A method and system for rapid evaluation of transpiration cooling working fluid outflow state

Abstract

To address the boundary condition problem of the working fluid outflow state in coupled internal and external flow simulations, this invention provides a rapid evaluation method for the outflow state of the sweating cooling working fluid, including: based on the cooling working fluid inlet flow rate on the hot-end component of the aircraft and the saturation temperature... T sat Calculate the critical heat flux of the cooling working fluid in pure liquid phase outflow based on the corresponding enthalpy value and the enthalpy value corresponding to the working fluid inlet temperature; and restore the enthalpy based on the cooling working fluid inlet flow rate. h re Target temperature of hot end components T w Corresponding wall enthalpy and latent heat of phase transition of working fluid H vl Calculate the critical heat flux of the cooling medium in pure gas phase outflow using enthalpy and enthalpy values; compare the surface heat flux of the hot-end components. Q w Critical heat flux of pure liquid phase outflow of cooling working fluid Q 1. Critical heat flux of pure gas phase outflow Q 2. Size; Adjust the inlet flow rate of the cooling working fluid on the hot end components of the aircraft according to the determined cooling working fluid outflow state.

Description

Technical Field

[0001] This invention relates to a method and system for rapid assessment of the outflow state of a sweating cooling working fluid, belonging to the field of cooling. Background Technology

[0002] When an aircraft flies at high speed within the atmosphere, it experiences intense friction with the surrounding air and strong compression of the air in front. Under the combined effects of viscous dissipation and shock wave compression, a large amount of kinetic energy from the high-speed incoming flow is converted into internal energy, causing the temperature within the shock layer to rise sharply, reaching over 10,000 K, resulting in severe aerodynamic heating of the aircraft surface. Therefore, it is essential to develop advanced thermal protection systems to overcome the "thermal barrier" challenge in the development of high-speed aircraft. Active thermal protection technology is a key technology for overcoming the "thermal barrier" problem. For the design of active thermal protection systems, multiphysics coupling simulation analysis is required for the internal flow field and high-speed external flow field of hot-end components under the influence of cooling fluid flow / heat transfer / phase change. The outflow of the cooling fluid is the interface between the internal and external flow fields, so an accurate assessment of the outflow state of the cooling fluid is necessary to provide boundary conditions for the coupled simulation of internal and external flows. Summary of the Invention

[0003] The technical problem to be solved by this invention is: addressing the boundary condition problem of the working fluid outflow state in the internal and external flow coupling simulation, this invention provides a rapid evaluation method and system for the outflow state of the sweating cooling working fluid. Based on the aerodynamic thermal environment and the working fluid flow rate, the outflow state of the working fluid is rapidly evaluated, and the outflow state parameters of the cooling working fluid under specific thermal environment and flow rate can be obtained efficiently.

[0004] The technical solution adopted in this invention is: a method for rapid evaluation of the outflow state of a sweating cooling working fluid, comprising: S1. Based on the external flow conditions, perform aerodynamic and thermal numerical simulation of the external flow field of the hot-end components of the aircraft to obtain the surface heat flux of the hot-end components. Q w Surface pressure P w and recovery enthalpy h re ; S2, based on the surface heat flow of the hot end component Q w and recovery enthalpy h re Determine the coolant inlet flow rate on the hot-end components of the aircraft. ; S3, based on the surface pressure of the hot end component P w In addition to the thermodynamic properties of the cooling medium, the surface pressure of the cooling medium is calculated. P w The corresponding saturation temperature Tsat saturation temperature T sat Corresponding enthalpy value Latent heat of phase transition of working fluid H vl and working fluid inlet temperature T c Corresponding enthalpy value ; S4. Based on the cooling working fluid flow rate at the cooling working fluid inlet on the hot-end component of the aircraft. The saturation temperature T sat Corresponding enthalpy value and the enthalpy value corresponding to the working fluid inlet temperature Calculate the critical heat flux of the cooling working fluid in the pure liquid phase outflow. ; S5. Based on the upper temperature limit required by the hot-end component material. T max Determine the target temperature of the hot-end components after using the working fluid for cooling. T w Calculate the target temperature of the hot-end component. T w Corresponding wall enthalpy ; S6. Based on the cooling working fluid inlet flow rate. Enthalpy restoration h re Wall enthalpy Latent heat of phase transition of working fluid H vl enthalpy value enthalpy value Calculate the critical heat flux of the cooling working fluid in pure gas phase outflow. ; S7. Compare the surface heat flow of the hot-end components respectively. Q w Critical heat flux of pure liquid phase outflow of cooling working fluid Q 1. Critical heat flux of pure gas phase outflow Q 2. Size: If Q w <Q 1. If the outflow cooling medium is a pure liquid phase, then... Q 1 <Q w <Q 2. Then the outflow cooling medium is a gas-liquid mixture; if Q w >Q 2. Then the outflow cooling medium is pure gaseous phase; S8. Adjust the flow rate of the cooling working fluid at the inlet of the hot end component of the aircraft according to the cooling working fluid outflow state determined in S7.

[0005] Furthermore, the outflow conditions include the aircraft's angle of attack, Mach number, and flight altitude.

[0006] Furthermore, the cooling medium flow rate at the cooling medium inlet on the hot-end component of the aircraft is as follows: , in, C p It is the specific heat of air at constant pressure.

[0007] Furthermore, the critical heat flux of the pure liquid phase effluent of the cooling working fluid... .

[0008] Furthermore, the target temperature of the hot-end component after being cooled by the working fluid... .

[0009] Furthermore, the target temperature of the hot end component T w Corresponding wall enthalpy .

[0010] Furthermore, the critical heat flux of the pure gas phase effluent of the cooling working fluid is: , in, M air Indicates the molecular weight of air. M jet This indicates the molecular weight of the cooling working fluid. N α is the coefficient, and α is the exponent.

[0011] An evaluation system employing the above-mentioned rapid evaluation method for the effluent state of the evaporating cooling working fluid includes: The first module is used to perform aerodynamic and thermal numerical simulations of the external flow field of the hot-end components of the aircraft based on the external inflow conditions, and to obtain the surface heat flux of the hot-end components. Q w Surface pressure P w and recovery enthalpy h re According to the surface heat flow of the hot end component Q w and recovery enthalpy h re Determine the coolant inlet flow rate on the hot-end components of the aircraft. According to the surface pressure of the hot end component P w In addition to the thermodynamic properties of the cooling medium, the surface pressure of the cooling medium is calculated. P w The corresponding saturation temperature Tsat saturation temperature T sat Corresponding enthalpy value Latent heat of phase transition of working fluid H vl and working fluid inlet temperature T c Corresponding enthalpy value ; The second module is used to determine the cooling medium flow rate at the cooling medium inlet on the hot-end component of the aircraft. The saturation temperature T sat Corresponding enthalpy value and the enthalpy value corresponding to the working fluid inlet temperature Calculate the critical heat flux of the cooling working fluid in the pure liquid phase outflow. Based on the cooling working fluid inlet flow rate Enthalpy restoration h re Target temperature of hot end components T w Corresponding wall enthalpy Latent heat of phase transition of working fluid H vl enthalpy value enthalpy value Calculate the critical heat flux of the cooling working fluid in pure gas phase outflow. ; The third module is used to compare the surface heat flow of the hot-end components. Q w Critical heat flux of pure liquid phase outflow of cooling working fluid Q 1. Critical heat flux of pure gas phase outflow Q 2. Size: If Q w <Q 1. If the outflow cooling medium is a pure liquid phase, then... Q 1 <Q w <Q 2. Then the outflow cooling medium is a gas-liquid mixture; if Q w >Q 2. Then the outflow cooling medium is pure gaseous phase; The fourth module is used to adjust the inlet flow rate of the cooling working fluid on the hot-end components of the aircraft based on the cooling working fluid outflow state determined in the third module.

[0012] The advantages of this invention compared to the prior art are: (1) The method proposed in this invention can comprehensively evaluate the outflow state of the working fluid by taking into account the characteristic parameters of the sweating cooling hot end component, the aerodynamic thermal environment, and the working fluid flow rate. Based on the outflow state obtained from the evaluation, the phase state and flow boundary conditions of the cooling working fluid inlet on the hot end component of the aircraft can be obtained more accurately, thus solving the engineering problem of determining the design boundary conditions for the coupling of internal and external flow in sweating cooling.

[0013] (2) This invention is based on the derivation of the physical process of sweating and cooling, with a solid theoretical foundation, clear physical meaning, and high calculation efficiency. Attached Figure Description

[0014] Figure 1 This is a schematic diagram showing the outflow characteristics of the working fluid under different aerothermal environments and cooling fluid flow rates. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings.

[0016] Example like Figure 1 As shown, a schematic diagram of the working fluid outflow characteristics under different aerodynamic thermal environments and cooling working fluid flow rates is presented.

[0017] A rapid assessment method for the outflow state of a sweating cooling working fluid includes the following steps: S1. Based on the external flow conditions (including the aircraft's angle of attack, Mach number, and flight altitude), perform aerodynamic and thermal numerical simulations of the external flow field of the aircraft's hot-end components to obtain the surface heat flux of the hot-end components. Q w Surface pressure P w and recovery enthalpy h re .

[0018] S2, based on the surface heat flow obtained in step S1 Q w Enthalpy restoration h re Determine the coolant inlet flow rate on the hot-end components of the aircraft. working fluid inlet temperature T c Take 300K.

[0019]

[0020] in, C p The specific heat of air at constant pressure; S3. Based on the surface pressure obtained in step S1 P w In addition to the thermodynamic properties of the cooling medium, calculations were performed on the cooling medium under pressure.P w The corresponding saturation temperature T sat Enthalpy value corresponding to saturation temperature latent heat of phase transition of working fluid H vl Enthalpy value corresponding to the working fluid inlet temperature .

[0021] S4. Based on the cooling fluid flow rate in step S2 Enthalpy value corresponding to the saturation temperature in step S3 Enthalpy value corresponding to the inlet temperature of the working fluid Calculate the critical heat flux of the cooling working fluid in the pure liquid phase outflow. : ; S5. Based on the upper temperature limit required by the hot-end component material. T max Considering a 200K temperature margin, the target temperature for the hot-end components after using the working fluid for cooling is determined. T w =T max -200, calculate the wall enthalpy corresponding to the target temperature. ; S6. Based on the physical quantities obtained in steps S1 to S5, calculate the critical heat flux of the cooling working fluid in pure gas phase outflow. : , in, M air Indicates the molecular weight of air. M jet This represents the molecular weight of the cooling medium; N is a coefficient with a value of 0.72; α is an exponent with a value of 0.25. S7. Compare the surface heat flow of the hot-end components respectively. Q w Critical heat flux of pure liquid phase outflow of cooling working fluid Q 1. Critical heat flux of pure gas phase outflow Q 2. Size: If Q w <Q 1. If the outflow cooling medium is a pure liquid phase, then... Q 1 <Q w <Q 2. Then the outflow cooling medium is a gas-liquid mixture; if Q w >Q 2. Then the outflow cooling medium is pure gaseous phase; S8. Adjust the flow rate of the cooling working fluid at the inlet of the hot end component of the aircraft according to the cooling working fluid outflow state determined in step S7.

[0022] A rapid assessment system for the outflow status of a sweating cooling working fluid, characterized in that it includes: The first module is used to perform aerodynamic and thermal numerical simulations of the external flow field of the hot-end components of the aircraft based on the external inflow conditions, and to obtain the surface heat flux of the hot-end components. Q w Surface pressure P w and recovery enthalpy h re According to the surface heat flow of the hot end component Q w and recovery enthalpy h re Determine the coolant inlet flow rate on the hot-end components of the aircraft. According to the surface pressure of the hot end component P w In addition to the thermodynamic properties of the cooling medium, the surface pressure of the cooling medium is calculated. P w The corresponding saturation temperature T sat saturation temperature T sat Corresponding enthalpy value Latent heat of phase transition of working fluid H vl and working fluid inlet temperature T c Corresponding enthalpy value ; The second module is used to determine the cooling medium flow rate at the cooling medium inlet on the hot-end component of the aircraft. The saturation temperature T sat Corresponding enthalpy value and the enthalpy value corresponding to the working fluid inlet temperature Calculate the critical heat flux of the cooling working fluid in the pure liquid phase outflow. Based on the cooling working fluid inlet flow rate Enthalpy restoration h re Target temperature of hot end components T w Corresponding wall enthalpy Latent heat of phase transition of working fluid H vl enthalpy value enthalpy value Calculate the critical heat flux of the cooling working fluid in pure gas phase outflow. ; The third module is used to compare the surface heat flow of the hot-end components. Q w Critical heat flux of pure liquid phase outflow of cooling working fluid Q 1. Critical heat flux of pure gas phase outflow Q 2. Size: If Q w <Q 1. If the outflow cooling medium is a pure liquid phase, then... Q 1 <Q w <Q 2. Then the outflow cooling medium is a gas-liquid mixture; if Q w >Q 2. Then the outflow cooling medium is pure gaseous phase; The fourth module is used to adjust the inlet flow rate of the cooling working fluid on the hot-end components of the aircraft based on the cooling working fluid outflow state determined in the third module.

[0023] The method provided by this invention is not only applicable to the evaluation of the outflow state of the working fluid under the background of sweating and cooling, but also applicable to the evaluation of the outflow state under other scenarios involving the heating and phase change of the cooling working fluid.

[0024] The above embodiments are merely explanations of the present invention and should not be construed as limiting the present invention. Therefore, all implementation methods similar to the concept of the present invention are within the protection scope of the present invention.

[0025] The parts of this invention not described in detail are well-known to those skilled in the art.

Claims

1. A method for rapid evaluation of the outflow state of a sweating cooling working fluid, characterized in that, include: S1. Based on the external flow conditions, perform aerodynamic and thermal numerical simulation of the external flow field of the hot-end components of the aircraft to obtain the surface heat flux of the hot-end components. Q w Surface pressure P w and recovery enthalpy h re ; S2, based on the surface heat flow of the hot end component Q w and recovery enthalpy h re Determine the coolant inlet flow rate on the hot-end components of the aircraft. ; S3, based on the surface pressure of the hot end component P w In addition to the thermodynamic properties of the cooling medium, the surface pressure of the cooling medium is calculated. P w The corresponding saturation temperature T sat saturation temperature T sat Corresponding enthalpy value Latent heat of phase transition of working fluid H vl and working fluid inlet temperature T c Corresponding enthalpy value ; S4. Based on the cooling working fluid flow rate at the cooling working fluid inlet on the hot-end component of the aircraft. The saturation temperature T sat Corresponding enthalpy value and the enthalpy value corresponding to the working fluid inlet temperature Calculate the critical heat flux of the cooling working fluid in the pure liquid phase outflow. ; S5. Based on the upper temperature limit required by the hot-end component material. T max Determine the target temperature of the hot-end components after using the working fluid for cooling. T w Calculate the target temperature of the hot-end component. T w Corresponding wall enthalpy ; S6. Based on the cooling working fluid inlet flow rate. Enthalpy restoration h re Wall enthalpy Latent heat of phase transition of working fluid H vl enthalpy value enthalpy value Calculate the critical heat flux of the cooling working fluid in pure gas phase outflow. ; S7. Compare the surface heat flow of the hot-end components respectively. Q w Critical heat flux of pure liquid phase outflow of cooling working fluid Q 1. Critical heat flux of pure gas phase outflow Q 2. Size: If Q w <Q 1. If the outflow cooling medium is a pure liquid phase, then... Q 1 <Q w <Q 2. Then the outflow cooling medium is a gas-liquid mixture; if Q w >Q 2. Then the outflow cooling medium is a pure gas phase; S8. Adjust the flow rate of the cooling working fluid at the inlet of the hot end component of the aircraft according to the cooling working fluid outflow state determined in S7.

2. The method for rapid evaluation of the effluent state of a sweating cooling working fluid according to claim 1, characterized in that, The outflow conditions include the aircraft's angle of attack, Mach number, and flight altitude.

3. The method for rapid evaluation of the effluent state of a sweating cooling working fluid according to claim 2, characterized in that, Cooling fluid flow rate at the cooling fluid inlet on the hot-end component of the aircraft: ， in, C p It is the specific heat of air at constant pressure.

4. The method for rapid evaluation of the effluent state of a sweating cooling working fluid according to claim 3, characterized in that, The critical heat flux of the pure liquid phase effluent of the cooling working fluid .

5. The method for rapid evaluation of the effluent state of a sweating cooling working fluid according to claim 4, characterized in that, The target temperature of the hot-end component after being cooled by the working fluid .

6. The method for rapid evaluation of the effluent state of a sweating cooling working fluid according to claim 5, characterized in that, The target temperature of the hot end component T w Corresponding wall enthalpy .

7. The method for rapid evaluation of the effluent state of a sweating cooling working fluid according to claim 6, characterized in that, The critical heat flux of the cooling working fluid in pure gas phase outflow: ， in, M air Indicates the molecular weight of air. M jet This indicates the molecular weight of the cooling working fluid. N α is the coefficient, and α is the exponent.

8. A rapid evaluation system for the outflow state of a sweating cooling working fluid, characterized in that, include: The first module is used to perform aerodynamic and thermal numerical simulations of the external flow field of the hot-end components of the aircraft based on the external inflow conditions, and to obtain the surface heat flux of the hot-end components. Q w Surface pressure P w and recovery enthalpy h re According to the surface heat flow of the hot end component Q w and recovery enthalpy h re Determine the coolant inlet flow rate on the hot-end components of the aircraft. ; According to the surface pressure of the hot end component P w In addition to the thermodynamic properties of the cooling medium, the surface pressure of the cooling medium is calculated. P w The corresponding saturation temperature T sat saturation temperature T sat Corresponding enthalpy value Latent heat of phase transition of working fluid H vl and working fluid inlet temperature T c Corresponding enthalpy value ; The second module is used to determine the cooling medium flow rate at the cooling medium inlet on the hot-end component of the aircraft. The saturation temperature T sat Corresponding enthalpy value and the enthalpy value corresponding to the working fluid inlet temperature Calculate the critical heat flux of the cooling working fluid in the pure liquid phase outflow. Based on the cooling working fluid inlet flow rate Enthalpy restoration h re Target temperature of hot end components T w Corresponding wall enthalpy Latent heat of phase transition of working fluid H vl enthalpy value enthalpy value Calculate the critical heat flux of the cooling working fluid in pure gas phase outflow. ; The third module is used to compare the surface heat flow of the hot-end components. Q w Critical heat flux of pure liquid phase outflow of cooling working fluid Q 1. Critical heat flux of pure gas phase outflow Q 2. Size: If Q w <Q 1. If the outflow cooling medium is a pure liquid phase, then... Q 1 <Q w <Q 2. Then the outflow cooling medium is a gas-liquid mixture; if Q w >Q 2. Then the outflow cooling medium is a pure gas phase; The fourth module is used to adjust the inlet flow rate of the cooling working fluid on the hot-end components of the aircraft based on the cooling working fluid outflow state determined in the third module.

9. The rapid evaluation system for the effluent state of a sweating cooling working fluid according to claim 8, characterized in that, Cooling fluid flow rate at the cooling fluid inlet on the hot-end component of the aircraft: ， in, C p It is the specific heat of air at constant pressure.

10. A rapid evaluation system for the effluent state of a sweating cooling working fluid according to claim 9, characterized in that, The critical heat flux of the cooling working fluid in pure gas phase outflow: ， Among them, the target temperature of the hot end component T w Corresponding wall enthalpy The target temperature of the hot-end component after cooling with working fluid ; M air Indicates the molecular weight of air. M jet This indicates the molecular weight of the cooling working fluid. N α is the coefficient, and α is the exponent.

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