6: After the surface pressure data is collected, the hydraulic cylinder (7) controls the scimitar mechanism (4) to return the test model (1) to the initial position; Step 7: Stop the wind tunnel, end the test, and save the test data.

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