Active sweating cooling transient thermal response analysis method

Abstract

The invention provides an active sweating cooling transient thermal response analysis method. The method comprises the steps of flight environment aerodynamic thermal analysis of a part needing to be cooled, surface cooling medium distribution characteristic analysis of a cooling part, aerodynamic heating heat flow calculation under the cooling condition, recovery enthalpy calculation under the cooling condition and sweating cooling process transient thermal response analysis. By considering the influence of gas injection on aerodynamic heating heat flow and recovery enthalpy, an active sweating cooling transient thermal response calculation method is developed based on a porous material non-thermal equilibrium model, and a sweating cooling transient thermal response analysis method based on the porous material non-thermal equilibrium model is developed. The thermal response calculation precision of the active sweating cooling structure is improved at a low calculation cost, and support is provided for engineering application of sweating cooling.

Description

Technical Field

[0001] The present invention belongs to the technical field of transient thermal response analysis of active transpiration cooling structures under strong aerodynamic heating, and particularly relates to a method for analyzing the transient thermal response of active transpiration cooling. Background Art

[0002] The requirement for a high lift-to-drag ratio configuration of near-space hypersonic vehicles results in a sharp leading edge characteristic. Thermal protection structures / functional components such as the leading edge of the vehicle head, the leading edge of the wing rudder, the overflow port of the inlet, the internal flow path of the engine, and the fuel injection support plate are facing a harsh service environment of ultra-high temperature and strong oxidation. The corresponding thermal protection technologies are also facing increasingly severe challenges. Currently, conventional thermal protection / cooling measures are increasingly difficult to meet the increasingly stringent thermal protection requirements.

[0003] Among various active cooling methods, transpiration cooling based on porous media has the highest cooling efficiency and is one of the most promising advanced cooling methods at present. The complete transpiration cooling process includes two aspects. First is the flow and heat transfer process occurring inside the porous media. Second is the interaction between the cooling medium and the mainstream on the high-temperature hot end surface, forming a cold gas boundary layer with a certain heat insulation effect. These two aspects interact with each other and have an important impact on the transpiration cooling effect, posing higher requirements for the thermal response analysis method of the transpiration cooling structure. In addition, due to the large flight airspace and wide speed range of hypersonic vehicles, and the large changes in flight attitude and oncoming flow environment, transpiration cooling needs to experience a complex transient response process. It is necessary to develop targeted transient thermal response calculation technology for transpiration cooling to improve the thermal response calculation accuracy of active transpiration cooling structures at a relatively low computational cost and provide support for the engineering application of transpiration cooling. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0005] The present invention provides a method for analyzing the transient thermal response of active transpiration cooling, which includes:

[0006] Step 1: Analyze the aerodynamic heat of the flight environment of the part to be cooled;

[0007] Step 2: Analyze the distribution characteristics of the cooling medium on the surface of the cooling part: Load the surface pressure distribution of the part to be cooled on the surface of the cooling component, and conduct a flow resistance characteristic analysis based on the porous media flow and heat transfer model to obtain the distribution characteristics of the cooling medium flow rate on the surface of the cooling part;

[0008] Step 3: Calculate the aerodynamic heating heat flux under cooling conditions: Obtain the influence amount of the heat blockage effect on the aerodynamic heat according to the dimensionless heat transfer coefficient theoretical relationship of the heterogeneous gas entrainment boundary layer;

[0009] Step 4: Calculate the recovery enthalpy under cooling conditions: Obtain the recovery enthalpy of the cooled part under cooling conditions based on the influence of the heat absorption of the cooling medium on the recovery enthalpy of the material surface.

[0010] Step 5: Analyze the transient thermal response during transpiration cooling: Conduct transient numerical simulation analysis of the flow and heat transfer inside the porous material structure based on the thermal environment considering the thermal blockage effect.

[0011] Applying the technical solution of the present invention provides a method for analyzing the transient thermal response of active transpiration cooling. By considering the influence of gas entrainment on the aerodynamic heating heat flux and recovery enthalpy, a calculation method for the transient thermal response of active transpiration cooling is developed based on the non-thermal equilibrium model of porous materials, and an analysis method for the transient thermal response of transpiration cooling based on the non-thermal equilibrium model of porous materials is developed, which improves the calculation accuracy of the thermal response of the active transpiration cooling structure at a relatively low computational cost. Compared with the prior art, the technical solution of the present invention can solve the technical problem that the existing thermal response analysis technology of active transpiration cooling structures cannot meet the application requirements. Brief Description of the Drawings

[0012] The included drawings are used to provide a further understanding of the embodiments of the present invention, which form a part of the specification, are used to illustrate the embodiments of the present invention, and are used to explain the principles of the present invention together with the text description. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0013] Figure 1 Shows a schematic flow chart of the method for analyzing the transient thermal response of active transpiration cooling provided according to a specific embodiment of the present invention. Detailed Embodiments

[0014] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way limits the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0015] It should be noted that the terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0016] Unless otherwise specifically stated, the relative arrangements of the components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for the sake of convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies, methods, and devices should be regarded as part of the specification. In all the examples shown and discussed herein, any specific values should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, further discussion thereof is not required in subsequent drawings.

[0017] As Figure 1 shown, according to a specific embodiment of the present invention, a method for analyzing the transient thermal response of active sweating cooling is provided, and the method includes:

[0018] Step 1, analyze the aerodynamic heat of the flight environment of the part to be cooled;

[0019] Step 2, analyze the distribution characteristics of the cooling medium on the surface of the cooling part: load the surface pressure distribution of the part to be cooled on the surface of the cooling component, and carry out a flow resistance characteristic analysis based on the porous medium flow and heat transfer model to obtain the distribution characteristics of the cooling medium flow rate on the surface of the cooling part;

[0020] Step 3, calculate the aerodynamic heating heat flux under cooling conditions: obtain the influence amount of the thermal choking effect on the aerodynamic heat according to the dimensionless heat transfer coefficient theoretical relationship of the heterogeneous gas entrainment boundary layer;

[0021] Step 4, calculate the recovery enthalpy under cooling conditions: obtain the recovery enthalpy of the cooling part under cooling conditions based on the influence of the heat absorption of the cooling medium on the recovery enthalpy of the material surface;

[0022] Step 5, analyze the transient thermal response of the sweating cooling process: carry out a transient numerical simulation analysis of the flow and heat transfer inside the porous material structure based on the thermal environment considering the thermal choking effect.

[0023] By applying this configuration method, an active transpiration cooling transient thermal response analysis method is provided. This method develops an active transpiration cooling transient thermal response calculation method based on the non-thermal equilibrium model of porous materials by considering the influence of gas entrainment on aerodynamic heating heat flux and recovery enthalpy, and develops a transpiration cooling transient thermal response analysis method based on the non-thermal equilibrium model of porous materials, so as to improve the thermal response calculation accuracy of the active transpiration cooling structure at a relatively small computational cost.

[0024] First, in the present invention, step one is executed to analyze the aerodynamic heat of the part to be cooled in the flight environment.

[0025] As a specific embodiment of the present invention, a thermal environment analysis of the severe thermal environment part is carried out based on the flight profile, where the oncoming flow parameters are determined according to the flight profile. The cold wall boundary condition (wall temperature T w = 280K) is given on the surface of the aircraft object, and the aerodynamic thermal environment Q s and the pressure distribution data P s of the material surface of the part to be cooled are obtained; the adiabatic wall surface is given on the surface of the aircraft object, and the recovery enthalpy H r of the material surface of the part to be cooled is obtained.

[0026] Furthermore, in the present invention, step two is executed to analyze the distribution characteristics of the cooling medium on the surface of the cooling part: the pressure distribution on the surface of the part to be cooled is loaded on the surface of the cooling component, and the flow resistance characteristics analysis is carried out based on the porous medium flow and heat transfer model to obtain the distribution characteristics of the cooling medium flow rate on the surface of the cooling part.

[0027] As a specific embodiment of the present invention, the flow resistance characteristics analysis inside the porous material in the transpiration cooling scheme is carried out based on the pressure distribution characteristics of the part to be cooled, where the specified pressure distribution P s is given at the outlet of the cooling medium, the cooling medium flow rate is given at the inlet of the cooling medium, and parameters such as the porosity, permeability, thermal conductivity, specific surface area inside the material, and convective heat transfer coefficient of the porous material are given according to the material measurement results. By solving the flow equation inside the porous material, the distribution characteristics of the mass flow rate per unit mass ρ c u c of the cooling medium on the surface of the cooling part are obtained.

[0028] Furthermore, in the present invention, step three is executed to calculate the aerodynamic heating heat flux under the cooling condition: the influence amount of the thermal choking effect on the aerodynamic heat is obtained according to the dimensionless heat transfer coefficient theoretical relationship of the heterogeneous gas entrainment boundary layer.

[0029] As a specific embodiment of the present invention, the aerodynamic heating heat flux Q reduce under the cooling condition is obtained based on the distribution characteristics of the blowing ratio of the cooling medium on the surface of the cooling part:

[0030]

[0031] Among them, H r,film is the surface recovery enthalpy of the porous wall; H r is the recovery enthalpy without cooling; is the wall enthalpy; C p,f and C p,g are the specific heat capacities of the mainstream and the cooling medium respectively; F is the blowing ratio, ρ g and u g are the density and velocity of the mainstream gas respectively, ρ c and u c are the density and velocity of the cooling medium respectively; St uncool is the Stanton number without cooling,

[0032] Furthermore, in the present invention, step four is executed to calculate the recovery enthalpy under the cooling condition: based on the influence of the heat absorption of the cooling medium on the surface recovery enthalpy of the material, the recovery enthalpy of the cooled part under the cooling condition is obtained.

[0033] As a specific embodiment of the present invention, when the radiation effect and the solid heat conduction effect do not need to be considered, the enthalpy value corresponding to the highest temperature that the solid wall can reach is the recovery enthalpy. At this time, the heat is completely dissipated by the heat absorption of the heat capacity of the cooling medium. The energy balance equation of the area to be cooled is:

[0034]

[0035] Among them, α is the convective heat transfer coefficient; and Cp f are the flow rate and specific heat capacity of the cooling medium respectively; T r,film is the temperature corresponding to H r,film ; T is the temperature.

[0036] The surface recovery enthalpy of the cooled porous wall can be obtained by iterative solution

[0037] In the present invention, the distribution analysis of the surface cooling medium of the cooled part is carried out in steps two, three, and four, and by considering the influence amount of gas entrainment on aerodynamic heating, the heat flux and recovery enthalpy distribution characteristics of the component surface under the cooling condition are obtained.

[0038] Furthermore, in the present invention, step five is executed to analyze the transient thermal response of the transpiration cooling process: based on the thermal environment considering the thermal blockage effect, the transient numerical simulation analysis of the flow and heat transfer inside the porous material structure is carried out.

[0039] As a specific embodiment of the present invention, a thermal non-equilibrium model is adopted for the porous medium region. The thermal environment is directly loaded on the solid wall of the porous material and transferred to the cooling medium through the interior of the porous material until the aerodynamic heating is completely dissipated. The heat flux Q reduce , recovery enthalpy H r,film are loaded on the solid wall of the porous medium. Meanwhile, the outward radiation and the convective heat transfer of the cooling medium to the solid skeleton are considered to obtain the transient thermal response data of the complex-shaped cooling structure.

[0040] Through the above steps, a transient thermal response analysis method for transpiration cooling based on the non-thermal equilibrium model of porous materials can be established.

[0041] The present invention overcomes the differences in the thermal response analysis technology of the existing active transpiration cooling structure. By considering the influence of gas entrainment on the aerodynamic heating heat flux and recovery enthalpy, a transient thermal response calculation method for active transpiration cooling is developed based on the non-thermal equilibrium model of porous materials, and a transient thermal response analysis method for transpiration cooling based on the non-thermal equilibrium model of porous materials is developed to improve the thermal response calculation accuracy of the active transpiration cooling structure at a relatively small computational cost, providing support for the engineering application of transpiration cooling.

[0042] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for analyzing transient thermal response of active sweating cooling, characterized in that: The active sweating cooling transient thermal response analysis method comprises: Step 1: Analyze the aerodynamic heat of the flight environment of the part that needs cooling; Step 2: Analyze the distribution characteristics of the cooling medium on the surface of the cooling part: load the surface pressure distribution of the part to be cooled on the surface of the cooling component, perform flow resistance characteristic analysis based on the porous medium flow and heat transfer model, and obtain the cooling medium flow distribution characteristics on the surface of the cooling part; Step 3: Calculate the aerodynamic heating heat flux under cooling conditions: Obtain the influence of thermal blocking effect on aerodynamic heat according to the dimensionless heat transfer coefficient theoretical relationship of the heterogeneous gas induced boundary layer; Step 4: Calculate the recovery enthalpy under cooling conditions: Based on the effect of the heat absorption of the cooling medium on the recovery enthalpy of the material surface, obtain the recovery enthalpy of the cooling part under cooling conditions; Step 5: Analyze the transient thermal response of the sweating cooling process: Conduct transient numerical simulation analysis of the flow and heat transfer inside the porous material structure based on the thermal environment considering the thermal blocking effect.

2. The active sweat cooling transient thermal response analysis method according to claim 1, characterized in that: In step 3, the aerodynamic heating heat flux Q under cooling conditions is obtained based on the distribution characteristics of the cooling medium blowing ratio on the surface of the cooling part. reduce : Among them, Q s H is the aerodynamic thermal environment of the cooling part material surface; r,film is the surface recovery enthalpy of the porous wall; H r is the recovery enthalpy without cooling; is the wall enthalpy; C p,f and C p,g are the specific heat capacities of the mainstream and cooling medium respectively; F is the blowing ratio, ρ g and u g are the density and velocity of the mainstream gas, ρ c and u c are the density and velocity of the cooling medium respectively; St uncool is the uncooled Stanton number, 3. The active sweat cooling transient thermal response analysis method according to claim 2, characterized in that: In step 4, the energy balance equation for the area to be cooled is: Where α is the convective heat transfer coefficient; and Cp f are cooling medium flow rate and specific heat capacity respectively; T r,film H r,film The corresponding temperature; T is the temperature; The surface recovery enthalpy of the porous wall after cooling is obtained by iterative solution 4. The active sweat cooling transient thermal response analysis method according to claims 1 to 3, characterized in that: In step 5, the thermal non-equilibrium model is used in the porous medium area. The thermal environment is directly loaded on the solid wall of the porous material and transferred to the cooling medium through the porous material until the aerodynamic heating is completely dissipated. The heat flux Q under cooling conditions is reduce , recovery enthalpy H r,film It is loaded on the solid wall of the porous medium, and the outward radiation and the convective heat transfer of the cooling medium on the solid skeleton are considered at the same time to obtain the transient thermal response data of the cooling structure with complex shape.

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