Device and method for spreading tracer particles near the wall of hypersonic boundary layer

Abstract

The present invention discloses a device and method for spreading tracer particles near the wall of a hypersonic boundary layer. The device comprises: a pressure control device, a pressure pipeline, a one-way valve, a tracer particle generator and a model tank; the pressure control device is connected to the pressure pipeline and is used to generate a control pressure within a specific range, and the pressure pipeline is used to transmit the control pressure to the tracer particle generator; the one-way valve is arranged in the pressure pipeline and is used to prevent the reverse transmission of tracer particles; the tracer particle generator is connected to the model tank and is used to generate a corresponding internal pressure based on the control pressure and generate uniformly dispersed tracer particles under the internal pressure; the model tank is connected to the tracer particle generator and transmits the tracer particles to the near wall of the model boundary layer. The present invention realizes precise pressure regulation through the pressure control device, ensures that the speed at which the tracer particles enter the boundary layer is very low, and realizes the spreading of tracer particles near the wall of the boundary layer.

Description

Technical Field

[0001] The present invention relates to the technical field of fluid mechanics experiments, and in particular to a device and method for spreading tracer particles near the wall of a hypersonic boundary layer. Background Art

[0002] In the full-field flow field structure measurement, the mainstream velocity field measurement accuracy has been verified by many models, but the accurate characterization of the flow field velocity inside the boundary layer, especially near the wall, has always been a difficult point in experimental measurement.

[0003] In the low-speed and sub-transonic range, it is not difficult for tracer particles to enter the boundary layer because the shear on the model surface is weak and the boundary layer is relatively thick. However, in the supersonic and hypersonic range, when using particle flow testing methods to conduct experiments, it is difficult for tracer particles to enter the boundary layer due to interference from complex factors such as sonic lines, shock waves, adverse pressure gradients and separation zones. The reduction of tracer particles in the near-wall area will lead to large errors in the cross-correlation calculation of the velocity field distribution, and it may even be impossible to conduct experimental measurements of the flow field inside the boundary layer.

[0004] At present, there is no very effective experimental method for measuring boundary layer velocity in the hypersonic field. It is planned to realize the refined flow field structure measurement of the hypersonic boundary layer / near-wall region through the development of a near-wall tracer particle seeding device. Summary of the invention

[0005] The purpose of the present invention is to provide a device and method for scattering tracer particles near the wall of a hypersonic boundary layer, aiming to solve the problem of measuring the velocity field in the near-wall region of a supersonic boundary layer.

[0006] The present invention provides a hypersonic boundary layer near-wall tracer particle sowing device, comprising: a pressure control device, a pressure pipeline, a one-way valve, a tracer particle generator and a model tank;

[0007] The pressure control device is connected to the pressure pipeline, and is used for generating a control pressure within a specific range, and transmitting the control pressure to the tracer particle generator through the pressure pipeline;

[0008] A pressure pipeline, both ends of which are respectively connected to the pressure control device and the tracer particle generator, and is used to transmit the control pressure generated by the pressure control device to the tracer particle generator;

[0009] A one-way valve is provided in the pressure pipeline to prevent the reverse transmission of the tracer particles generated by the tracer particle generator;

[0010] a tracer particle generator connected to the model tank, used to generate a corresponding internal pressure based on the control pressure, and to generate uniformly dispersed tracer particles under the internal pressure;

[0011] The model slot is connected to the tracer particle generator and is used to transmit the tracer particles generated by the tracer particle generator to the near wall surface of the model boundary layer.

[0012] The present invention provides a method for spreading tracer particles near the wall of a hypersonic boundary layer, comprising:

[0013] By placing tracer particles inside the tracer particle generator, evenly dispersed tracer particles are generated;

[0014] A control pressure within a specific range is generated by a pressure control device, and the control pressure is transmitted to a tracer particle generator through a pressure pipeline;

[0015] The tracer particle generator generates a corresponding internal pressure based on the control pressure, and generates uniformly dispersed tracer particles under the internal pressure;

[0016] The uniformly dispersed tracer particles are emitted to the near wall surface of the model boundary layer through the model slot connected to the tracer particle generator.

[0017] By adopting the embodiment of the present invention, a control pressure within a specific range is generated by a pressure control device according to the pressure size of the boundary layer, and the pressure in the tracer particle generator is adjusted. Due to the precise pressure adjustment, the speed at which the missing particles enter the boundary layer is very low, and the impact on the boundary layer is very small and will be eliminated quickly without interfering with the mainstream flow field, thereby achieving tracer particle seeding in the near-wall region of the boundary layer, compensating for the difficulty in measuring the velocity in the near-wall region of the boundary layer by the particle velocimetry method.

[0018] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 is a schematic diagram of a hypersonic boundary layer near-wall tracer particle seeding device according to an embodiment of the present invention;

[0021] Figure 2 is a flow chart of a method for spreading tracer particles near a wall in a hypersonic boundary layer according to an embodiment of the present invention;

[0022] Figure 3 It is the simulation result of the hypersonic boundary layer near-wall tracer particle spreading device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0025] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] Device Embodiment

[0027] According to an embodiment of the present invention, a hypersonic boundary layer near-wall tracer particle seeding device is provided. Figure 1 Schematic diagram of a hypersonic boundary layer near-wall tracer particle seeding device according to an embodiment of the present invention. Figure 1 As shown, the hypersonic boundary layer near-wall tracer particle spreading device according to an embodiment of the present invention specifically comprises: a pressure control device 3, a pressure pipeline 4, a one-way valve 5, a tracer particle generator 6 and a model tank 8;

[0028] The pressure control device 3 is connected to the pressure pipeline 4 and is used to generate a control pressure within a specific range and transmit the control pressure to the tracer particle generator 6 through the pressure pipeline 4. Specifically, the pressure control device 3 is used for:

[0029] Generating a control pressure within a specific range according to the pressure magnitude of the boundary layer and adjusting the pressure inside the tracer particle generator 6 through the control pressure;

[0030] Generating a control pressure with a magnitude range of P1, where P1 satisfies P0 < P1 < 2P0, and P0 is the static pressure of the boundary layer. The adjustment accuracy of generating the control pressure is greater than or equal to a specific adjustment threshold. For example, the control pressure generated by the pressure control device has a control range between 100 Pa and 10,000 Pa, and the pressure adjustment accuracy is better than 10 Pa;

[0031] The pressure pipeline 4 is connected to the pressure control device 3 and the tracer particle generator 6 at both ends and is used to transmit the control pressure generated by the pressure control device 3 into the tracer particle generator 6;

[0032] The one-way valve 5 is arranged in the pressure pipeline 4 and is used to prevent the reverse transmission of the tracer particles generated by the tracer particle generator 6;

[0033] The tracer particle generator 6 is connected to the model tank 8 and is used to generate a corresponding internal pressure based on the control pressure and generate uniformly dispersed tracer particles 7 under the internal pressure. Specifically, the tracer particle generator 6 is used for: Transmitting the tracer particles to the near-wall surface 1 of the model boundary layer at a specific low speed under the action of the pressure difference according to the control pressure. The tracer particle generator 6 generates tracer particles 7 with a diameter in the nanometer range;

[0034] The model tank 8 is connected to the tracer particle generator 6 and is used to transmit the tracer particles 7 generated by the tracer particle generator 6 to the near-wall surface 1 of the model boundary layer. The model tank 8 is arranged at a specific distance from the leading edge of the model 2. The width of the model tank 8 is less than or equal to a specific width threshold. The position of the model tank 8 should be between 10% and 20% of the distance from the leading edge of the model 2, and the width is not greater than 1 mm. For example, a square groove with a width not greater than 1 mm is opened at about 10% of the distance from the leading edge of the model 2, and the tracer particles enter the interior of the boundary layer of the model 2 from this square groove.

[0035] The following details the hypersonic boundary layer near-wall tracer particle spreading device with specific examples:

[0036] A square groove with a width not greater than 1 mm is opened at about 10% of the distance from the leading edge of the model. The tracer particles enter the interior of the model boundary layer from this square groove. The position of the square groove should be between 10% and 20% of the distance from the leading edge of the model, and the width is not greater than 1 mm;

[0037] Arrange the model, pressure control device, pressure pipeline, one-way valve, and particle generator in accordance with Figure 1 Connect in a certain way;

[0038] The pressure control range of the pressure control device is between 100 Pa and 10,000 Pa, and the pressure regulation accuracy is better than 10 Pa. The pressure of the control device is adjusted according to the pressure of the boundary layer. Assuming the static pressure of the boundary layer is P0, the size range of the pressure P1 after the pressure control device is adjusted is P0 < P1 < 2P0, so as to ensure that the velocity of the tracer particles entering the boundary layer will not be too large to prevent interference with the boundary layer.

[0039] The particle generator is used to generate uniformly dispersed tracer particles. First, place the tracer particles inside the particle generator. Under the action of the pressure control device, the tracer particles will move into the boundary layer through the model slot. The particle generator should have the ability to disperse the tracer particles so that the tracer particles will not agglomerate, ensure that they enter the boundary layer with a particle size at the nanometer level, and maintain good followability.

[0040] Due to the precise pressure regulation, the velocity of the particles entering the boundary layer is very low, the influence on the boundary layer is very small, and it will be quickly eliminated without interfering with the mainstream flow field, as Figure 3 shown by the numerical simulation calculation to verify the relevant results.

[0041] Method Embodiment

[0042] According to an embodiment of the present invention, a method for spreading tracer particles near the wall of a hypersonic boundary layer is provided. Figure 2 is a flowchart of the method for spreading tracer particles near the wall of a hypersonic boundary layer according to an embodiment of the present invention. As Figure 2 shown, the method for spreading tracer particles near the wall of a hypersonic boundary layer according to an embodiment of the present invention specifically includes:

[0043] Step S201, generate uniformly dispersed tracer particles by placing tracer particles inside the tracer particle generator;

[0044] Step S202, generate a control pressure within a specific range through the pressure control device and transmit the control pressure to the tracer particle generator through the pressure pipeline. Step S202 specifically includes: generate a control pressure within a specific range according to the pressure of the boundary layer and adjust the pressure inside the tracer particle generator through the control pressure; the control pressure is P1, and P1 satisfies P0 < P1 < 2P0, where P0 is the static pressure of the boundary layer, and the adjustment accuracy of the generated pressure is greater than or equal to a specific adjustment threshold. For example, the control pressure range generated by the pressure control device is between 100 Pa and 10,000 Pa, and the pressure regulation accuracy is better than 10 Pa;

[0045] Step S203: The tracer particle generator generates a corresponding internal pressure based on the control pressure and generates uniformly dispersed tracer particles under the internal pressure.

[0046] Step S204: The uniformly dispersed tracer particles are emitted into the near-wall region of the model boundary layer through a model slot connected to the tracer particle generator. Step S204 specifically includes: The model slot is set at a specific distance from the leading edge of the model, and the width of the model slot is less than or equal to a specific width threshold; Under the action of the pressure difference according to the control pressure, the tracer particles are transported to the near-wall region of the model boundary layer at a specific low speed. The position of the model slot should be between 10% and 20% of the distance from the leading edge of the model, and the width is not greater than 1 mm. For example, a square slot with a width not greater than 1 mm is opened at about 10% of the distance from the leading edge of the model, and the tracer particles enter the interior of the model boundary layer from this square slot.

[0047] The following details the method for spreading tracer particles in the near-wall region of the hypersonic boundary layer with specific examples:

[0048] A square slot with a width not greater than 1 mm is opened at about 10% of the distance from the leading edge of the model, and the tracer particles enter the interior of the model boundary layer from this square slot. The position of the square slot should be between 10% and 20% of the distance from the leading edge of the model, and the width is not greater than 1 mm.

[0049] Connect the model, pressure control device, pressure pipeline, one-way valve, and particle generator in the Figure 1 way.

[0050] The pressure control range of the pressure control device is between 100 Pa and 10,000 Pa, and the pressure regulation accuracy is better than 10 Pa. The pressure of the control device is adjusted according to the pressure magnitude of the boundary layer. Assuming the static pressure magnitude of the boundary layer is P0, the magnitude range P1 of the pressure adjusted by the pressure control device is P0 < P1 < 2P0 to ensure that the velocity of the tracer particles entering the boundary layer is not too large to prevent interference with the boundary layer.

[0051] The particle generator is used to generate uniformly dispersed tracer particles. First, place the tracer particles inside the particle generator. Under the action of the pressure control device, the tracer particles will move into the boundary layer through the model slot. The particle generator should have the ability to disperse the tracer particles so that the tracer particles do not agglomerate, ensuring that they enter the boundary layer with a particle size at the nanometer level and maintaining good followability.

[0052] Due to precise pressure regulation, the velocity of the particles entering the boundary layer is very low, with little impact on the boundary layer and will be quickly eliminated without interfering with the mainstream flow field, as Figure 3 shown by numerical simulation calculations to verify the relevant results.

[0053] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0054] The above description is only an embodiment of this document and is not intended to limit this document. For those skilled in the art, this document may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this document should be included in the scope of the claims of this document.

Claims

1. A hypersonic boundary layer near-wall tracer particle seeding device, characterized in that: Comprising: A pressure control device, a pressure pipeline, a one-way valve, a tracer particle generator, and a model tank; The pressure control device is connected to the pressure pipeline, and is used to generate a control pressure within a specific range, and transmit the control pressure to the tracer particle generator through the pressure pipeline; The pressure pipeline is connected to the pressure control device and the tracer particle generator at both ends respectively, and is used to transmit the control pressure generated by the pressure control device into the tracer particle generator; The one-way valve is arranged in the pressure pipeline and is used to prevent the reverse transmission of the tracer particles generated by the tracer particle generator; The tracer particle generator is connected to the model tank, and is used to generate a corresponding internal pressure based on the control pressure, and generate uniformly dispersed tracer particles under the internal pressure; The model tank is connected to the tracer particle generator, and is used to transmit the tracer particles generated by the tracer particle generator to the near-wall surface of the model boundary layer.

2. The device according to claim 1, characterized in that The pressure control device is specifically used for: generating a control pressure within a specific range according to the pressure magnitude of the boundary layer, and adjusting the pressure in the tracer particle generator through the control pressure.

3. The device according to claim 1, characterized in that The tracer particle generator is specifically used for: transmitting the tracer particles to the near-wall surface of the model boundary layer at a specific low speed under the action of a pressure difference according to the control pressure.

4. The device according to claim 1, characterized in that The pressure control device is further used for: Generating the control pressure with a pressure magnitude range of P1, where P1 satisfies P0 < P1 < 2P0, P0 is the static pressure of the boundary layer, and the adjustment accuracy of generating the control pressure is greater than or equal to a specific adjustment threshold.

5. The device according to claim 1, characterized in that The model tank is arranged at a specific distance from the leading edge of the model, and the width of the model tank is less than or equal to a specific width threshold.

6. The device according to claim 1, characterized in that The tracer particle generator is specifically used for: generating the tracer particles with a diameter in the nanometer range.

7. A method for spreading tracer particles near the wall of a hypersonic boundary layer, characterized in that: For the hypersonic boundary layer near-wall surface tracer particle spreading device according to any one of claims 1 to 6, the method includes: Generating uniformly dispersed tracer particles by placing tracer particles inside the tracer particle generator; Generating a control pressure within a specific range by the pressure control device, and transmitting the control pressure to the tracer particle generator through the pressure pipeline; The tracer particle generator generates a corresponding internal pressure based on the control pressure, and generates uniformly dispersed tracer particles under the internal pressure; Emitting the uniformly dispersed tracer particles to the near-wall surface of the model boundary layer through a model tank connected to the tracer particle generator.

8. The method according to claim 7, characterized in that The generating a control pressure within a specific range by the pressure control device specifically includes: Generating a control pressure within a specific range according to the pressure magnitude of the boundary layer, and adjusting the pressure in the tracer particle generator through the control pressure; the control pressure is P1, and P1 satisfies P0 < P1 < 2P0, where P0 is the static pressure of the boundary layer, and the adjustment accuracy of generating the pressure is greater than or equal to a specific adjustment threshold.

9. The method according to claim 7, characterized in that: The emitting the uniformly dispersed tracer particles to the near-wall surface of the model boundary layer through a model tank connected to the tracer particle generator specifically includes: The model tank is arranged at a specific distance from the leading edge of the model, and the width of the model tank is less than or equal to a specific width threshold; According to the control pressure, the tracer particles are transported to the near wall surface of the model boundary layer at a specific low speed under the action of pressure difference.

10. The method according to claim 7, characterized in that The production of uniformly dispersed tracer particles specifically includes: The uniformly dispersed tracer particles are of nanometer level.

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