Model for high-Mach-number high-enthalpy transition test

Abstract

The utility model relates to a model for a high-Mach-number and high-enthalpy transition test, which has the typical characteristics of large size, axial symmetry, sharp front edge and skirt cone tail part, and can be divided into three parts, namely a sharp front edge, a straight cone middle part and a skirt cone tail part. According to the utility model, the problem that a conventional model is difficult to generate a transition phenomenon under a high-Mach-number and high-enthalpy flow condition is solved, the transition phenomenon can be promoted to a great extent, and a foundation is laid for further carrying out transition test research under the high-Mach-number and high-enthalpy flow condition.

Description

Technical Field

[0001] The utility model relates to a model for high Mach number and high enthalpy transition tests, belonging to the field of test measurement. Background Art

[0002] Hypersonic boundary layer transition is a hot research topic, and the high-temperature gas effect has an important impact on the boundary layer transition at high Mach numbers. In wind tunnel tests, due to the pressure-bearing capacity limitation of wind tunnel equipment, the incoming unit Reynolds number of the high Mach number and high enthalpy flow field is relatively low, and it is difficult for the boundary layer transition phenomenon to occur on the surface of the wind tunnel test model, thus it is difficult to obtain the boundary layer transition data under the conditions of high Mach number and high enthalpy flow field. Content of the Utility Model

[0003] The technical problem solved by this application is: overcoming the deficiencies of the prior art, providing a model for high Mach number and high enthalpy transition tests, which can achieve boundary layer transition under the conditions of high Mach number and high enthalpy flow field, and solving the test verification problem in the research on the influence of high-temperature gas effect on boundary layer transition.

[0004] The technical solution provided by this application is as follows:

[0005] A model for high Mach number and high enthalpy transition tests, the model is a rotating body, the model includes a straight cone section and a skirt cone tail, the skirt cone tail is connected to the large-diameter end of the straight cone section, the diameter of the large-diameter end of the straight cone section is smaller than the diameter of the end of the skirt cone tail far from the straight cone section, the generatrix of the skirt cone tail is an arc, and the circumferential surface of the skirt cone tail is tangent to the straight cone section for smooth transition.

[0006] The sum of the half-cone angle θ1 of the straight cone section and the maximum central angle θ2 of the arc part of the skirt cone tail is less than 90°.

[0007] The head radius of the straight cone section is less than 0.05 mm.

[0008] The straight cone section includes a sharp leading edge and a straight cone middle part, and the sharp leading edge and the straight cone middle part are detachably connected.

[0009] The sharp leading edge part is made of high-strength and high-stiffness materials.

[0010] The total length of the straight cone section = (1 / 2 to 3 / 4) × the total length L of the model.

[0011] The length of the sharp leading edge is (1 / 12 to 1 / 4) × the total length L of the model, and the length of the straight cone middle part is (1 / 4 to 2 / 3) × the total length L of the model.

[0012] The total length L of the model is the maximum length that enables the entire model to be located within the uniform area of the wind tunnel flow field.

[0013] The bottom radius R1 of the model is determined according to the blockage requirement for the startup of the wind tunnel flow field; based on the total length L and the bottom diameter R1, the minimum conical shock wave angle of the straight conical section where the head shock wave does not hit the model is calculated, and the half-cone angle of the straight conical section = 1 / 2 × the minimum conical shock wave angle.

[0014] The model has the characteristics of large size, axisymmetry, sharp leading edge, and skirt cone tail.

[0015] The large-size characteristic refers to the length of the test model, which is the length of the model along the central axis and is the maximum length that ensures the entire model is located within the uniform area of the wind tunnel flow field.

[0016] The maximum length that ensures the entire model is located within the uniform area of the wind tunnel flow field is the length of the model along the central axis on the premise that the tail of the model does not exceed the uniform area of the flow field.

[0017] The axisymmetry characteristic means that the test model has a central axis of symmetry and the model is a solid of revolution.

[0018] The sharp leading-edge characteristic means that the designed value of the head radius of the model is zero, and the leading-edge radius of the actually processed model is less than 0.05 mm. The sharp leading-edge part of the model is made of high-strength and high-stiffness materials.

[0019] The skirt cone tail characteristic means that the generatrix of the model tail is an arc, the arc is tangent to the middle straight cone, and the sum of the maximum central angle of the arc part and the half-cone angle of the middle section cone is less than 90°.

[0020] In summary, the present application includes at least the following beneficial technical effects:

[0021] (1) Comprehensively utilize the scale effect (model length), bluntness effect (sharp leading edge), and adverse pressure gradient (skirt cone tail) of the model to promote the occurrence of boundary layer transition under high Mach number and high enthalpy flow fields;

[0022] (2) The model has a simple structure, is convenient to process, has clear flow phenomena, and is convenient for carrying out research on flow mechanisms. Description of the Drawings

[0023] Figure 1 It is an isometric view of the model;

[0024] Figure 2 It is a cross-sectional dimension view of the model.

[0025] Explanation of the reference numerals in the drawings: 1. Straight conical section; 11. Sharp leading edge; 12. Middle part of the straight cone; 2. Skirt cone tail. Detailed Embodiments

[0026] To make the objectives, technical solutions, and advantages of the present utility model clearer, the following will further describe in detail the disclosed embodiments of the present utility model with reference to the drawings.

[0027] An embodiment of the present utility model provides a model for high Mach number and high enthalpy transition tests, which can achieve boundary layer transition under high Mach number and high enthalpy flow field conditions, and solves the problem of experimental verification in the study of the influence of high temperature gas effects on boundary layer transition.

[0028] A model for high Mach number and high enthalpy transition tests provided by this embodiment, such as Figure 1 shown, the model has a central axis of symmetry and is a body of revolution; the model includes a straight cone section 1 and a skirt cone tail 2 connected in sequence.

[0029] The straight cone section 1 includes a sharp leading edge 11 and a middle part of the straight cone 12. The sharp leading edge 11 is easily damaged, and the sharp leading edge 11 and the middle part of the straight cone 12 are detachably connected, which is convenient for replacing the sharp leading edge 11. The designed value of the head radius of the model is zero, and the head radius of the sharp leading edge 11 of the actually processed model is less than 0.05 mm. The sharp leading edge 11 part of the model is made of high-strength and high-rigidity materials.

[0030] The skirt cone tail 2 is connected to the large diameter end of the straight cone section 1. The diameter of the large diameter end of the straight cone section 1 is less than the diameter of the end of the skirt cone tail 2 far from the straight cone section 1. The generatrix of the skirt cone tail 2 is an arc, the arc is tangent to the middle part of the straight cone 12, and the sum of the maximum central angle θ2 of the arc part and the half cone angle θ1 of the middle section cone is less than 90°.

[0031] The total length L of the model is the maximum length that enables the entire model to be located within the uniform area of the wind tunnel flow field. The total length of the model is the length of the model along the central axis.

[0032] As Figure 2 shown, in the model design, first, according to the uniform area of the wind tunnel flow field, ensure that the model is within the uniform area range to determine the total length L of the model; determine the bottom radius R1 of the model according to the blockage degree requirement for the start-up of the wind tunnel flow field. At the same time. Then, calculate the minimum cone shock angle at which the head shock wave will not hit the model based on the total length L and the bottom diameter R1 of the model, and then calculate the corresponding half cone angle of the cone. Then determine the total length of the straight cone section 1, and it is recommended to take (sharp leading edge and middle part of the straight cone ), to ensure that the bottom diameter of the middle part of the straight cone 12 is less than the bottom diameter R1 of the model. The skirt cone tail 2 adopts an arc. Under the requirements of smooth transition of the arc tangent to the middle part of the straight cone 12 and the diameter being consistent with the previously determined diameter at the tail, the final arc radius R2 is also determined accordingly.

[0033] Embodiment

[0034] Figure 2For a specific embodiment, the model is divided into three parts: a sharp leading edge 11, a straight conical middle part 12, and a skirt conical tail part 2. The total length of the model L = 1500 mm, and the radius of the tail part R1 = 350 mm. The predicted minimum allowable shock wave angle is 13.134°, and the semi-cone angle of the cone under the flow field conditions of Mach number 10 is selected as θ1 = 11°. The sharp leading edge 11 is 250 mm long and the straight conical middle part 12 is 750 mm long, with a total length of 1000 mm. The skirt conical tail part 2 is 500 mm long. According to the geometric relationship, the arc radius R2 of the cross-section of the skirt conical tail part 2 is determined to be 2390 mm, and the central angle of the arc θ2 = 12°. The overall model is machined from a 30CrMnSiA material with high strength and high stiffness. After machining, the radius of the leading edge of the model is less than 0.05 mm. This model has been applied to the experimental study of boundary layer transition in a high Mach number and high enthalpy flow field.

[0035] The model designed in the present invention adopts this axisymmetric shape to avoid the disadvantage that the edges of the two-dimensional shape model will interfere with the measurement of the effective area on the model. The model designed in the present invention has the characteristic of large size, which will make the flow direction size of the model larger, and will greatly increase the development distance of the boundary layer on the model surface, making it easier to generate the boundary layer transition phenomenon on the model surface. In the present invention, the model design adopts a theoretical sharp leading edge (zero bluntness). According to the existing numerical and experimental results, it shows that reducing the bluntness of the leading edge of the conical model will promote the boundary layer transition, and can greatly promote the boundary layer transition on the model surface. The skirt conical shape adopted in the tail design of the model in the present invention, compared with the straight conical shape of the cone, will cause an adverse pressure gradient in the flow. According to the existing numerical and experimental studies, this adverse pressure gradient will also promote the transition.

[0036] The content not described in detail in the specification of this application belongs to the well-known technology of those skilled in the art.

[0037] The above has described this application in detail in combination with specific embodiments and exemplary examples. However, these descriptions should not be construed as limitations on this application. Those skilled in the art understand that without departing from the spirit and scope of this application, various equivalent substitutions, modifications, or improvements can be made to the technical solutions and their implementation manners of this application, and these all fall within the scope of this application. The protection scope of this application is subject to the appended claims.

Claims

1. A model for high Mach number and high enthalpy transition experiments, characterized in that: The model is a solid of revolution, which includes a straight cone section (1) and a skirt cone tail (2). The skirt cone tail (2) is connected to the large-diameter end of the straight cone section (1). The diameter of the large-diameter end of the straight cone section (1) is smaller than the diameter of the end of the skirt cone tail (2) far from the straight cone section (1). The generatrix of the skirt cone tail (2) is an arc, and the circumferential surface of the skirt cone tail (2) is tangent to the straight cone section (1) for a smooth transition.

2. The model for high Mach number and high enthalpy transition test according to claim 1, characterized in that: The sum of the half-cone angle θ1 of the straight cone section (1) and the maximum central angle θ2 of the arc part of the skirt cone tail (2) is less than 90°.

3. A model for high Mach number and high enthalpy transition experiments according to claim 1, characterized in that: The head radius of the straight cone section (1) is less than 0.05 mm.

4. A model for high Mach number and high enthalpy transition experiments according to claim 1, characterized in that: The straight cone section (1) includes a sharp leading edge (11) and a straight cone middle part (12), and they are detachably connected between the sharp leading edge (11) and the straight cone middle part (12).

5. A model for high Mach number and high enthalpy transition experiments according to claim 4, characterized in that: The sharp leading edge (11) is made of a material with high strength and high stiffness.

6. A model for high Mach number and high enthalpy transition experiments according to claim 1, characterized in that: The total length of the straight cone section (1) = (1 / 2 to 3 / 4) × the total length L of the model.

7. A model for high Mach number and high enthalpy transition experiments according to claim 4, characterized in that: The length of the sharp leading edge (11) is (1 / 12 to 1 / 4) × the total length L of the model, and the length of the straight cone middle part (12) is (1 / 4 to 2 / 3) × the total length L of the model.

8. A model for high Mach number and high enthalpy transition experiments according to claim 6 or 7, characterized in that: The total length L of the model is the maximum length that enables the entire model to be located within the uniform region of the wind tunnel flow field.

9. A model for high Mach number and high enthalpy transition experiments according to claim 8, characterized in that: The bottom radius R1 of the model is determined according to the blockage degree requirement for the start of the wind tunnel flow field; the minimum conical shock wave angle of the straight cone section (1) where the head shock wave will not hit the model is calculated based on the total length L and the bottom radius R1, and the half-cone angle of the straight cone section (1) = 1 / 2 × the minimum conical shock wave angle.

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