High-speed transition polyhedral test model and test method for various complex effects

Abstract

The application provides a high-speed transition polyhedral test model and test method for multiple complex effects, which adopts symmetrical configuration of up and down and left and right, and comprises a main body and a variable head; the main body comprises front and rear planes, upper and lower planes and four inclined planes, the front and rear planes are vertically arranged, the front plane is provided with a cavity, the upper and lower planes are respectively arranged on the upper side and the lower side of the front and rear planes, and the two side edges of the upper and lower planes are connected through two inclined planes; the variable head comprises upper and lower surfaces, a connecting surface and two irregular side surfaces, the front edges of the upper and lower surfaces intersect at a certain angle to form a head, the head is treated with rounding, one side away from the head is the connecting surface, the connecting surface is provided with a key, and the irregular side surfaces are composed of two triangular inclined surfaces outwardly protruding; the surface of the main body and the variable head is smoothly connected after butt joint. The application can be used for realizing comprehensive and effective verification of transition prediction models considering multiple complex effects.

Description

Technical Field

[0001] This invention belongs to the field of high-speed transition ground test technology, specifically relating to a high-speed transition polyhedron test model and test method for various complex effects. Background Technology

[0002] Turbulence and transition are among the main factors affecting the flow field environment of aircraft, and are also fundamental fluid mechanics problems that have long plagued the engineering and scientific communities. Turbulence formed after boundary layer transition in high-speed aircraft can significantly increase frictional drag and aerodynamic heating, thereby affecting the aerodynamic and aerothermal characteristics of the aircraft. Therefore, boundary layer transition must be considered in aircraft design. Because boundary layer transition is influenced by numerous factors such as aircraft shape, incoming flow conditions, and surface roughness, the transition process is complex, and accurately predicting transition phenomena has always been a key focus and challenge in high-speed flow field prediction.

[0003] Currently, the empirical correlation formulas in transition prediction models are developed based on low-speed wind tunnel test data. These models are then improved and modified based on simple shapes such as flat plates and cones, making them suitable for simulating high-speed flow transition. However, the application verification of these modified transition prediction models in high-speed, complex flow fields still has shortcomings. The flat plate transition prediction model cannot simulate crossflow effects, and the cone transition prediction model only considers crossflow effects, neglecting the influence of surface roughness and actual ablation surfaces. Therefore, designing a high-speed transition ground test model and method that considers multiple complex effects, and verifying the high-speed transition prediction model based on experimental data, is of great significance for supporting accurate transition prediction in complex flight environments of high-speed aircraft. Summary of the Invention

[0004] To address the limitations of existing technologies in simulating complex factors in transition ground tests, this invention proposes a high-speed transition polyhedral ground test model and method that considers multiple complex effects. This model allows for simultaneous transition ground tests with varying nose bluntness, wall roughness, and realistic ablation morphology, enabling comprehensive and effective verification of the transition prediction model considering multiple complex effects. This provides a reliable means for accurate prediction of transition in complex flight environments of high-speed aircraft.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0006] This invention provides a high-speed transition polyhedral test model for various complex effects. The polyhedral test model adopts a top-bottom and left-right symmetrical configuration, including a main body and a variable head that is inserted into the main body.

[0007] The main body includes a front plane, a rear plane, an upper plane, a lower plane, and four inclined planes; the front and rear planes are vertically arranged, and the front plane has a recessed cavity for docking; the vertical length of the rear plane is greater than the vertical length of the front plane; the upper and lower planes are located above and below the front and rear planes, respectively, forming an angle with the front and rear planes; the two side edges of the upper and lower planes are connected by two inclined planes, and the two inclined planes on each side protrude outward, forming an angle.

[0008] The variable head includes an upper surface, a lower surface, a connecting surface, and two irregular sides; the front edges of the upper and lower surfaces intersect at a certain angle to form the head, the head is rounded, the side away from the head is the connecting surface, the connecting surface is provided with a convex key for docking, and the irregular sides are composed of two triangular bevels protruding outwards.

[0009] After the main body docks with the variable head, the upper and lower surfaces of the variable head and the upper and lower planes of the main body are located on the same plane and smoothly transition. Each irregular side of the variable head and the two oblique planes of the main body on the same side are located on the same plane and smoothly transition.

[0010] Furthermore, the upper surface of the main body is provided with a groove for mounting the ablation sample.

[0011] Furthermore, the radius of the head rounding is no greater than 20mm.

[0012] Furthermore, the included angle between the upper and lower surfaces of the variable head is not less than 20°.

[0013] Furthermore, the angle between the inclined plane of the main body and the adjacent upper or lower plane is less than 155°.

[0014] Furthermore, the variable head length is 10-15% of the length of the polyhedral test model; the distance from the center of the groove to the apex of the head is 20-25% of the length of the polyhedral test model.

[0015] This invention also provides a test method for a high-speed transition polyhedron test model for various complex effects, comprising the following steps:

[0016] S1. Construct a polyhedral experimental model;

[0017] The polyhedral experimental model is designed with a variable head that uses different bluntnesses, where the bluntness is the radius of the head rounding.

[0018] Design a polyhedral experimental model with a variable head using different wall roughnesses;

[0019] A groove is designed on the upper surface of the polyhedral experimental model body for assembling ablation samples;

[0020] S2. Simulation calculations were carried out on polyhedral test models with different head bluntness, different head wall roughness, and with or without ablation samples to obtain the surface heat flow, pressure distribution, transition surface, and transition position of the polyhedral test models under different conditions.

[0021] S3. Based on the heat flow and pressure distribution on the surface of the polyhedral test model, as well as the transition surface and transition location, clarify the measurement method, the selection of measurement equipment, and the layout of the measurement equipment on the surface of the polyhedral test model.

[0022] Furthermore, step S2 specifically includes the following steps:

[0023] For polyhedral test models with smooth walls of different head bluntness and polyhedral test models containing ablation samples, simulation calculation meshes are constructed for each polyhedral test model.

[0024] Using the simulation calculation mesh of each polyhedral test model as input, the roughness of different head wall surfaces is converted into equivalent sand grain height. According to the ground test conditions, laminar flow, turbulent flow and transition are used to carry out simulation calculations to obtain the surface heat flow, pressure distribution, transition surface and transition position of the polyhedral test model under various conditions.

[0025] The variation of the transition position under different head bluntness and different wall roughness was evaluated.

[0026] Furthermore, the simulation calculation mesh adopts a partitioned docking structure mesh, the near-wall mesh orthogonality of the simulation calculation mesh satisfies 70-90°, and the first layer mesh spacing of the simulation calculation mesh is on the order of 1E-5 times the length of the polyhedral test model.

[0027] Furthermore, the measurement methods include point measurement using sensors and area measurement using phosphorescent thermography;

[0028] The measuring device is a sensor, and the selection of the sensor includes specifying the sensor's size, range, and frequency response specifications.

[0029] The density of the sensors is greater at the transition position than at other positions; the sensors are arranged symmetrically about the vertical plane.

[0030] Furthermore, the sensors include a thin-film platinum resistance thermometer and a pulsating pressure sensor, which are used to measure the wall temperature and wall pressure of the polyhedral test model, respectively.

[0031] Furthermore, the radii of the variable head are designed to be 5mm, 10mm, 15mm, and 20mm, respectively.

[0032] Furthermore, the wall roughness of the variable head is designed to be 0μm, 100μm, 200μm, and 400μm, respectively.

[0033] The beneficial effects of this invention compared to the prior art are as follows:

[0034] 1. This invention designs a high-speed polyhedral configuration test model. Compared with the simple configurations such as flat plates and ellipsoids that are mostly used in current transition ground tests, this polyhedral test configuration takes into account the typical nose configuration characteristics of current high-speed lifting body aircraft. Moreover, the transition mechanism of the polyhedral configuration is different from that of simple configurations such as flat plates and ellipsoids. Some new laws and phenomena obtained in the ground test can support subsequent basic research in the field of high-speed transition and provide guidance for the transition application of high-speed aircraft.

[0035] 2. Based on the existing single-factor transition ground test research, this invention has formed a high-speed transition ground test scheme that considers multiple complex effects. The multiple complex effects involved are all typical scenarios in actual engineering. In a batch of ground tests, the influence of multiple complex effects on high-speed transition can be systematically studied. The obtained test data can provide strong support for the verification of transition prediction methods that consider complex effects. Attached Figure Description

[0036] The accompanying drawings, which form part of this specification, are provided to further illustrate embodiments of the invention and, together with the textual description, explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0037] Figure 1 A schematic diagram of a high-speed transition polyhedron experimental model structure for various complex effects provided in a specific embodiment of the present invention;

[0038] Figure 2 A top view of the combined high-speed transition polyhedral test model provided in a specific embodiment of the present invention;

[0039] Figure 3 A flowchart of the test method for a high-speed transition polyhedron test model for various complex effects, provided for a specific embodiment of the present invention;

[0040] Figure 4 High-speed transition flow field diagram of a polyhedral experimental model provided for a specific embodiment of the present invention;

[0041] Figure 5 A schematic diagram of the layout of the measurement sensors for the polyhedral test model provided in a specific embodiment of the present invention;

[0042] The above figures include the following reference numerals:

[0043] 1. Main body; 11. Front plane; 12. Top plane; 13. Upper sloping plane; 14. Lower sloping plane; 15. Groove; 16. Cavity; 2. Variable head; 21. Top surface; 22. Irregular side; 23. Rounded head; 24. Convex key. Detailed Implementation

[0044] Specific embodiments of the present invention will now be described in detail. In the following description, specific details are set forth for purposes of explanation and not limitation, in order to aid in a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced in other embodiments departing from these specific details.

[0045] It should be noted that, in order to avoid obscuring the invention with unnecessary details, only the device structure and / or processing steps closely related to the solution of the invention are shown in the accompanying drawings, while other details that are not closely related to the invention are omitted.

[0046] This invention provides a method for designing high-speed transition ground tests that considers various complex effects, comprising the following steps:

[0047] Step 1: Design an experimental model suitable for studying a variety of complex effects.

[0048] Existing transition prediction models mainly use simplified models of flat plates and pointed cones, which cannot realistically simulate the three-dimensional nose configuration of an aircraft during the experiment. Considering the typical nose configuration characteristics of high-speed aircraft, this invention designs a polyhedral experimental model.

[0049] It should be noted that, for ease of understanding, in this invention, the end of the polyhedral test model facing the incoming flow direction is considered the front, and the end facing away from the incoming flow direction is considered the rear. The upper and lower are the upper and lower positions of the polyhedral test model in the actual installation state during the test process, and the left and right are the two sides along the incoming flow direction of the polyhedral test model in the actual installation state during the test process.

[0050] like Figure 1 , 2As shown, the polyhedral experimental model adopts a symmetrical configuration, including a main body 1 and a variable head 2 inserted into the main body. The main body includes a front plane 11, a rear plane, an upper plane 12, a lower plane, and four inclined planes. The front and rear planes are vertically arranged. The front plane includes a cavity 16 that docks with the variable head. The vertical length of the rear plane is greater than the vertical length of the front plane. The front and rear edges of the upper plane are connected to the upper edges of the front and rear planes, respectively. The upper plane is designed at a certain angle to the front and rear planes. The front and rear edges of the lower plane are connected to the lower edges of the front and rear planes, respectively. The lower plane is designed at a certain angle to the front and rear planes. The upper and lower planes form an included angle. The two side edges of the upper and lower planes are connected by two inclined planes, and the two inclined planes on each side protrude outwards, forming an included angle. The variable head includes an upper surface 21, a lower surface, a connecting surface, and two irregular side surfaces 22. The front edges of the upper and lower surfaces intersect at a certain angle to form the head, which is rounded. The upper and lower surfaces are on the same plane as the upper and lower planes of the main body and transition smoothly. The rear edges of the upper and lower surfaces connect to the upper and lower edges of the connecting surface. The connecting surface includes a convex key 24 that mates with the cavity of the main body. The two irregular side surfaces 22 of the variable head are formed by two triangular inclined planes protruding outwards. Each irregular side surface is on the same plane as the two inclined planes of the main body on the same side and transitions smoothly. After the head is connected to the main body, it forms a horizontal wedge-shaped structure with irregular sides. The upper and lower surfaces and side surfaces transition smoothly to avoid resistance. This structure can effectively simulate the crossflow effect. In addition, a groove 15 is provided on the upper plane of the main body for mounting ablation samples, which can verify the transition effect when ablation materials are present.

[0051] According to the requirements for inducing boundary layer instability modes, the rounded radius of the head of the polyhedral test model should not exceed 20 mm. To minimize the influence of the angle of attack and sideslip angle, the polyhedral test model adopts a symmetrical configuration both vertically and horizontally. To ensure sufficient installation space for experimental measurement equipment (such as sensors), the included angle between the upper and lower surfaces of the polyhedral test model should not be less than 20°. To more effectively stimulate the transverse flow effect and induce transition, the two inclined planes connecting the upper and lower planes should have the ability to generate a large adverse pressure gradient; therefore, the included angle between the two inclined planes and the upper and lower planes should be less than 155°. Using a polyhedral configuration to study the transition mechanism can yield transition laws under various complex effects (including transverse flow, wall roughness, etc.).

[0052] To meet the research needs of different head blunt transitions, a replaceable model head design is adopted. Specifically, 10-15% of the polyhedral test model near the head is selected as a locally replaceable configuration. The variable head and the main body are connected by a plug-in method to maintain the integrity of the test model.

[0053] To investigate the influence mechanism of wall roughness on transition in a polyhedral test model, several variable heads with different wall roughnesses were designed for a specific head bluntness. It is important to note that this invention only employs different roughness designs for the variable heads, thus meeting the experimental verification requirements and avoiding significant changes in crossflow and other effects caused by replacing the entire test model during the experiment.

[0054] By installing real ablation samples on the upper surface of the polyhedral test model, the surface transition phenomenon of the aircraft under high-speed flight conditions can be simulated, and data that is more consistent with actual flight conditions can be obtained.

[0055] Step 2: High-speed transition simulation evaluation based on multiple complex effects.

[0056] For the designed ground test model suitable for studying various complex effects, CFD simulation was used to conduct simulation calculations and analyses on different head bluntness, different head roughness, and whether the wall surface has ablation samples, etc. The heat flow and pressure distribution characteristics of the model surface, as well as the change law of transition profile and transition position, were obtained, which provides guidance for determining the measurement scheme of high-speed transition ground test.

[0057] Step 3: Develop a high-speed transition ground test measurement scheme that considers multiple complex effects.

[0058] Based on the heat flow and pressure distribution characteristics of the polyhedral test model surface obtained by high-speed transition simulation, as well as the heat flow and pressure values ​​of different parts, the selection of measurement sensors (including sensor type and technical indicators such as range and frequency response) and the layout of sensors on the model surface are clarified.

[0059] To comprehensively characterize the transition characteristics of the polyhedral test model and accurately capture the changes in heat flow and pressure before and after the transition, a combination of phosphorescent thermal mapping and point measurement using thin-film platinum resistance thermometers and pulsating pressure sensors was adopted. Taking into account the actual conditions of the wind tunnel and the material properties of the test model, a ground test measurement scheme for high-speed transition that considers multiple complex effects was finally formulated.

[0060] The technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0061] like Figure 3 As shown, the high-speed transition test includes the following steps.

[0062] Step one: Design a polyhedral experimental model suitable for studying various complex effects. This step mainly includes the following four parts:

[0063] (1) Polyhedral geometry design

[0064] Based on research experience in plate transition, and considering the need for basic research while taking into account the typical nose configuration characteristics of high-speed aircraft, a polyhedral experimental model was designed. According to the requirements for inducing boundary layer instability modes, the radius of the model's nose rounding should not exceed 20 mm. To minimize the influence of angle of attack and sideslip angle, the model adopts a vertically and horizontally symmetrical configuration. To ensure sufficient installation space for the experimental measurement sensors, the angle between the upper and lower surfaces should not be less than 20°. To more effectively stimulate the crossflow effect and induce transition, the two inclined planes connecting the upper and lower planes should have the ability to generate a large adverse pressure gradient; therefore, the angle between the two inclined planes and the upper and lower planes should not be less than 25°.

[0065] (2) Design of variable head bluntness scheme

[0066] To meet the needs of research on transition under different head bluntness, a replaceable model head design was adopted. Specifically, the length of the variable head is 10-15% of the length of the polyhedral test model. Four variable heads were designed with rounding radii of 5mm, 10mm, 15mm and 20mm, respectively. During ground tests, different head structural components were replaced to conduct experimental research on the transition characteristics under different head bluntness.

[0067] (3) Design of variable head roughness scheme

[0068] To investigate the influence mechanism of wall roughness on transition in a polyhedral test model, four different wall roughnesses—0 μm, 100 μm, 200 μm, and 400 μm—were designed for a specific head bluntness. During ground testing, the transition characteristics under different head roughnesses were experimentally studied by replacing the head structural components with different roughnesses.

[0069] (4) Design of actual ablation wall surface

[0070] For a polyhedral test model with a specific blunt head and smooth walls, a groove 15 is machined on the upper plane of the polyhedral test model body. The ablated sample after high-temperature ablation is embedded in the groove, realizing experimental research considering the transition characteristics under the actual ablated wall surface. Preferably, the distance from the center of the groove 15 to the vertex of the head is 20-25% of the length of the polyhedral test model, and the width of the groove 15 is the same as that of the upper plane of the polyhedral test model.

[0071] Step two: High-speed transition simulation evaluation based on multiple complex effects. This step mainly includes the following three parts:

[0072] (1) Calculation grid generation for experimental models

[0073] For smooth wall test models with different head bluntness and real ablation wall test models, commercial mesh generation software was used to generate fine partitioned docking structure meshes. Since it is necessary to evaluate the heat flux value and distribution characteristics of the model surface, the orthogonality of the near-wall mesh and the spacing of the first layer mesh must be strictly controlled. The orthogonality of the near-wall mesh meets 70-90°, and the spacing of the first layer mesh should be on the order of 1E-5 of the model length.

[0074] (2) High-speed transition simulation calculation considering multiple complex effects

[0075] Using the generated computational meshes of various polyhedral test models as input, the wall roughness at different scales is converted into equivalent sand grain heights. According to the planned ground test conditions, simulation calculations are carried out using laminar flow, turbulent flow, and transition, respectively, to obtain the surface heat flow and pressure distribution characteristics of the test models under various simulation conditions, as well as the transition location and transition surface characteristics.

[0076] (3) Evaluation of high-speed transition characteristics considering multiple complex effects

[0077] By comparing the wall heat flow distribution characteristics obtained from laminar flow, turbulent flow, and transition simulations under various test conditions, the transition location and transition profile can be determined. Furthermore, the variation law of the transition location under different head bluntness and different wall roughness can be analyzed and evaluated, providing support for the formulation of high-speed transition ground test measurement schemes.

[0078] Step 3: Develop a ground-based test measurement scheme for high-speed transition, considering various complex effects. This step mainly includes the following three parts:

[0079] (1) Selection of measurement methods

[0080] Currently, the comprehensive verification of high-speed transition models mainly focuses on the transition location, post-transition heat flow changes, and pressure pulsations. Therefore, a combination of surface and point measurements can be used for ground-based experimental measurement. Specifically, phosphorescent powder can be sprayed onto the surface of the test model, and infrared thermal images of the model surface can be obtained using optical methods, thereby enabling the identification of the transition location and transition profile. By installing point measurement sensors at typical locations, pressure and heat flow data at the corresponding locations can be acquired, thus supporting the verification of high-speed transition models.

[0081] (2) Selection of measurement sensors

[0082] Based on the values, pulsation amplitudes, and frequencies of parameters such as heat flux and pressure on the wall of the polyhedral test model obtained from high-speed transition simulation evaluation, and combined with parameters such as wind tunnel running time and test model material, the size, range, and frequency response of the measurement sensors were determined, thereby determining the sensor selection. Specifically, a thin-film platinum resistance thermometer was used to measure the model wall temperature, and a pulsating pressure sensor was used to capture the pulsating changes in wall pressure, thereby validating the high-speed transition model.

[0083] (3) Determining the layout of measurement sensors

[0084] Based on the heat flow distribution characteristics of the polyhedral test model wall obtained from high-speed transition simulation evaluation, and the variation law of transition position under different head bluntness and different wall roughness, the test model is arranged according to the principle of denser density along the flow direction and symmetrical arrangement in the circumferential direction. Specifically, the range of transition position variation is determined according to the variation law of transition position, and the sensors are densely deployed along the incoming flow direction within the determined range of transition position variation, so that the sensor density is greater than the sensor density at other locations, and the sensors are symmetrically arranged about the centerline parallel to the incoming flow direction. A certain number of thin-film platinum resistance and pulsating pressure sensors are selected and arranged at typical positions on the upper and lower planes and the two inclined planes on both sides of the polyhedral test model, respectively, to determine the layout of the measurement sensors.

[0085] To demonstrate the effectiveness of a ground-based test scheme that considers various complex effects during high-speed transition, this invention designs a ground-based test scheme for a polyhedral test model. Figure 1 , 2 The design scheme diagram for the experimental model includes a variety of complex effects such as crossflow effect, roughness effect, and real ablation morphology characteristics. Figure 4 The high-speed transition flow field of the test model was obtained by simulation using a transition prediction model that considers crossflow and roughness effects. The transition position on the surface of the test model and the sudden increase in heat flux after the transition can be clearly seen. Figure 5 The types and layout schemes of the sensors used to measure the surface of the test model are as follows. Figure 5 The center line houses the pulsating pressure sensor, while the rest are thin-film platinum resistance sensors. Information such as phosphorescence thermograms, wall heat flow, and pulsating pressure obtained from high-speed transition ground tests considering various complex effects can provide strong support for the verification of high-precision transition models.

[0086] The features described and / or illustrated above for one embodiment may be used in the same or similar manner in one or more other embodiments, and / or in combination with or in lieu of features in other embodiments.

[0087] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, components, or combinations thereof.

[0088] Many features and advantages of these embodiments are apparent from this detailed description, and therefore the appended claims are intended to cover all such features and advantages of these embodiments that fall within their true spirit and scope. Furthermore, since many modifications and alterations will readily occur to those skilled in the art, the embodiments of the invention are not intended to be limited to the precise structures and operations illustrated and described, but rather to encompass all suitable modifications and equivalents falling within their scope.

[0089] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0090] The parts of this invention not described in detail are techniques known to those skilled in the art.

Claims

1. A high-speed transition polyhedron test model for various complex effects, characterized in that, The polyhedral test model adopts a top-bottom and left-right symmetrical configuration, including a main body and a variable head that is inserted into the main body; The main body includes a front plane, a rear plane, an upper plane, a lower plane, and four inclined planes. The front and rear planes are vertically arranged, and the front plane has a recessed cavity for docking. The vertical length of the rear plane is greater than that of the front plane. The front and rear edges of the upper plane are connected to the upper edges of the front and rear planes, respectively, and the upper plane is designed at a certain angle to the front and rear planes. The front and rear edges of the lower plane are connected to the lower edges of the front and rear planes, respectively, and the lower plane is designed at a certain angle to the front and rear planes. The two side edges of the upper and lower planes are connected by two inclined planes, and the two inclined planes on each side protrude outwards, forming an included angle. The variable head includes an upper surface, a lower surface, a connecting surface, and two irregular sides; the front edges of the upper and lower surfaces intersect at a certain angle to form the head, the head is rounded, the side away from the head is the connecting surface, the connecting surface is provided with a convex key for docking, and the irregular sides are composed of two triangular bevels protruding outwards. After the main body docks with the variable head, the upper and lower surfaces of the variable head smoothly transition with the upper and lower planes of the main body, and each irregular side of the variable head smoothly transitions with the two oblique planes of the main body on the same side.

2. The high-speed transition polyhedron test model according to claim 1, characterized in that, The upper surface of the main body is provided with a groove for mounting the ablation sample.

3. The high-speed transition polyhedron test model according to claim 2, characterized in that, The radius of the rounded head is no greater than 20mm; the angle between the upper and lower surfaces of the variable head is no less than 20°; the angle between the inclined plane of the main body and the adjacent upper or lower plane is less than 155°; the length of the variable head is 10-15% of the length of the polyhedral test model; the distance from the center of the groove to the vertex of the head is 20-25% of the length of the polyhedral test model.

4. A test method for a high-speed transition polyhedron experimental model for multiple complex effects, characterized in that, Includes the following steps: S1. Construct a polyhedral experimental model; The polyhedral experimental model is designed with a variable head that has different bluntnesses, where the bluntness is the radius of the head rounding. Design a polyhedral experimental model with a variable head using different wall roughnesses; A groove is designed on the upper surface of the polyhedral experimental model body for assembling ablation samples; S2. Simulation calculations were carried out on polyhedral test models with different head bluntness, different head wall roughness, and with or without ablation samples to obtain the surface heat flow, pressure distribution, transition surface, and transition position of the polyhedral test models under different conditions. S3. Based on the heat flow and pressure distribution on the surface of the polyhedral test model, as well as the transition surface and transition location, clarify the measurement method, the selection of measurement equipment, and the layout of the measurement equipment on the surface of the polyhedral test model.

5. The test method according to claim 4, characterized in that, Step S2 specifically includes the following steps: For polyhedral test models with smooth walls of different head bluntness and polyhedral test models containing ablation samples, simulation calculation meshes are constructed for each polyhedral test model. Using the simulation calculation mesh of each polyhedral test model as input, the roughness of different head wall surfaces is converted into equivalent sand grain height. According to the ground test conditions, laminar flow, turbulent flow and transition are used to carry out simulation calculations to obtain the surface heat flow, pressure distribution, transition surface and transition position of the polyhedral test model under various conditions. The variation of the transition position under different head bluntness and different wall roughness was evaluated.

6. The test method according to claim 5, characterized in that, The simulation calculation mesh adopts a partitioned docking structure mesh, and the near-wall mesh orthogonality of the simulation calculation mesh satisfies 70~90°. The first layer mesh spacing of the simulation calculation mesh is on the order of 1E-5 times the length of the polyhedral test model.

7. The test method according to claim 6, characterized in that, The measurement methods include point measurement using sensors and area measurement using phosphorescent thermography; The measuring device is a sensor, and the selection of the sensor includes specifying the sensor's size, range, and frequency response specifications. The density of the sensors is greater at the transition position than at other positions; the sensors are arranged symmetrically about the vertical plane.

8. The test method according to claim 7, characterized in that, The sensors include a thin-film platinum resistance thermometer and a pulsating pressure sensor, which are used to measure the wall temperature and wall pressure of the polyhedral test model, respectively.

9. The test method according to claim 4, characterized in that, The rounding radii of the heads are designed to be 5mm, 10mm, 15mm, and 20mm, respectively.

10. The test method according to claim 4, characterized in that, The wall roughness of the variable head is designed to be 0μm, 100μm, 200μm, and 400μm, respectively.

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