A flow-adaptive controlled vapor phase evaporation cooling thermal protection system and method

Abstract

This invention discloses a flow-adaptive control gas-phase sweating cooling thermal protection system, comprising a porous structure, a dense material structure, a porous structure cavity, a sweating agent supply pipeline, a pressure regulating device, a sweating agent gas source, and an electronic control system. This invention also discloses a flow-adaptive control gas-phase sweating cooling thermal protection method. In a stable thermal environment, the flow rate q of the sweating agent supplied by the sweating agent gas source is determined based on the aerodynamic heat flow Q outside the porous structure, the aerodynamic pressure P1 outside the porous structure, and the pressure P2 inside the porous structure cavity. In an unstable thermal environment, the changes in Q and P1 at the next moment are predicted, and q is adjusted in advance. Simultaneously, the temperature T of the porous structure is monitored; when T rises above the upper limit of the optimal temperature range, the sweating agent flow rate increment is activated until T drops to the lower limit of the optimal temperature range. This invention can efficiently meet aerodynamic thermal protection requirements with lower sweating agent flow rate requirements and has broad application prospects in the field of aerodynamic thermal protection technology.

Description

Technical Field

[0001] This invention relates to a sweating cooling thermal protection system based on a three-degree-of-freedom collaborative feedback mechanism to achieve adaptive flow control, belonging to the field of aerodynamic thermal protection technology. Background Technology

[0002] Vapor-phase perspiration cooling technology is a highly efficient active thermal protection technology. During perspiration cooling, a perspiration agent flows out from the outer surface of the structure, forming an ejector gas flow, thereby reducing the aerodynamic heating heat flux. Therefore, the aerodynamic heating heat flux can be controlled by controlling the flow rate of the perspiration agent. On the other hand, because perspiration cooling technology requires carrying the perspiration agent and other auxiliary mass, it increases the compensation of the thermal protection system. Therefore, how to meet the aerodynamic thermal protection requirements with low compensation and high efficiency is the key issue of perspiration cooling technology.

[0003] Current sweating cooling technologies often employ a discrete, stepped sweating agent flow supply strategy to cope with constantly changing thermal environments. While effective, this conservative design approach can lead to wasted sweating agent flow at specific times and locations, increasing the compensation required by the thermal protection system. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned defects and provide a gas phase sweating cooling thermal protection system and method with flow adaptive control. This invention solves the technical problem that current sweating cooling technology will waste sweating agent flow at specific times and local locations. This invention can efficiently meet the requirements of aerodynamic thermal protection with lower sweating agent flow requirements and has broad application prospects in the field of aerodynamic thermal protection technology.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a sweating-cooling thermal protection system based on a three-degree-of-freedom collaborative feedback mechanism to achieve adaptive flow control. The system obtains real-time sensing of the aerodynamic heating heat flux (degree of freedom 1), aerodynamic pressure (degree of freedom 2), and structural temperature (degree of freedom 3) on the outside of the heat-protecting structure through three methods: pre-stored data retrieval, real-time data measurement, and rapid iterative calculation. It then adjusts the supply pressure of the sweating agent according to the time-varying characteristics of each degree of freedom. Therefore, compared with previous solutions, this invention can efficiently meet aerodynamic thermal protection requirements with a lower sweating agent flow rate.

[0007] A flow-adaptive controlled vapor phase sweating cooling thermal protection system includes: a porous structure, a dense material structure, a porous internal cavity, a sweating agent supply pipeline, a pressure regulating device, a sweating agent gas source, and an electronic control system.

[0008] A hollow structure is formed by combining a dense material structure with a porous structure, and the internal cavity of the hollow structure is a porous structure cavity.

[0009] The sweating agent gas source located outside the porous structure cavity is connected to the porous structure cavity through a sweating agent supply pipeline. The sweating agent gas source is used to supply sweating agent to the porous structure cavity.

[0010] A pressure regulating device is installed on the sweating agent supply line;

[0011] The electronic control system pre-stores aircraft status data and obtains the aerodynamic heat flow Q and aerodynamic pressure P1 on the outside of the porous structure by looking up the pre-stored aircraft status data in real time from the MAP diagram. At the same time, the electronic control system measures the temperature T and the pressure P2 of the porous structure cavity in real time. Based on the temperature T, the pressure P2, the aerodynamic heat flow Q, and the aerodynamic pressure P1 on the outside of the porous structure, the pressure regulating device is controlled to achieve real-time control of the flow rate q of the sweating agent gas source.

[0012] A flow-adaptive control method for gas-phase evaporation cooling thermal protection, implemented using the aforementioned flow-adaptive control system for gas-phase evaporation cooling thermal protection, includes:

[0013] S1 determines the thermal environment state of the aircraft. If the aircraft is in a stable thermal environment state, proceed to step S2; otherwise, proceed to step S3.

[0014] The S2 electronic control system determines the flow rate q of the sweating agent gas source based on the temperature T of the porous structure 1, the aerodynamic heat flow Q on the outside of the porous structure, the aerodynamic pressure P1 on the outside of the porous structure and the pressure P2 in the cavity of the porous structure, as well as the pre-set temperature control target T_goal of the porous structure.

[0015] The S3 electronic control system predicts the changes in aerodynamic heat flow Q and aerodynamic pressure P1 on the outside of the porous structure at the next moment, and adjusts the flow rate q of the sweating agent gas source in advance based on the prediction results.

[0016] Furthermore, in step S1, the method for determining whether the aircraft is in a stable thermal environment includes:

[0017] If the current time is set as t, and the rate of change of both the aerodynamic heat flux Q and the aerodynamic pressure P1 on the outside of the porous structure are less than or equal to 20% during the time period from t-2s to t+2s, then the spacecraft is considered to be in a stable thermal environment at the current time.

[0018] Furthermore, in step S2, given the aerodynamic heat flow Q on the outside of the porous structure, the aerodynamic pressure P1 on the outside of the porous structure, and the pressure P2 inside the porous structure, the control equations for velocity and density, the Kays model of the sweating heat flow, and the control equation for temperature are solved comprehensively using Q, P1, and P2 as boundary conditions to obtain the supply flow rate q of the sweating agent corresponding to the surface temperature control target T_goal of the porous structure.

[0019] Furthermore, the governing equations for velocity and density are:

[0020]

[0021] p = ρR g T

[0022]

[0023] The Kays model for the diaphoretic cooling flux is as follows:

[0024]

[0025] The governing equation for temperature is:

[0026]

[0027] In the formula, R is the ratio of net heat flux generated by sweating to heat flux generated without sweating, F is the dimensionless outflow rate of the sweating agent in the local area, and St0 is the Stanton number for heat transfer without sweating; t, ρ, p, T,c p S represents time, density, velocity, pressure, external force, temperature, specific heat, and heat source, respectively. The subscripts s and f represent solid and fluid, respectively. ε p ,μ,K D ,K F ,k eff These are porosity, viscosity, Darcy permeability, Forchheimer permeability, and effective thermal conductivity, respectively. R is the identity matrix; ▽ is the Laplace mathematical operator. g is the ideal gas constant.

[0028] Using Q as the outer boundary condition of the temperature control equation and P1 and P2 as the inner and outer pressure boundary conditions of the velocity and density control equations, the perspiration agent flow rate q is obtained.

[0029] In the above temperature control equation, T s That is, the temperature T of the porous structure. This invention lowers the structural temperature by controlling the flow rate of the perspiration agent. In the calculation equation, each flow rate value corresponds to a T. s Value; when T sOnce the value reaches T_goal, the resulting flow rate is the desired value.

[0030] Furthermore, in step S3, the electronic control system pre-stores the aerodynamic heat flow Q and the aerodynamic pressure P1 on the outside of the porous structure at the next moment.

[0031] When Q or P1 increases in the next moment, increase the flow rate and pressure of the diaphoretic agent in advance; when Q or P1 is predicted to decrease, decrease the flow rate and pressure of the diaphoretic agent in advance.

[0032] Furthermore, when performing steps S2 and S3, when the temperature T of the porous structure is greater than or equal to the upper limit of the preset optimal temperature range, the flow rate of the sweating agent is increased based on the original sweating agent supply conditions until the temperature T of the porous structure drops to the lower limit of the optimal temperature range, and the original sweating agent supply conditions are restored.

[0033] Furthermore, the upper limit of the optimal temperature range is determined based on the service temperature of the porous structural material and the safety factor of the engineering design;

[0034] The increase in the diaphoretic agent supply flow rate based on the original diaphoretic agent supply conditions is recorded as the diaphoretic agent supply increment. The optimal temperature range satisfies the following conditions:

[0035] The time period during which the temperature of the porous structure gradually decreases from the upper limit of the optimal temperature range to the lower limit of the optimal temperature range under the effect of the increased supply of diaphoretic agent, and then the increased supply of diaphoretic agent decreases to zero, and the temperature of the porous structure gradually rises from the lower limit of the optimal temperature range to the upper limit of the optimal temperature range is defined as a cycle.

[0036] The method for determining the lower limit of the optimal temperature range within a periodic time period is to find a value that minimizes the average value of the increase in the supply of diaphoretic agent over the entire period.

[0037] Furthermore, a multi-objective optimization method is adopted to obtain the lower limit value of the optimal temperature range under given aerodynamic heat flux and aerodynamic pressure boundary conditions, and at the same time determine the incremental value of the sweating agent supply.

[0038] Furthermore, the target value T_goal for controlling the surface temperature of the pore structure is taken as the upper limit of the optimal temperature range.

[0039] Compared with the prior art, the present invention has at least one of the following advantages:

[0040] (1) This invention provides a flow adaptive control vapor phase sweating cooling thermal protection system, which can sense the three degrees of freedom of heat flow, pressure and structural temperature on the outside of the structure in real time, laying the foundation for meeting the thermal protection requirements of aircraft with lower mass compensation.

[0041] (2) This invention provides a gas phase sweating cooling thermal protection method with flow adaptive control, which takes into account various situations of stable and unstable flight of the aircraft, and achieves the purpose of saving sweating agent on the basis of achieving stable thermal protection effect;

[0042] (3) The present invention obtains the control target of the optimal temperature range based on the multi-objective optimization method, and further avoids the waste of sweating agent by adjusting the supply increment of sweating agent flow rate, thereby effectively improving the engineering application efficiency of sweating agent. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of a flow adaptive control vapor phase sweating cooling thermal protection system according to the present invention. Detailed Implementation

[0044] The features and advantages of the present invention will become clearer and more apparent from the following detailed description.

[0045] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0046] Vapor-phase evaporative cooling technology offers significant advantages in thermal protection. However, traditional stepped evaporative agent supply strategies waste agent mass and increase overall system compensation when dealing with time-varying thermal environments. This invention addresses these issues by real-time sensing of three degrees of freedom: external heat flow, pressure, and structural temperature. It considers both constant and time-varying external thermal environments and structural temperature response characteristics, using the highest structural temperature as a fundamental constraint and reducing evaporative agent mass compensation as its core objective. The invention employs a control method for a pressure regulation device based on "real-time feedback control of net heat flow, real-time monitoring and regulation of structural temperature, and early supply interruption in the face of low back pressure." This new approach can meet the thermal protection requirements of aircraft with significantly lower mass compensation.

[0047] This invention provides an engineered control technology solution for sweating and cooling.

[0048] High-speed flight of aircraft encounters aerodynamic heating, causing structural temperatures to rise and exceed material limits. Sweat cooling technology is a highly efficient thermal protection technique that safeguards the structural safety of high-speed aircraft during flight.

[0049] The principle of sweating cooling technology is to design the outer shell structure as a porous structure, allowing the sweating agent to flow out from the inside to the outside through the porous structure. When the sweating agent flows out of the porous structure at a certain flow rate, it can directly reduce the aerodynamic heating heat flux, thus protecting the aircraft shell structure. At the same time, when the sweating agent flows through the heated porous structure, it can also carry away the heat of the porous structure through convection, reducing the temperature of the porous structure and forming a second protection mechanism for the aircraft shell structure.

[0050] This invention discloses a flow-adaptive control gas phase sweating cooling thermal protection system, comprising a porous structure, a dense material structure, a porous internal cavity, a sweating agent supply pipeline, a pressure regulating device, a sweating agent gas source, and an electronic control system. This invention also discloses a flow-adaptive control method for vapor-phase sweating cooling thermal protection. The method includes determining the flight thermal environment state of the aircraft. When the aircraft is in a stable thermal environment, the flow rate q of the sweating agent supplied by the sweating agent gas source is determined based on the aerodynamic heat flow Q on the outside of the porous structure, the aerodynamic pressure P1 on the outside of the porous structure, and the pressure P2 inside the porous structure. In an unstable thermal environment, the changes in Q and P1 on the outside of the porous structure at the next moment are predicted, and the flow rate q of the sweating agent supplied by the sweating agent gas source is adjusted in advance based on the prediction results. Simultaneously, in both stable and unstable thermal environments, the temperature T of the porous structure is monitored. When T rises above the upper limit of the optimal temperature range, the sweating agent flow rate increment is activated until T drops to the lower limit of the optimal temperature range. The lower limit of the optimal temperature range is determined by using a multi-objective optimization method to ensure the lowest average hourly consumption rate of the sweating agent flow rate. This invention can efficiently meet aerodynamic thermal protection requirements with lower sweating agent flow rate requirements and has broad application prospects in the field of aerodynamic thermal protection technology.

[0051] like Figure 1 This invention provides a flow-adaptive controlled vapor-phase sweating cooling thermal protection system, comprising a porous structure 1, a dense material structure 2, a porous structure inner cavity 3, a sweating agent supply pipeline 4, a pressure regulating device 5, a sweating agent gas source 6, and an electronic control system 7. The electronic control system 7 stores state parameters of the thermal environment and aerodynamic pressure at different times and can measure the temperature and inner cavity pressure of the porous structure in real time. The electronic control system 7 achieves the sensing of heat flow, pressure, and temperature on the outside of the porous structure through three methods: comprehensive retrieval of pre-stored data, measurement of real-time data, and rapid iterative calculation. The dense material structure 2 is closely attached to the outside of the aircraft shell, and the porous structure 1 is located outside the dense material structure 2.

[0052] This invention also provides a flow-adaptive control method for vapor-phase sweating cooling thermal protection, specifically including:

[0053] When the aircraft is flying stably, the aerodynamic heating heat flow and aerodynamic pressure on the outer surface of the porous structure are relatively stable. At this time, the flow rate of the sweating agent can be controlled at a stable level, achieving a stable thermal protection effect.

[0054] In this state, the method for calculating and determining the perspiration agent flow rate is as follows:

[0055] System of equations 1:

[0056]

[0057] p = ρR g T

[0058]

[0059] System of equations 2:

[0060]

[0061] System of equations 3:

[0062]

[0063] Equation 1 is the governing equation for velocity and density, which describes the flow process of the sweating agent in the porous shell structure. Under the condition of known inner and outer pressures, the outflow rate and distribution of the sweating agent on the outer surface of the porous shell can be obtained by solving the equation.

[0064] Equation 2 is the Kays model, which calculates the heat flux from sweating. It describes the heat flux process of the sweating agent ejected outflow. By knowing the outflow flow rate distribution of the sweating agent and the heat flux distribution on the structural surface when there is no sweating, the net heat flux and its distribution on the structural surface when the sweating agent is ejected can be obtained. In the equation, R is the ratio of the net heat flux from sweating to the heat flux without sweating, and F is the dimensionless outflow flow rate of the sweating agent in the local area.

[0065] Equation 3 is the governing equation for temperature, which describes the heat transfer process between the porous structure and the internal flow of the sweating agent. By knowing the boundary conditions of the net heat flow on the outside, the outflow temperature and its distribution of the sweating agent on the outer surface of the porous shell can be obtained, and the temperature field of the porous shell can be obtained.

[0066] The symbols for all three systems of equations use the notation commonly used in engineering.

[0067] By comprehensively solving equations 1, 2, and 3, and taking the aerodynamic heat flow Q and aerodynamic pressure P1 on the outside of porous structure 1 as the boundary conditions, the supply flow rate q of the perspiration agent corresponding to the surface temperature control target T_goal of the porous structure can be obtained.

[0068] The target temperature T_goal for controlling the surface temperature of the porous structure should be within the optimal temperature range described later; preferably, its value can be selected as the upper limit of the optimal temperature range.

[0069] When an aircraft experiences unstable states such as significant acceleration and attitude changes, the aerodynamic heating heat flux and aerodynamic pressure on the outer surface of the porous structure will also change significantly. The technical solution for sweating cooling control under these changing conditions is as follows:

[0070] Based on predicted information about aerodynamic heat flow and pressure, actions are taken in advance. When an increase in aerodynamic heat flow is predicted, the flow rate of the diaphoretic agent is increased in advance to improve thermal stability; when a decrease in aerodynamic heat flow is predicted, the flow rate of the diaphoretic agent is decreased in advance to save on the amount of diaphoretic agent used. When an increase in aerodynamic pressure is predicted, the supply pressure of the diaphoretic agent is increased in advance to avoid a short-term shortage of diaphoretic agent supply after the pressure increases; when a decrease in aerodynamic pressure is predicted, the supply pressure of the diaphoretic agent is decreased in advance to fully utilize the residual pressure release within the diaphoretic agent cavity, thereby saving on the amount of diaphoretic agent used.

[0071] The predicted information for aerodynamic heat flux and aerodynamic pressure comes from retrieving pre-stored data. The calculation and control module pre-stores database information such as the aircraft's trajectory, flight attitude, and time, as well as distribution data of aerodynamic heat flux and aerodynamic pressure. During flight, real-time data values ​​can be obtained through retrieval and calculation. This enables the prediction of aerodynamic heat flux and aerodynamic pressure.

[0072] During the control process under the aforementioned stable and unstable states, the temperature at key locations of the porous structure is simultaneously measured in real time. These key locations can be the highest temperature location, the temperature point of a weak structure, etc. The temperature T of the porous structure 1 measured in real time by the electronic control system 7 is the temperature at that key location. Sweating cooling can reduce heat flux to a certain extent, but it cannot completely reduce the aerodynamic heat flux to zero. Therefore, under the influence of the net heat flux after sweating, the temperature of the porous structure continues to increase. At this time, by measuring the structure temperature in real time, when the measured peak temperature reaches the upper limit of the "optimal temperature range," the flow rate of the sweating agent is increased based on the original sweating agent supply conditions. That is, the incremental sweating agent flow rate is activated to achieve cooling control of the structure until the peak temperature drops to the lower limit of the optimal temperature range, at which point the incremental sweating agent flow rate is stopped.

[0073] This introduces a new concept: "optimal temperature control range." While sweating cooling can lower the structural temperature, setting the temperature target too low is detrimental to utilizing the radiative heat dissipation capacity of the structure's outer surface (radiative heat flux is a function of the fourth power of surface temperature; a low surface temperature results in low radiative heat dissipation capacity), leading to a waste of the sweating agent. Therefore, a maximum temperature control range is needed to avoid wasting the sweating agent.

[0074] The upper limit of the interval is determined by combining the service temperature of the material and taking into account the safety factor of the designer's engineering design. The lower limit of the interval is determined by the following method: under the effect of the incremental supply of sweating agent, the highest temperature of the structure gradually decreases from the upper limit of the interval to the lower limit of the interval. Then, the incremental supply of sweating agent drops to zero, and the temperature of the structure gradually rises from the lower limit of the interval to the upper limit of the interval. During this periodic time period, the time average value of the incremental supply of sweating agent is the minimum. At this time, the lower limit of the interval is the optimal lower limit of the interval. The lower limit of the interval and the upper limit of the interval together constitute the optimal temperature control interval.

[0075] The calculation and determination of the incremental supply of the diaphoretic agent flow rate are performed simultaneously with the calculation of the lower limit of the aforementioned "optimal temperature control range." Essentially, this is a multi-objective optimization problem under given aerodynamic heat flux and aerodynamic pressure boundary conditions. The results dataset can be pre-calculated using a high-performance computer in parallel and stored in a database for real-time querying and retrieval.

[0076] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0077] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A flow-adaptive controlled vapor-phase sweating cooling thermal protection system, characterized in that, include: Porous structure (1), dense material structure (2), porous structure cavity (3), sweating agent supply pipeline (4), pressure regulating device (5), sweating agent gas source (6) and electronic control system (7); The dense material structure (2) and the porous structure (1) are combined to form a hollow structure, and the internal cavity of the hollow structure is the porous structure cavity (3); The sweating agent gas source (6) located outside the porous structure cavity (3) is connected to the porous structure cavity (3) through the sweating agent supply pipeline (4). The sweating agent gas source (6) is used to supply sweating agent to the porous structure cavity (3). A pressure regulating device (5) is provided on the sweating agent supply pipeline (4); The electronic control system (7) pre-stores the aircraft status data and obtains the aerodynamic heat flow Q and aerodynamic pressure P1 on the outside of the porous structure (1) by looking up the MAP diagram in real time from the pre-stored aircraft status data. The electronic control system (7) simultaneously measures the temperature T of the porous structure (1) and the pressure P2 of the inner cavity (3) of the porous structure in real time. Based on the temperature T of the porous structure (1), the pressure P2 of the inner cavity (3) of the porous structure, the aerodynamic heat flow Q and the aerodynamic pressure P1 on the outside of the porous structure (1), the pressure regulating device (5) is controlled to achieve real-time control of the sweating agent flow rate q supplied by the sweating agent gas source (6).

2. A method for heat protection through vapor-phase sweating cooling with adaptive flow control, characterized in that, The system employs a flow-adaptive control vapor phase sweating cooling thermal protection system as described in claim 1, comprising: S1 determines the thermal environment state of the aircraft. If the aircraft is in a stable thermal environment state, proceed to step S2; otherwise, proceed to step S3. The S2 electronic control system (7) determines the flow rate q of the sweating agent gas source (6) based on the temperature T of the porous structure (1), the aerodynamic heat flow Q outside the porous structure (1), the aerodynamic pressure P1 outside the porous structure (1) and the pressure P2 inside the porous structure (3), as well as the pre-set temperature control target T_goal of the porous structure. The S3 electronic control system (7) predicts the changes in the aerodynamic heat flow Q and aerodynamic pressure P1 outside the porous structure (1) at the next moment, and adjusts the sweating agent gas source (6) to supply the sweating agent flow rate q in advance according to the prediction results.

3. The method for heat protection through vapor phase sweating cooling with adaptive flow control according to claim 2, characterized in that, In step S1, the method for determining whether the aircraft is in a stable thermal environment includes: If the current time is set as t, and the rate of change of the aerodynamic heat flow Q and the aerodynamic pressure P1 on the outside of the porous structure (1) are both less than or equal to 20% during the time period from t-2s to t+2s, then the aircraft is considered to be in a stable thermal environment at the current time.

4. The method for heat protection through vapor phase sweating cooling with adaptive flow control according to claim 2, characterized in that, In step S2, given the aerodynamic heat flow Q on the outside of the porous structure (1), the aerodynamic pressure P1 on the outside of the porous structure (1), and the pressure P2 in the inner cavity (3) of the porous structure, the control equations for velocity and density, the Kays model of the sweating heat flow, and the control equation for temperature are solved by taking Q, P1, and P2 as boundary conditions. The flow rate q of the sweating agent corresponding to the surface temperature control target T_goal of the porous structure is obtained.

5. The method for heat protection of vapor phase sweating cooling with adaptive flow control according to claim 4, characterized in that, The governing equations for velocity and density are: p6ρR g T The Kays model for the diaphoretic cooling flux is as follows: The governing equation for temperature is: In the formula, R is the ratio of net heat flux generated by sweating to heat flux generated without sweating, F is the dimensionless outflow rate of the sweating agent in the local area, and St0 is the Stanton number for heat transfer without sweating; t, ρ, p, T,c p S represents time, density, velocity, pressure, external force, temperature, specific heat, and heat source, respectively. The subscripts s and f represent solid and fluid, respectively. ε p ,μ,K D ,K F ,k eff These are porosity, viscosity, Darcy permeability, Forchheimer permeability, and effective thermal conductivity, respectively. It is the identity matrix; R is the Laplace mathematical operator. g It is the ideal gas constant; Using Q as the outer boundary condition of the temperature control equation, and P1 and P2 as the inner and outer pressure boundary conditions of the velocity and density control equations, the perspiration agent flow rate q corresponding to the surface temperature control target T_goal of the porous structure is obtained.

6. The method for heat protection through vapor phase sweating cooling with adaptive flow control according to claim 2, characterized in that, In step S3, the electronic control system (7) pre-stores the aerodynamic heat flow Q and the aerodynamic pressure P1 on the outside of the porous structure (1) at the next moment. When Q or P1 increases in the next moment, increase the flow rate of the diaphoretic agent in advance; when Q or P1 is predicted to decrease, decrease the flow rate of the diaphoretic agent in advance.

7. The method for gas-phase sweating cooling thermal protection with adaptive flow control according to claim 4, characterized in that, When performing steps S2 and S3, when the temperature T of the porous structure (1) is greater than or equal to the upper limit of the preset optimal temperature range, the flow rate of the sweating agent is increased based on the original sweating agent supply conditions until the temperature T of the porous structure (1) drops to the lower limit of the optimal temperature range, and the original sweating agent supply conditions are restored.

8. The method for heat protection of vapor phase evaporation cooling with adaptive flow control according to claim 7, characterized in that, The upper limit of the optimal temperature range is determined based on the service temperature of the porous material and the safety factor of the engineering design. The increase in the diaphoretic agent supply flow rate based on the original diaphoretic agent supply conditions is recorded as the diaphoretic agent supply increment. The optimal temperature range satisfies the following conditions: The time period during which the temperature of the porous structure (1) gradually decreases from the upper limit of the optimal temperature range to the lower limit of the optimal temperature range under the action of the increased supply of sweating agent, and then the increased supply of sweating agent is reduced to zero, and the temperature of the porous structure (1) gradually rises from the lower limit of the optimal temperature range to the upper limit of the optimal temperature range is defined as a cycle. The method for determining the lower limit of the optimal temperature range within a periodic time period is to find a value that minimizes the average value of the increase in the supply of diaphoretic agent over the entire period.

9. A flow-adaptive control method for vapor-phase sweating cooling thermal protection according to claim 8, characterized in that, Using a multi-objective optimization method, under given aerodynamic heat flux and aerodynamic pressure boundary conditions, the lower limit value of the optimal temperature range is obtained, and the incremental value of the sweating agent supply is determined at the same time.

10. A flow-adaptive control method for vapor-phase sweating cooling thermal protection according to claim 9, characterized in that, The target value T_goal for controlling the surface temperature of the porous structure is taken as the upper limit of the optimal temperature range.

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