A sweating cooling material trans-phase state wide working condition thermal mass transport characteristic property measurement platform and method

Abstract

The application discloses a kind of sweating cooling material transphase state wide working condition heat mass transport characteristic property measurement platform and method, and measurement platform is composed of working medium system, container system and measurement and control system.Wherein, working medium system can be in parallel to supply single-phase or multi-phase mixed working medium, control working medium flow, thermodynamic parameter such as temperature;Container system has clamping, support, rectification and the like functions, can maintain the closed, uniform working medium flow passage required by measurement, and provides installation site for measurement and control instrument, probe;Measurement and control system is used to control various valve bodies in platform, heater and the like active components, collects, stores thermodynamic data.The present application can carry out synchronous test to the seepage, heat transfer characteristics of sweating cooling material, simultaneously obtain viscidity, inertial resistance coefficient and body convection heat transfer coefficient and the like data, and can carry out cold state, hot state wide working condition range test, carry out transflow state, transphase state experiment, facilitate to explore the variation law of two-phase seepage, diffusion and heat exchange process related physical property parameters in material.

Description

Technical Field

[0001] This invention belongs to the field of thermal protection material property testing technology, and specifically relates to a measurement platform and method for the thermal and mass transport characteristics of sweating cooling materials across phases and operating conditions. Background Technology

[0002] Sweating cooling is an active thermal protection technology used to address the extreme thermal loads encountered during the cruise of hypersonic vehicles. Its principle lies in the fact that as the working fluid passes through the surface structure of the aircraft, it carries away some heat through convection, thus providing a cooling effect. Subsequently, the working fluid permeates out of the aircraft surface and forms a gas film, producing an insulating effect. Therefore, sweating cooling materials need to contain a large number of porous structures to provide pathways for the permeation of the cooling working fluid. Common materials include metal-based materials such as metal mesh and sintered metals, as well as ceramic-based composite materials such as C / C and C / SiC. Furthermore, with the maturity of technologies such as additive manufacturing, some porous materials with complex topologies such as triple-period minimal surfaces (TPMS) are being applied to sweating cooling. When designing sweating cooling systems using the above materials, the cooling effect is generally evaluated through numerical or experimental methods, followed by structural optimization. During this process, it is necessary to clarify the internal heat and mass transport properties of the material, such as permeability and convective heat transfer coefficient, and to obtain the structure-property relationship between the material's pore structure and permeation and heat transfer characteristics.

[0003] As aircraft speeds increase, the thermal environment they face becomes increasingly harsh. Perspiration cooling is evolving from a single-phase gaseous state to a gas-liquid phase change process, utilizing the latent heat of vaporization to achieve superior heat dissipation. Related studies have confirmed the effectiveness of phase change perspiration cooling in improving cooling efficiency; however, these studies typically use single-phase permeability and convective heat transfer coefficients in numerical simulations, failing to fully consider the impact of the gas-liquid phase change process on these parameters. Measurements of the percolation heat transfer characteristics of perspiration cooling materials are also limited to cold-state, single-phase working fluids, with limited experimental research on hot-state, multiphase working fluids. Therefore, there is an urgent need for a measurement platform and testing method for the thermal and mass transport characteristics of perspiration cooling materials across phase states and operating conditions. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the present invention aims to provide a measurement platform and method for the thermal and mass transport characteristics of sweating cooling materials under a wide range of operating conditions and in a cross-phase state, so as to solve the problem that the prior art cannot measure the percolation heat transfer characteristic parameters of sweating cooling materials under hot or multiphase working fluid conditions.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A measurement platform for the thermal and mass transport characteristics of sweating cooling materials across phases and operating conditions includes a working fluid system, a container system, and a measurement and control system.

[0007] The working fluid system supplies one or more of the working fluids in the gas phase, liquid phase and vapor phase to the container system, and independently controls the flow rate of each phase;

[0008] The container system includes a sample container, which includes an inlet section and an outlet section. A clamp support and temperature control platform with a central hole is provided on the side of the outlet section near the inlet section. The sample to be tested is fixed in its circumference by a sample clamp. The sample to be tested is located between the clamp support and temperature control platform and the inlet section, so that the working fluid flows along the path of the inlet section, the sample to be tested, the central hole and the outlet section.

[0009] The measurement and control system is used to obtain the average temperature of the sample under test and the pressure, temperature and flow rate of the working fluid before and after it, and to solve the inverse problem of the characteristic equation of the porous permeation heat transfer process to obtain the characteristic physical properties of heat and mass transport.

[0010] In one embodiment, the working fluid system includes a gas phase working fluid subsystem, a liquid phase working fluid subsystem, and a vapor phase working fluid subsystem. Each subsystem is equipped with a mass flow controller and a pressure regulating valve. Each subsystem is connected to a multi-channel adjustable mixing valve. The multi-channel adjustable mixing valve has a four-way structure. After mixing the input of each phase, a stainless steel pipe is led out and connected to the inlet compartment.

[0011] In one embodiment, a controllable heating and insulation device is installed on the outside of the stainless steel pipe. This device measures the temperature by thermocouples on the outer wall of the stainless steel pipe, heats and insulates the pipe by winding glass fiber heating tape, and leads out a control line plug to an integrated control console.

[0012] In one embodiment, along the flow direction of the working fluid, the inlet section contains a diffusion rectification section and a contraction rectification section in sequence. The inlet section is provided with an inlet section pressure tap, and the outlet section is provided with an outlet section pressure tap and a liquid discharge and exhaust pipe.

[0013] In one embodiment, the shrink rectifier section, the sample to be tested, and the sample fixture are combined to form a sample tooling assembly, which is mounted on the fixture support and temperature control platform via the sample fixture.

[0014] In one embodiment, the sample container is provided with a multi-layer sealing structure, including: an inlet end face seal arranged between the inflow end face of the sample working medium and the shrinkage rectifier section, an outlet end face seal arranged between the outflow end face of the sample working medium and the sample fixture, a circumferential seal arranged between the circumferential side of the sample and the sample fixture, and a tooling fitting seal arranged between the fixture support and the temperature control platform and the sample fixture.

[0015] In one embodiment, the sample to be tested is circumferentially surrounded by an elastomer, and the sample clamp and the shrinkage rectifier section both compress the elastomer from both sides through a flange structure, causing it to expand and fill the gap between the sample to be tested and the sample clamp, thus providing the circumferential seal.

[0016] In one embodiment, the clamp support and temperature control platform is equipped with a controllable preheating device on the exit section side. The device uses a heat insulation cover and cover fastening screws to keep the heating band tightly attached to the clamp support and temperature control platform, and leads out an insulated and sealed wiring plug to the integrated control console.

[0017] In one embodiment, the sample container is equipped with four sets of thermal resistors: first, one set located in the inlet section adjacent to the sample to be tested; second, one set located on the surface of the sample to be tested on the side of the inlet section; third, one set located in the outlet section adjacent to the sample to be tested; and fourth, one set located on the surface of the sample to be tested on the side of the outlet section.

[0018] The second objective of this invention is to provide a method for measuring the characteristic heat and mass transport properties of sweating cooling materials across a wide operating condition and in a transphase state. This method is based on the measurement platform for the characteristic heat and mass transport properties of sweating cooling materials across a wide operating condition and in a transphase state described in the first objective, and includes the following steps:

[0019] First, obtain the average temperature of the sample to be tested and the time series of changes in pressure, temperature and flow rate of the working fluid before and after it;

[0020] Subsequently, the inverse problem of the characteristic equation for the porous permeation heat transfer process was solved using the "hypothesis-forward modeling-correction" method:

[0021] The equations for the characteristic properties of internal seepage in the material are as follows:

[0022]

[0023] In the formula, D is the matrix of viscous drag coefficients to be determined, and C is the matrix of inertial drag coefficients to be determined; t is time. Let p be the fluid velocity and p be the fluid pressure. For stress tensor, Let ρ be the acceleration due to gravity. f For fluid density, μ f For fluid dynamic viscosity;

[0024] The equations for the heat transfer characteristics within the material are as follows:

[0025]

[0026] In the formula, h sf Let be the volumetric convective heat transfer coefficient to be determined; t be time. Let E be the fluid velocity, p be the fluid pressure, and E be the fluid velocity. fT is the total fluid energy. f T s Temperatures of fluid and solid, respectively, h i J is the enthalpy value of component i. i Let i be the diffusion flux of component i. For shear stress, ρ f k is the fluid density. f,eff k s,eff These are the equivalent thermal conductivity of the fluid and solid, respectively, c p,s For the specific heat capacity of a solid at constant pressure, α sf q represents the specific surface area of ​​the material. boil For phase change heat transfer, S f S s These are the internal heat source terms for fluids and solids, respectively.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] 1. This invention provides a measurement platform and testing method for the thermal and mass transport characteristics of sweating cooling materials across phases and operating conditions. It can realize the simultaneous testing of the permeation characteristics and heat transfer characteristics of sweating cooling materials. The results of a single round of experiments include physical property parameters such as viscous drag coefficient, inertial drag coefficient and volume convective heat transfer coefficient, effectively saving testing time.

[0029] 2. The present invention provides a measurement platform and testing method for the characteristic heat and mass transport properties of sweating cooling materials under wide operating conditions and in a cross-phase state. It can study the seepage, diffusion and heat transfer laws of multiphase mixed working fluids inside sweating cooling materials and obtain the characteristic heat and mass transport parameters of cross-phase state, thus making up for the shortcomings of existing studies that only focus on the seepage and heat transfer of single-phase working fluids inside sweating cooling materials.

[0030] 3. The present invention provides a measurement platform and testing method for the thermal and mass transport characteristics of sweating cooling materials across phase states and operating conditions. It can preheat the working fluid and sample to a maximum temperature of 500K, and can carry out hot percolation heat transfer experiments on sweating cooling materials. The operating parameters are closer to the service conditions, and the experimental results are more practical for the pre-research of phase change sweating cooling technology. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the transphase wide-condition thermal and mass transport characteristic property measurement platform for the sweating cooling material of the present invention.

[0032] Figure 2 This is a schematic diagram of a 1 / 4 cross-sectional structure of the measurement platform container system.

[0033] Figure 3 This is a schematic diagram of the sample tooling assembly.

[0034] Figure 4This is a schematic diagram of the fixture support and temperature control platform within the measurement platform container system.

[0035] Figure 5 This is a cross-sectional schematic diagram of the stainless steel pipeline and its external controllable heating and insulation device.

[0036] Figure 6 The diagram shows the results of testing mesoporous and macroporous materials using the platform of this invention; where (a) is the curve of pressure gradient as a function of apparent velocity, and (b) is the dependence of characteristic properties on pressure gradient. Detailed Implementation

[0037] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings and examples.

[0038] like Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, this invention first provides a transphase, wide-condition measurement platform for the thermal and mass transport characteristics of sweating cooling materials, mainly comprising three parts: a working fluid system, a container system, and a measurement and control system. This invention is applicable to various sweating cooling materials with mesoporous or microporous structures, such as metal-based materials like metal mesh and sintered metals, and ceramic-based composite materials like C / C and C / SiC.

[0039] The function of the working fluid system is to supply working fluid to the container system. In this invention, the working fluid supplied to the container system according to the test requirements is one or more of the gas phase, liquid phase and vapor phase working fluid, and the flow rate of each phase can be controlled independently.

[0040] The container system mainly includes a sample container 15, which comprises an inlet section 39 and an outlet section 40. A clamp support and temperature control platform 42 with a central hole is disposed between the inlet section 39 and the outlet section 40, the central hole being positioned along the flow direction of the working fluid. The sample to be tested 28 is fixed circumferentially by a sample clamp 43, and the sample to be tested 28 is located between the clamp support and temperature control platform 42 and the inlet section 39, allowing the working fluid to flow along the path of the inlet section 39, the sample to be tested 28, the central hole, and the outlet section 40.

[0041] The measurement and control system is used to obtain the average temperature of the sample 28 to be tested and the pressure, temperature and flow rate of the working fluid before and after it, and to solve the inverse problem of the characteristic equation of the porous permeation heat transfer process to obtain the characteristic physical properties of heat and mass transport.

[0042] Based on the above structure, this invention integrates multiple functions through a container system, enabling simultaneous testing of the permeation and heat transfer characteristics of sweating cooling materials. It also acquires data such as viscous drag coefficient, inertial drag coefficient, and volumetric convective heat transfer coefficient, effectively improving testing efficiency. Furthermore, through modular design, this invention achieves mixed-phase working fluid supply, allowing for testing across a wide range of operating conditions, including cold and hot states, and conducting cross-flow and cross-phase experiments. This facilitates the investigation of the changes in relevant physical properties during two-phase permeation, diffusion, and heat transfer processes within the material.

[0043] In an embodiment of the present invention, reference is made to... Figure 1 As shown, the working fluid system adopts a modular design, comprising three sets of working fluid supply modules: liquid, gas, and humid steam. These modules can be connected in parallel to supply single-phase or multi-phase mixed working fluids. Each module can be individually installed and disassembled, and its flow rate, pressure, temperature, and other thermodynamic parameters can be controlled separately. For example, the working fluid system includes a gas phase working fluid subsystem, a liquid phase working fluid subsystem, and a vapor phase working fluid subsystem. Each subsystem is equipped with a mass flow controller and a pressure regulating valve. Each subsystem is connected to a multi-channel adjustable mixing valve 10, which has a four-way structure. After mixing the input phases, a stainless steel pipe 50 is led out and connected to the inlet section 39 to supply the working fluid to the container system.

[0044] Specifically, the gas-phase working propellant system includes a gas mass flow controller 1, a gas pressure regulating valve 2, and a gas generating device 3. In one embodiment of the invention, the gas generating device 3 is a gas cylinder equipped with a pressure reducing valve. The liquid-phase working propellant system includes a liquid mass flow controller 4, a liquid pressure regulating valve 5, and a liquid generating device 6. In one embodiment of the invention, the liquid generating device 6 is equipped with a water tank and a gear pump. The vapor-phase working propellant system includes a vapor mass flow controller 7, a vapor pressure regulating valve 8, and a vapor generating device 9.

[0045] In this embodiment, the gas generator 3, gas pressure regulating valve 2, and gas mass flow controller 1 are connected in series using connectors and connected to the multi-channel adjustable mixing valve 10 to input the gas phase working fluid. The liquid generator 6, liquid pressure regulating valve 5, and liquid mass flow controller 4 are connected in series using connectors and connected to the multi-channel adjustable mixing valve 10 to input the liquid phase working fluid. The steam generator 9, steam pressure regulating valve 8, and steam mass flow controller 7 are connected in series using connectors and connected to the multi-channel adjustable mixing valve 10 to input the steam phase working fluid. In one embodiment of the invention, the connectors are stainless steel pipes and compression fittings that are straight through. The multi-channel adjustable mixing valve 10 has a four-way structure. After mixing the multiphase input, a stainless steel pipe 50 is led out to supply a multi-component transphase working fluid to the sample container 15. An inlet mass flow meter 11 is installed on the stainless steel pipe 50.

[0046] In an embodiment of the present invention, the container system is a test section of a measurement platform, possessing functions such as clamping, support, and rectification. It can maintain the required closed and uniform flow path of the working fluid for measurement and provides mounting points for various measurement and control instruments and probes, facilitating functional integration and enabling simultaneous measurement of multiple parameters. (Reference) Figure 1 and Figure 2 As shown, it mainly includes a sample container 15, which has a stainless steel shell 41. Functionally, its interior mainly includes an inlet section 39 and an outlet section 40. The inlet section 39 is equipped with an inlet section flange 25 at its end, which is connected to the working medium inlet pipe 24 for connecting to the stainless steel pipe 50 to introduce the working medium. Along the flow direction of the working medium, the interior of the inlet section 39 consists of a diffusion rectification section 26 and a contraction rectification section 27, and the inlet section 39 is provided with an inlet section pressure tap 29. The outlet section 40 is equipped with an outlet section flange 32 at its end, which is connected to the working medium outlet pipe 34, and also leads out a measurement and control channel with a measurement and control flange 33. The outlet section 40 is provided with an outlet section pressure tap 30 and a drain and vent pipe 31. The sample container 15, through pre-designed interfaces such as the inlet section pressure tap 29, the outlet section pressure tap 30, and the control flange 33, provides mounting points and signal line paths for instruments such as pressure and temperature measuring elements, enabling the measurement platform to simultaneously test seepage and heat transfer characteristics. The entire sample container 15 can be mounted and supported by the container system bracket 38.

[0047] Through the aforementioned diffusion rectifying section 26 and contraction rectifying section 27, the present invention possesses a dual rectification structure. Specifically, the diffusion rectifying section 26 is connected to the end of the working fluid inlet pipe 24. The non-uniformity caused by the jet is eliminated when the fluid flows through the diffusion rectifying section 26, and then it enters the contraction rectifying section 27. When the working fluid flows through this section, the cross-sectional area gradually decreases, the streamline is forced to tend to be straight, and the flow field quality is improved.

[0048] In an embodiment of the present invention, reference is made to... Figure 2 and Figure 3 The shrink rectifier section 27, the sample to be tested 28 and the sample clamp 43 are combined to form a sample tooling fitting. The sample tooling fitting is installed on the clamp support and temperature control platform 42 by the sample clamp 43. As an elastic component of the measurement platform, the operator can easily adapt to material samples of different sizes and shapes by replacing the sample clamp 43.

[0049] In an embodiment of the present invention, reference is made to... Figure 3To ensure the airtightness of the working fluid flow area, the sample container 15 is equipped with multiple sealing structures, including: an inlet end face seal 36 arranged between the working fluid inflow end face of the sample 28 and the contraction and rectification section 27; an outlet end face seal 37 arranged between the working fluid outflow end face of the sample 28 and the sample clamp 43; a circumferential seal 44 arranged between the circumferential side of the sample 28 and the sample clamp 43; and a tooling fitting seal 35 arranged between the clamp support and temperature control platform 42 and the sample clamp 43. In one embodiment of the present invention, the above seals may be fluororubber O-rings.

[0050] Furthermore, the circumferential seal 44 can be formed by: an elastomer being sleeved around the circumference of the sample to be tested 28. In one embodiment of the present invention, the elastomer is a rubber ring. The sample clamp 43 and the shrinkage rectification section 27 both press the two sides of the elastomer (i.e., the two sides along the flow direction of the working fluid) against each other through the flange structure 53, so that it expands and fills the gap between the sample to be tested 28 and the sample clamp 43, thus providing the circumferential seal 44.

[0051] In an embodiment of the invention, the clamp support and temperature control platform 42 is equipped with a controllable preheating device on one side of the exit section 40 to raise the temperature of the clamp and sample, prevent vapor phase condensation, or provide a higher initial temperature for hot-state experiments. (Reference) Figure 4 The device uses a heat insulation cover plate 422 and cover plate fastening screws 423 to make the heating band 421 fit tightly against the clamp support and temperature control platform 42, and leads out an insulated and sealed wiring plug 424 to connect to the integrated control console 23.

[0052] In this invention, the measurement and control system is used to control various active components such as valves and heaters in the platform, provide suitable working conditions for the sensors, and collect and store thermodynamic data such as pressure, flow rate, and temperature. It mainly includes an inlet mass flow meter 11, an inlet compartment pressure transmitter 14, an outlet compartment pressure transmitter 16, a cooler 17, an outlet mass flow meter 18, a resistance temperature detector 45, a data acquisition instrument 19, a host computer 20, an analog signal bus 21, a digital signal cable 22, and an integrated control console 23.

[0053] refer to Figure 2 In one embodiment of the present invention, in order to obtain the temperature of the sample 28 to be tested and the corresponding working fluid from all angles, the present invention arranges a total of four sets of thermal resistors 45 inside the sample container 15. First, they are arranged in the inlet section 39 adjacent to the sample 28 to monitor the temperature of the working fluid before the sample. Second, they are arranged on the surface of the sample 28 to be tested on the side of the inlet section 39 to monitor the temperature of the inlet side of the sample 28. Third, they are arranged in the outlet section 40 adjacent to the sample 28. Fourth, they are arranged on the surface of the sample 28 to be tested on the side of the outlet section 40 to monitor the temperature of the outlet side of the sample 28.

[0054] refer to Figure 5In one embodiment of the present invention, in order to preheat and increase the temperature of the input working fluid, a controllable heating and heat preservation device is installed on the outside of the stainless steel pipe 50 that flows in front of the working fluid input sample container 15. The device measures the temperature by thermocouple 501 on the outer wall of the stainless steel pipe 50, and heats and preserves the temperature by the wound glass fiber heating tape 502. The control line plug 503 is led out to connect to the integrated control console 23.

[0055] This invention provides a measurement platform for the thermal and mass transport characteristics of diaphoretic cooling materials across a wide operating condition and a method for testing the viscous drag coefficient, inertial drag coefficient, and bulk convective heat transfer coefficient of diaphoretic cooling materials, comprising the following steps:

[0056] First, the average temperature of the sample 28 and the time series of changes in pressure, temperature, and flow rate of the working fluid before and after it were obtained. The complete experimental procedure can be described as follows:

[0057] 1) Exhaust

[0058] Vacuum is drawn through the drain and exhaust pipe 31;

[0059] 2) Working fluid temperature control

[0060] Use the integrated control console 23 to set the working fluid temperature, fixture and sample preheating temperature. After the experimental system is preheated and the temperature stabilizes at the set value, start the working fluid supply. Observe the working fluid temperature in front of the sample through the host computer 20. Adjust the working fluid temperature setting value through the integrated control console 23 to stabilize the working fluid temperature in front of the sample at the set value.

[0061] 3) Working fluid pressure control

[0062] The pressure in the inlet compartment is observed through the host computer 20. The working medium pressure is adjusted by using the gas pressure regulating valve 2, the liquid pressure regulating valve 5 and the steam pressure regulating valve 8 to make it rise slowly and uniformly.

[0063] 4) Data Acquisition

[0064] The data acquisition instrument 19 and the host computer 20 continuously read and record the data from the inlet section pressure transmitter 14 and the outlet section pressure transmitter 16. The two sets of pressure data are, in the direction of flow, the pressure before the sample p. u and sample post-pressure p d The data from the outlet mass flow meter 18 is continuously read and recorded by the data acquisition instrument 19 and the host computer 20. This data is used as the working fluid flow rate q through the sample. V,n The data acquisition instrument 19 and the host computer 20 continuously read and recorded the data of the thermal resistance 45. The four sets of temperature data, in the direction of flow, are the working fluid temperature T before the sample. f,u Sample inlet temperature T p,u Sample outlet temperature T p,d and the working fluid temperature T after the samplef,d .

[0065] Subsequently, based on the transient measurements of the aforementioned instruments, the average temperature of the sample 28 under test and the time series of pressure, temperature, and flow rate changes of the working fluid before and after it were calculated. Using the "hypothesis-forward modeling-correction" method, the characteristic equation of the porous permeation heat transfer process was solved inversely to obtain the viscous drag coefficient, inertial drag coefficient, and volumetric convective heat transfer coefficient of the working fluid permeating heat transfer within the sample 28 under test. The specific implementation method is as follows:

[0066] 1) For material internal seepage characteristics such as viscous resistance coefficient and inertial resistance coefficient.

[0067] (A) Based on the measured flow rate of the working fluid flowing through the sample, the flow velocity of the working fluid inside the sweating cooling material is calculated. The first step is to convert the mass flow meter measurement into a volumetric flow rate value under the test environment temperature and pressure. The conversion method is as follows:

[0068]

[0069] In the formula, ρ and q represent density and volumetric flow rate, respectively, while the subscripts r and n represent the actual measurement environment and the calibration environment of the mass flow meter, respectively. In one embodiment of the present invention, this is the standard state (1 atm, 273 K). The second step is to calculate the apparent flow velocity inside the sweating cooling material based on the calculated volumetric flow rate value. The calculation method is as follows:

[0070]

[0071] In the formula, d represents the equivalent flow diameter of the test section.

[0072] (B) Given the working fluid flow rate (u) and the pressure after the sample (p) d Using information such as ) as boundary and initial conditions, and assuming a set of viscous drag coefficients and inertial drag coefficients, the finite volume method is used to perform forward modeling of the seepage characteristic differential equation shown below, obtaining the forward modeling result of the pressure in front of the sample (p). u,a ):

[0073]

[0074] In the formula, D is the matrix of viscous drag coefficients to be determined, and C is the matrix of inertial drag coefficients to be determined; t is time. Let p be the fluid velocity and p be the fluid pressure. For stress tensor, Let ρ be the acceleration due to gravity. f For fluid density, μ f For fluid dynamic viscosity;

[0075] (C) The forward modeling results of the pressure before the sample (p)u,a ) and the measured value of the sample inlet pressure (p) u By comparison, the assumed values ​​of the viscous drag coefficient and the inertial drag coefficient are corrected based on the comparison results.

[0076] (D) Repeat step (B) until the forward calculation result of the post-sample pressure is obtained (p u,a The measured pressure (p) after convergence to the sample u ).

[0077] 2) For the internal heat transfer characteristics of materials, such as the volumetric convection heat transfer coefficient.

[0078] (A) Calculate the average temperature of the sample and fluid based on the measured values ​​of the sample inlet and outlet temperatures. The calculation method is as follows:

[0079]

[0080] In the formula, T p,m T represents the average temperature of the sample. f,m The average temperature of the fluid.

[0081] (B) Given the known working fluid flow rate (u) and the working fluid temperature before the sample (T) f,u Using information such as boundary conditions and initial conditions, and assuming a volumetric convective heat transfer coefficient, the finite volume method is used to perform forward modeling of the heat transfer characteristic differential equation shown below, obtaining the forward modeling result of the working fluid temperature after the sample (T). fa,d ):

[0082]

[0083] In the formula, h sf Let be the volumetric convective heat transfer coefficient to be determined; t be time. Let E be the fluid velocity, p be the fluid pressure, and E be the fluid velocity. f T is the total fluid energy. f T s Temperatures of fluid and solid, respectively, h i J is the enthalpy value of component i. i Let i be the diffusion flux of component i. For shear stress, ρ f k is the fluid density. f,eff k s,eff These are the equivalent thermal conductivity of the fluid and solid, respectively, c p,s For the specific heat capacity of a solid at constant pressure, α sf q represents the specific surface area of ​​the material. boil For phase change heat transfer, S f S s These are the internal heat source terms for fluids and solids, respectively.

[0084] (C) The forward modeling results of the working fluid temperature after the sample (T) fa,d ) and the measured value of the working fluid temperature after the sample (T) f,d By comparison, the assumed value of the convective heat transfer coefficient of the body is corrected based on the comparison results;

[0085] (D) Repeat step (B) until the forward calculation result of the working fluid temperature after the sample is obtained (T). fa,d The measured value of the working fluid temperature after convergence to the sample (T) f,d ).

[0086] If the internal thermal resistance of the material is ignored, the following formula is used to fit the curve of the average temperature of the sample increasing with time to obtain the volumetric convective heat transfer coefficient of the working fluid permeating heat transfer in the sweating cooling material:

[0087]

[0088] In the formula, T p,m0 The initial average temperature of the sample is given by the subscript p, which indicates the sweating cooling material.

[0089] In one embodiment of the present invention, the parameter correction process can be accelerated by using a suitable algorithm, including but not limited to genetic algorithms, neural networks, etc.

[0090] The transphase wide-condition thermal and mass transport characteristic property measurement platform for the sweating cooling material was used to test mesoscopic and macroscopic porous materials, and obtained the following results. Figure 6 The pressure gradient curve shown in (a) as a function of apparent velocity agrees well with the Kozeny-Carman theoretical prediction. Further data processing using the transphase wide-condition thermal and mass transport characteristic property testing method for the described sweating cooling material can yield... Figure 6 The variation of characteristic properties with pressure gradient shown in (b) has a small error with the numerical simulation results using the same physical model and boundary parameters.

[0091] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art can easily make changes or modifications within the scope of the present invention, and such changes or modifications should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A measurement platform for the thermal and mass transport characteristics of sweating cooling materials across phases and operating conditions, characterized in that, This includes the working fluid system, container system, and measurement and control system; The working fluid system supplies gaseous, liquid, and vapor phase working fluids to the container system, and independently controls the flow rate of each phase; The container system includes a sample container (15), which includes an inlet section (39) and an outlet section (40). A clamp support and temperature control platform (42) with a central hole is provided on the side of the outlet section (40) near the inlet section (39). The sample to be tested (28) is fixed in its circumference by a sample clamp (43). The sample to be tested (28) is located between the clamp support and temperature control platform (42) and the inlet section (39), so that the working fluid flows along the path of the inlet section (39), the sample to be tested (28), the central hole and the outlet section (40). The measurement and control system is used to obtain the average temperature of the sample (28) to be tested and the pressure, temperature and flow rate of the working fluid before and after it, and to solve the inverse problem of the characteristic equation of the porous permeation heat transfer process to obtain the characteristic physical properties of heat and mass transport. The working fluid system includes a gas phase working fluid subsystem, a liquid phase working fluid subsystem and a vapor phase working fluid subsystem. Each subsystem is equipped with a mass flow controller and a pressure regulating valve. Each subsystem is connected to a multi-channel adjustable mixing valve (10). The multi-channel adjustable mixing valve (10) has a four-way structure. After mixing the input of each phase, a stainless steel pipe (50) is led out and connected to the inlet compartment (39).

2. The transphase wide-condition thermal and mass transport characteristic property measurement platform for sweating cooling materials according to claim 1, characterized in that, The stainless steel tube (50) is equipped with a controllable heating and heat preservation device. The device measures the temperature by using a thermocouple (501) on the outer wall of the stainless steel tube (50), and heats and preserves the temperature by using a wound glass fiber heating tape (502). The control line plug (503) is led out to connect to the integrated control console (23).

3. The transphase wide-condition thermal and mass transport characteristic property measurement platform for sweating cooling materials according to claim 1, characterized in that, Along the flow direction of the working fluid, the interior of the inlet section (39) consists of a diffusion rectification section (26) and a contraction rectification section (27). The inlet section (39) is provided with an inlet section pressure tap (29), and the outlet section (40) is provided with an outlet section pressure tap (30) and a liquid discharge and exhaust pipe (31).

4. The transphase wide-condition thermal and mass transport characteristic property measurement platform for sweating cooling materials according to claim 3, characterized in that, The shrinking rectifier section (27), the sample to be tested (28), and the sample fixture (43) are combined to form a sample tooling fitting, which is installed on the fixture support and temperature control platform (42) by the sample fixture (43).

5. The transphase wide-condition thermal and mass transport characteristic property measurement platform for sweating cooling materials according to claim 3, characterized in that, The sample container (15) is provided with multiple sealing structures, including: an inlet end face seal (36) arranged between the working fluid inflow end face of the sample to be tested (28) and the shrinkage rectification section (27); an outlet end face seal (37) arranged between the working fluid outflow end face of the sample to be tested (28) and the sample clamp (43); a circumferential seal (44) arranged between the circumferential side of the sample to be tested (28) and the sample clamp (43); and a tooling fitting seal (35) arranged between the clamp support and temperature control platform (42) and the sample clamp (43).

6. The transphase wide-condition thermal and mass transport characteristic property measurement platform for sweating cooling materials according to claim 5, characterized in that, The test sample (28) is surrounded by an elastic body. The sample clamp (43) and the shrinkage rectification section (27) both squeeze the two sides of the elastic body in opposite directions through the flange structure (53), so that it expands and fills the gap between the test sample (28) and the sample clamp (43), providing the circumferential seal (44).

7. The transphase wide-condition thermal and mass transport characteristic property measurement platform for sweating cooling materials according to claim 1, characterized in that, The clamp support and temperature control platform (42) is equipped with a controllable preheating device on the side of the exit section (40). The device uses a heat insulation cover plate (422) and cover plate fastening screws (423) to make the heating belt (421) stick tightly to the clamp support and temperature control platform (42), and leads out an insulated and sealed wiring plug (424) to connect to the integrated control console (23).

8. The transphase wide-condition thermal and mass transport characteristic property measurement platform for sweating cooling materials according to claim 1, characterized in that, The sample container (15) is equipped with a total of 4 sets of thermal resistors (45). First, they are arranged in the inlet section (39) next to the sample (28) to be tested; second, they are arranged on the surface of the sample (28) to be tested on the side of the inlet section (39); and third, they are arranged in the outlet section (40) next to the sample (28) to be tested. Fourth, the sample (28) to be tested is placed on the surface of the export compartment (40).

9. A method for measuring the characteristic heat and mass transport properties of sweating cooling materials across a wide operating condition and in a transphase state, implemented based on the measurement platform for the characteristic heat and mass transport properties of sweating cooling materials across a wide operating condition and in a transphase state as described in any one of claims 1-8, characterized in that, Includes the following steps: First, the average temperature of the sample to be tested (28) and the time series of changes in pressure, temperature and flow rate of the working fluid before and after it are obtained; Subsequently, the inverse problem of the characteristic equation for the porous permeation heat transfer process was solved using the "hypothesis-forward modeling-correction" method: The equations for the characteristic properties of internal seepage in the material are as follows: In the formula, D Let be the matrix of viscous drag coefficients to be determined. C Let be the matrix of inertial drag coefficients to be determined; t For time, For fluid velocity, p For fluid pressure, For stress tensor, It is the acceleration due to gravity. ρ f For fluid density, μ f For fluid dynamic viscosity; The equations for the heat transfer characteristics within the material are as follows: In the formula, h sf Let be the volumetric convective heat transfer coefficient to be determined; t For time, For fluid velocity, p For fluid pressure, E f For total fluid energy, T f , T s They are fluid and solid temperatures, respectively. h i Let i be the enthalpy value of component i. J i Let i be the diffusion flux of component i. For shear stress, ρ f For fluid density, k f ,eff , k s ,eff These are the equivalent thermal conductivity coefficients for fluids and solids, respectively. c p,s The specific heat capacity at constant pressure of a solid. α sf The specific surface area of ​​the material. q boil For phase change heat transfer, S f , S s These are the internal heat source terms for fluids and solids, respectively.

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