Rapidly-assembled liquid-cooled camouflage clothes based on flow-heat topological optimization

Abstract

The invention discloses a fast assembly type liquid cooling camouflage garment based on flow-heat topological optimization, and belongs to the technical field of liquid cooling garment design. Comprising basic clothes, a liquid cooling film, a water cooling heat exchanger, a refrigerating device and a flow control assembly. By optimizing the channel layout in a liquid cooling circulation system composed of a liquid cooling film and a water cooling heat exchanger in the liquid cooling camouflage suit, the flow resistance is reduced, the channel flow speed and the heat exchange capacity are enhanced, the channel distribution with the maximum heat exchange amount is obtained, and a clear channel is obtained by introducing density filtration and a projection function. The highest heat exchange efficiency, the shortest flow path and the optimal heat dissipation uniformity of the cooling liquid in the liquid cooling suit are achieved, and then the comfort and the viability of a wearer in an extreme environment are improved. Through the multi-source flow-heat topological optimization design, it is ensured that the optimal heat exchange and flow optimization effects of the liquid cooling suit can be achieved when the multiple design domains are subjected to the effects of heat sources and cold sources in different forms at the same time.

Description

Technical Field

[0001] The invention belongs to the technical field of liquid cooling clothing design, and in particular relates to a fast-assembly liquid cooling camouflage clothing based on fluid-heat topology optimization. Background Art

[0002] As an efficient personal cooling equipment, liquid cooling suits are widely used for personal protection in high temperature environments such as aerospace, medical and industrial. However, the design of traditional liquid cooling suits has many limitations, such as low cooling efficiency, poor comfort, difficult maintenance and flexible assembly, which cannot meet the needs of modern high temperature operations for flexibility and efficient heat dissipation.

[0003] Most of the existing liquid cooling clothes adopt a fixed hose structure, and the hose is distributed on the fabric body. If the hose is damaged or leaks, it is difficult for the wearer to repair it in time outdoors.

[0004] Existing liquid-cooled clothing has limited coolant flow paths and heat exchange efficiency, resulting in insufficient cooling performance, uneven temperature distribution, and high energy consumption due to excessive hose flow resistance. In order to solve the above problems, topology optimization, as an advanced optimization design method, has been widely used in the field of thermal-fluid coupling. In the design of the cooling system of liquid-cooled clothing, topology optimization can achieve the optimal configuration of the cooling channel structure by adjusting the geometric structure and material distribution of the cooling system, maximize the heat dissipation area and enhance the heat transfer efficiency of the heat flow channel, thereby significantly improving the overall heat dissipation performance, but it still cannot achieve the ideal use effect. Summary of the invention

[0005] In order to solve the problems of low cooling efficiency and difficulty in rapid maintenance of traditional liquid-cooled clothing, the present invention achieves the goals of efficient heat dissipation, light carrying and rapid assembly, and further provides a quick-assembly liquid-cooled camouflage clothing based on flow-heat topology optimization. The liquid-cooled camouflage clothing uses topology optimization technology to regulate the flow channel structure layout inside the liquid cooling system, reduce flow resistance, enhance heat exchange capacity, achieve maximum heat dissipation effect and optimal fluid flow path, and introduces a new type of liquid-cooled film material, which is applied to the inner surface of the liquid-cooled camouflage clothing. Through modular design and quick plug-in interfaces, it is ensured that the liquid-cooled clothing can be quickly assembled, disassembled and maintained in a variety of environments, thereby improving the comfort and survivability of the wearer in high temperature environments.

[0006] The technical solution adopted by the present invention is:

[0007] A quick-assembly liquid-cooled camouflage uniform based on flow-heat topology optimization comprises a basic uniform, a liquid-cooling film, a water-cooling heat exchanger, a refrigeration device and a flow control component; a plurality of the liquid-cooling films are assembled on the inner surface of the basic uniform, the plurality of the liquid-cooling films are connected by pipelines, the water inlets and outlets of the plurality of liquid-cooling films are all connected to the water inlet and outlet of the water-cooling heat exchanger, the water-cooling heat exchanger is connected to the refrigeration device to form a liquid cooling circulation system, and the flow control component is connected to the liquid cooling circulation system.

[0008] Compared with the prior art, the present invention has the following beneficial effects:

[0009] 1. Most existing liquid-cooled clothing adopts a fixed hose structure, and the hose is distributed on the fabric body. If the hose is damaged or leaks, it is difficult for the wearer to repair it in time outdoors. In order to overcome this limitation, the liquid-cooled camouflage clothing of the present invention adopts a quick assembly design, introduces a new type of liquid-cooled film material, and applies it to the inner surface of the liquid-cooled camouflage clothing. The liquid-cooled circulation system composed of a liquid-cooled film and a water-cooled heat exchanger is modularized, and a modular design for rapid assembly and disassembly is adopted. Each liquid-cooled film is connected by a quick plug-in interface, so that the liquid-cooled clothing can be quickly assembled, disassembled and maintained at high-temperature working sites, enhancing the adaptability and practicality of the liquid-cooled clothing, which is particularly suitable for the cooling needs of outdoor high-temperature workers.

[0010] 2. Compared with the existing thermal-fluid coupling topology optimization cases, the innovation of this invention lies in the multi-source optimization design. The design model consists of two independent design domains and two pure fluid domains. Among them, an external heat source is applied in design domain I, and an external cold source is applied in design domain II. The liquid cooling circulation system composed of liquid cooling film and water-cooled heat exchanger uses this multi-source optimization design to ensure that when multiple design domains are simultaneously affected by different forms of heat sources and cold sources, the liquid cooling service can achieve the best heat exchange and flow effects, which is particularly suitable for the design requirements of complex cooling systems.

[0011] 3. At present, most of the research on liquid cooling clothing focuses on the optimization and improvement of existing channel structures, but lacks the exploration of new channel structures. Based on the flow-heat topology optimization method, the present invention proposes a design method for a rapid assembly type liquid cooling camouflage clothing. By optimizing the channel layout inside the liquid cooling circulation system composed of the liquid cooling film and the water cooling heat exchanger in the liquid cooling camouflage clothing, the flow resistance is reduced, the channel flow velocity and heat exchange capacity are enhanced, and the flow channel distribution with the maximum heat exchange capacity is obtained. The density filtering and projection function are introduced to obtain a clear flow channel. The highest heat exchange efficiency, shortest flow path and optimal heat dissipation uniformity of the cooling liquid in the liquid cooling clothing are achieved, thereby improving the comfort and survivability of the wearer in extreme environments.

[0012] The liquid-cooled camouflage suit of the present invention adopts a flow-heat topology optimization design, which can comprehensively improve the heat exchange efficiency and flow performance of the liquid cooling system. Compared with the traditional pipeline layout or empirical design method, the topology optimization structure has a greater degree of design freedom, can break through the limitations of the existing flow channel structure, and achieve more efficient heat exchange performance. Compared with the existing flow-heat topology technology, the present invention uses a multi-source flow-heat topology optimization design to ensure that when multiple design domains are simultaneously affected by different forms of heat sources and cold sources, the liquid-cooled suit can achieve the best heat exchange and flow optimization effect. And the optimization result is related to the location of the cold and hot sources, the coolant inlet parameters and the design domain of the liquid-cooled suit, and can be customized and optimized according to the actual application requirements, which is particularly suitable for the design requirements of the liquid cooling circulation system in the liquid-cooled suit.

[0013] 4. Through the design of the present invention, the liquid-cooled camouflage clothing not only has excellent cooling performance and comfort, but is also easy to maintain and flexibly assembled, and can effectively ensure the safety of personnel working in high temperature environments and outdoors, and has significant practical value and application prospects. The present invention is suitable for individual protective cooling in outdoor work and extreme environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural principle diagram of the present invention;

[0015] Figure 2 It is a schematic diagram of the design domain for a 2D simulation case;

[0016] Figure 3 It is the optimized material volume factor distribution diagram, temperature distribution diagram and velocity distribution diagram in the two-dimensional simulation case;

[0017] Figure 4 It is a 3D model of the TRA, TRB and TO models;

[0018] Figure 5 It is the pressure drop comparison, average temperature comparison and Nusselt number change diagram of the three models TRA, TRB and TO at different flow rates;

[0019] Figure 6 It is a physical diagram of the present invention;

[0020] Among them: 1. Basic clothing; 2. Liquid cooling film; 3. Water-cooled heat exchanger; 4. Refrigeration device; 5. Flow control component; 401. Semiconductor refrigeration plate; 402. Heat sink; 403. Cooling fan; 404. Portable voltage regulating power supply; 501. Liquid pump; 502. Throttle valve; 503. Check valve. DETAILED DESCRIPTION

[0021] In order to better understand the purpose, structure and function of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings.

[0022] like Figure 1 , Figure 6 As shown, a quick-assembly liquid-cooled camouflage uniform based on flow-heat topology optimization includes a basic garment 1, a liquid-cooling film 2, a water-cooling heat exchanger 3, a refrigeration device 4 and a flow control component 5; a plurality of the liquid-cooling films 2 are assembled on the inner surface of the basic garment 1, and the plurality of the liquid-cooling films 2 are connected by pipelines, and the water inlets and outlets of the plurality of liquid-cooling films 2 are connected to the water inlets and outlets of the water-cooling heat exchanger 3 by pipelines, the water-cooling heat exchanger 3 is connected to the refrigeration device 4 to form a liquid cooling circulation system, and the flow control component 5 is connected to the liquid cooling circulation system.

[0023] like Figure 1 As shown, each liquid cooling film 2 contains densely distributed microchannels to ensure that the cooling liquid can flow quickly inside the clothing and efficiently exchange heat with the human body surface. The liquid cooling film 2 is made of silicone material, is breathable, and is a flexible film that fits the human skin.

[0024] A quick plug-in interface is provided at the inlet and outlet connection of each liquid-cooling film 2. The liquid-cooling films 2 are connected by pipelines, and quick plug-in interfaces are provided at the inlet and outlet connections of the pipelines, so that the liquid-cooling films 2 can be quickly replaced through the quick plug-in interface.

[0025] like Figure 1 As shown, the water-cooled heat exchanger 3 contains densely distributed microchannels, which are connected to multiple liquid-cooled films 2 through pipelines. It is used to effectively cool the cooling liquid circulating in the liquid-cooled film 2. The water-cooled heat exchanger 3 is connected to the refrigeration device 4 to form a cooling circulation system;

[0026] like Figure 1 As shown, the refrigeration device 4 includes a semiconductor refrigeration sheet 401, a heat sink 402, a cooling fan 403 and a portable voltage-regulating power supply 404; the semiconductor refrigeration sheet 401, the heat sink 402 and the cooling fan 403 are sequentially arranged on the outside of the water-cooled heat exchanger 3, the cooling fan 403 is installed on the outside of the basic clothing 1, the semiconductor refrigeration sheet 401, the heat sink 402, the cooling fan 403 and the water-cooled heat exchanger 3 are arranged on the inside of the basic clothing 1, and the portable voltage-regulating power supply 404 is connected to the semiconductor refrigeration sheet 401 and the cooling fan 403 to provide power support for the semiconductor refrigeration sheet 401 and the cooling fan 403.

[0027] The liquid cooling film 2 and the water cooling heat exchanger 3 form a liquid cooling circulation system. The coolant flows in the liquid cooling circulation system, firstly absorbs the heat generated by the human body in the microchannel in the liquid cooling film 2, and then enters the water cooling heat exchanger 3 for cooling. The liquid cooling circulation system composed of the liquid cooling film 2 and the water cooling heat exchanger 3 is designed by using the flow-heat topology optimization technology, and realizes efficient heat exchange by optimizing and controlling the flow path and heat exchange area of ​​the cooling medium;

[0028] like Figure 1 As shown, the flow control component 5 includes a liquid pump 501, a throttle valve 502 and a one-way valve 503. The liquid pump 501 is arranged on the pipeline connecting the water-cooled heat exchanger 3 and the liquid-cooled film 2. The throttle valve 502 and the one-way valve 503 are also arranged on the pipeline.

[0029] By adjusting the flow rate of the coolant in the liquid cooling circulation system between the liquid cooling film 2 and the water cooling heat exchanger 3, it is ensured that the best cooling effect can be maintained under different ambient temperatures and human motion conditions;

[0030] like Figure 1 As shown, the basic garment 1 includes a highly elastic and breathable fabric layer, which is located between the liquid cooling film 2 and the human body to prevent the liquid cooling film 2 from directly contacting the human body and improve the wearing comfort. Multiple liquid cooling films 2 can be fixed on the basic garment 1 in series or parallel as needed; the basic garment 1 is sewn with Velcro at multiple locations, and Velcro is also sewn around the liquid cooling film 2. The basic garment 1 and the liquid cooling film 2 are connected by Velcro, so that the liquid cooling film 2 can flexibly change the attachment position and replace damaged parts.

[0031] The modular design of the liquid-cooled camouflage suit consists of a number of liquid-cooled films 2 and a water-cooled heat exchanger 3 on the inner surface of the liquid-cooled suit. Each module is equipped with a liquid-cooling channel and connected to each other through a quick-plug interface. The quick-plug interface is made of high-temperature resistant and corrosion-resistant materials, which can provide reliable connection in high temperature and harsh environments, while supporting rapid disassembly and replacement. The outer surface of the liquid-cooled camouflage suit adopts a camouflage pattern design, and uses the new liquid-cooled film 2 technology to provide camouflage effect while ensuring efficient heat dissipation;

[0032] The liquid-cooled film 2 and the water-cooled heat exchanger 3 form a liquid-cooled circulation system. The internal flow channel of the circulation system is designed based on the flow-heat topology optimization technology, and the heat exchange performance and flow performance in the liquid-cooled system are synergistically optimized. The design model consists of two independent design domains and two pure fluid domains (inlet and outlet). Among them, an external heat source is applied in the design domain I, and an external cold source is applied in the design domain II. The liquid-cooled circulation system composed of the liquid-cooled film 2 and the water-cooled heat exchanger 3 uses this multi-source optimization design to ensure that when multiple design domains are simultaneously affected by different forms of heat sources and cold sources, the liquid-cooled suit can achieve the best heat exchange and flow effects, which is particularly suitable for the design requirements of the liquid-cooled circulation system.

[0033] like Figure 2 to Figure 5 As shown, the internal flow channel of the liquid cooling circulation system is designed based on the fluid-heat topology optimization technology, and the fluid-heat dual-objective topology optimization steps are as follows:

[0034] Step 1: According to the material properties, geometric dimensions and coolant inlet position of the liquid-cooled camouflage uniform, the optimization range of design domain I and design domain II is determined, and a two-dimensional topological optimization model integrating design domain I and design domain II is established. The model contains the diverse distribution of heat sources and cold sources.

[0035] Step 2: Introduce the design variable γ, and use the interpolation function to establish the relationship between the material properties of each design domain in the liquid cooling system and the design variables; the design variable γ is used to control the material distribution in different regions, γ = 0 represents the solid domain, and γ = 1 represents the fluid domain;

[0036] Step 3: Design the objective functions of flow and heat transfer for design domain I and design domain II respectively, form the overall flow-heat dual-objective optimization function through weighted summation, and combine the heat source and cold source conditions in the design domain to determine the boundary conditions and constraints of topology optimization (including constant flow velocity at the inlet, constant pressure at the outlet, no-slip condition on the solid wall, constant heat flow condition of the heat source in design domain I, constant cold load condition of the cold source in design domain II, and external adiabatic condition) and constraints (including geometric constraints, material property constraints, flow performance constraints, and thermal performance constraints) to ensure that the flow and heat transfer behavior of the design domain are effectively optimized;

[0037] Step 4: By solving the control equations, the two design domains are iteratively optimized, the design variable γ is updated, and the fuzzy problem of the channel boundary in the liquid cooling system is eliminated through density filtering and projection function, and the optimized material distribution, temperature distribution and flow velocity distribution diagram are output;

[0038] Step 5: Based on the optimized material distribution map, the 3D model of the liquid-cooled camouflage uniform is reconstructed to ensure that the interaction between the cold and heat sources in the two design domains is optimally controlled;

[0039] Step 6: Conduct 3D simulation analysis on the reconstructed liquid-cooled camouflage uniform to evaluate the flow and heat transfer performance of the liquid cooling system under the action of multiple heat sources and cold sources;

[0040] Step 7: According to the flow performance, heat transfer performance and comfort index of the liquid-cooled camouflage uniform, determine whether the design after topology optimization meets the requirements. If the design meets the requirements, output the design; if it does not meet the requirements, adjust the optimization parameters and repeat steps 4 to 7 until the expected optimization effect is achieved.

[0041] The present invention ensures that the liquid cooling circulation system in the liquid cooling camouflage uniform achieves optimal heat exchange performance and flow performance at the same time by applying different forms of heat sources and cold sources in multiple design domains, and is particularly suitable for individual cooling needs in outdoor high-temperature operations.

[0042] The liquid cooling film 2 adopts a topologically optimized flow channel structure layout. By optimizing the shape and distribution of the microchannels, the cooling liquid flows more efficiently in the liquid cooling suit, improving the overall heat dissipation performance. At the same time, the design of modular cooling units and quick plug-in interfaces allows the liquid cooling suit to be quickly assembled and disassembled, suitable for a variety of mission requirements.

[0043] The present invention provides an efficient, convenient and comfortable liquid-cooled camouflage suit suitable for use in a high-temperature environment. The liquid-cooled film 2 on the inner surface is made of a flexible material with high thermal conductivity, and an optimized microchannel structure is distributed inside the liquid-cooled camouflage suit to guide the flow of cooling liquid in the liquid-cooled camouflage suit. The microchannel structure is based on the flow-heat dual-objective topology optimization to achieve the coordinated optimization of the heat exchange performance and flow characteristics of the internal circulation channel of the liquid cooling system, such as Figure 2 As shown in the figure. The channel layout obtained by density filtering and projection function optimization realizes efficient flow and heat transfer of cooling liquid, where:

[0044] The density-based topology optimization method is used to design the liquid cooling film 2 and the water cooling heat exchanger 3 to form a liquid cooling circulation system. First, the physical model of the system should be established. Considering that the liquid cooling system is composed of multiple liquid cooling films 2, the calculation time can be reduced without changing the principle. Here, only a single liquid cooling film 2 and a water cooling heat exchanger 3 are used to form a liquid cooling circulation system for simulation analysis, and a two-dimensional topology optimization design domain structure is constructed, such as Figure 2 As shown. In order to strike a balance between flow dissipation and thermal performance, a multi-objective optimization problem is proposed. The liquid cooling circulation system is provided with cooling inlet channels and cooling outlet channels respectively. The arrow directions indicate the inlet and outlet of the fluid. The empty area in the middle is used for the material distribution of solid and fluid, which is called the design domain Ω, where γ is used as the design variable. The value range of the design variable γ is 0 to 1, γ equals 0 for the solid domain, and γ equals 1 for the fluid domain. The design model consists of two design domains (square Ⅰ and rectangle Ⅱ) and two pure fluid domains (inlet and outlet). In design domain Ⅰ, the entire design area is subjected to a uniform single heat source. In design domain Ⅱ, the cooling load is applied to the central area of ​​the design domain.

[0045] The following assumptions are made for the mathematical model of heat transfer and flow:

[0046] ① The flow of the working fluid (coolant) in the channel is incompressible, laminar and steady;

[0047] ②The material in the design domain is porous medium;

[0048] ③The flow field is controlled by the continuity equation and the Navier-Stokes equation;

[0049] ④ Add a damping term to the NS equation to represent the resistance encountered by the fluid when flowing through the fluid-solid porous medium.

[0050] The fluid flow boundary conditions for topological optimization of the liquid cooling circulation system include setting constant velocity boundary conditions at the inlet of design domain I and design domain II, and setting constant pressure boundary conditions at the outlet. No-slip boundary conditions are used at the solid wall; heat transfer boundary conditions include applying constant heat flow boundary conditions in the design domain I area, applying constant cold load boundary conditions in the design domain II area, and setting adiabatic boundary conditions on the external boundaries. Constraints include geometric constraints, which require that the geometric dimensions of the microchannels in the liquid cooling system meet the manufacturing requirements; material property constraints ensure that the material properties match the flow and heat transfer targets by setting the design variable γ; flow performance constraints ensure that the system pressure drop is within a reasonable range to avoid excessive power consumption while maintaining smooth fluid flow; thermal performance constraints ensure uniform temperature distribution and high heat transfer efficiency in the optimized design, avoid local overheating or insufficient cooling, and ultimately ensure the comfort and heat dissipation efficiency of the liquid-cooled camouflage uniform.

[0051] Flow Governing Equations: Topology optimization is performed using a conjugate heat transfer model. The flow field can be governed by the incompressible Navier-Stokes equations, which consist of the following continuity equation and momentum equation:

[0052]

[0053]

[0054] Where u and p are the velocity and pressure of the fluid, ρ is the fluid density, and μ is the fluid viscosity coefficient. is the transposed tensor of the velocity gradient, and α is the local damping coefficient of the design domain.

[0055] The temperature field is governed by the energy equation as shown below:

[0056]

[0057] In the formula, C is the specific heat capacity at constant pressure, k is the thermal conductivity, Q is the heat source term, is the convection term for the fluid flowing into and out of the control volume, is the heat conduction term.

[0058] The design variable γ is introduced and the damping coefficient is associated with the design variable γ to control the distribution of fluid and solid materials. The design variable γ can take values ​​between 0 and 1 to define the material type. γ = 0 represents solid material, γ = 1 represents fluid material, and γ = 0.5 represents the solid-liquid interface. For two dimensions, the boundary heat transfer of the three-dimensional problem can be converted into a heat source, as shown in the following formula:

[0059] Q = (1-γ)h(T r -T) (4)

[0060] Where h is the power density, W / (m 3 ·K), which is the relationship between power output or absorption per unit volume and temperature difference, T r is the reference temperature and T is the local temperature.

[0061] For the convenience of calculation, the continuity equation, momentum equation and energy equation are listed in dimensionless form as follows:

[0062]

[0063] In the formula, u * and p * are the dimensionless velocity and dimensionless pressure of the fluid, ρ * is the dimensionless fluid density, μ * is the dimensionless fluid viscosity coefficient, α * is the dimensionless local damping coefficient of the design domain, C * is the dimensionless specific heat at constant pressure, k * is the dimensionless thermal conductivity, is the dimensionless convection term for the fluid flowing into and out of the control volume, is the dimensionless heat conduction term, Q * is the dimensionless heat source term. T * is the dimensionless temperature.

[0064] The dimensionless rule for variables is:

[0065]

[0066] In the formula, T, T 100 and T 0 are the local temperature, the overall average temperature of the design domain, and the inlet temperature, respectively.

[0067] U is the characteristic velocity, ρ f is the fluid density, c f is the constant pressure specific heat capacity of the fluid, k f is the thermal conductivity of the fluid, μ f is the dynamic viscosity of the fluid, u 0 is the reference velocity at the inlet, Re is the Reynolds number, Pr is the Prandtl number, and L is the characteristic length;

[0068] The two-dimensional heat source replaces the three-dimensional problem boundary heat transfer and becomes dimensionless:

[0069]

[0070] In the formula, is the dimensionless reference temperature and h is the heat generation coefficient, which is the proportionality constant between the heat flux and the thermodynamic driving force of the heat flow.

[0071] The fluid and solid materials in the design domain are optimally arranged to find the best flow channel distribution structure. The velocity-related damping term is added to the momentum conservation equation through the Darcy penalty model to simulate the friction force on the fluid in the design domain. In order to characterize the relationship between the density and volume force corresponding to the solid domain and the fluid domain, α * (x) is a continuous mapping determined by the design variable γ using the interpolation function, that is:

[0072]

[0073] In the formula, q is used to adjust α * (x) is the penalty factor for the shape of the function, and α s Related to the dimensionless Darcy number Da, α s * is the damping coefficient of the solid domain, is the damping coefficient of the fluid domain, q a is the penalty factor;

[0074] The solution in the solid part (γ = 0) essentially yields u = 0. Then and α s * It is expressed as:

[0075]

[0076] According to equations (10) and (11), equations (6) and (7) can be converted into:

[0077]

[0078]

[0079] The temperature field of the fluid and solid in the design domain can be described by equation (3). Similarly, a convex function is used to describe the density ρ in equation (3). * , thermal conductivity k * and specific heat capacity C * Perform RAMP interpolation:

[0080]

[0081]

[0082]

[0083] Where the subscripts f and s represent the fluid and solid material properties, respectively. s * For a fixed density, and is the specific heat capacity at constant pressure of the fluid domain and the solid domain, and k s * is the thermal conductivity of the fluid domain and the solid domain, q ρ ,q C and q k are the penalty factors for density-to-constant-pressure heat capacity, thermal conductivity, and power interpolation, respectively. By setting the penalty factor, the intermediate density value is penalized, so that the original design variables that vary in the [0,1] interval are discretized, and finally the optimization results approximating 0 and 1 are obtained. Choosing appropriate values ​​can reduce the generation of grayscale units. In this study, the penalty factor q and Darcy number Da are set to 10, respectively. -2 and 10 -4 Assuming that the coolant is water at 20°C under standard atmospheric pressure (ignoring temperature changes), the Prandtl number Pr is set to 6.78. In addition, the complexity of the channel layout increases with the dimensionless coefficient h * In this paper, for manufacturing considerations, h * is set to 100. For brevity, we will remove the asterisks from dimensionless variables, u * 、p * , T * 、h * , α * , and simply denote them as u, p, T, h, α and

[0084] The heat transfer performance of the cooling system is determined by the heat transfer efficiency and pressure loss of the cooling system. The main focus of topology optimization is to reduce the power consumption in the fluid, which is characterized by pressure drop. The goal of optimization is to increase the heat transfer and reduce the pressure drop. The pressure drop can be characterized by the total potential energy in the volume:

[0085]

[0086] Where ψ is the total potential energy, μ is the fluid dynamic viscosity, and α(x) is the interpolated porous medium resistance coefficient. Ω refers to the entire design domain.

[0087] Considering the need to improve the uniformity of temperature distribution of the structure, the temperature variance is selected as the objective function for research. The goal of topology optimization is to minimize the temperature variance of the design domain. The maximum heat transfer φ in the design domain can be calculated by the following formula:

[0088] φ=∫ Ω (1-γ)h(1-T)dΩ (18)

[0089] Combining the functions of formulas (17) and (18) to achieve the requirements of the engineering project, the optimization objective function is as follows:

[0090] Π=-w 1 φ+w 2 ψ (19)

[0091] Among them, w 1 and w 2 is the weight factor of the multi-objective function.

[0092] The mathematical model of the topology optimization problem is:

[0093]

[0094] Where Ω is the design domain, γ i is the design variable; the volume of the solid domain is the total volume of the design domain minus the volume of the fluid domain; γ ranges from 0 to 1. In this work, the topology optimization process is implemented using the laminar flow and conjugate heat transfer physics in the multi-physics simulation software. The temperature field, velocity field, and design variable field are all discretized using Lagrangian linear units. The wall is set as an anti-slip boundary, and the outlet is considered as a static pressure outlet.

[0095] The topology optimization is realized by numerical iteration algorithm, and the control equations are discretized by finite element method. The two-dimensional model is divided into 11,765 quadrilateral elements. In order to avoid mesh dependence and checkerboard problem (numerical instability), the Helmholtz filter is used in this paper, which is expressed as

[0096] In the TO problem, a density filter is needed to avoid grid dependence. In the thermal fluid TO problem, if there is no density filter, it may be in an ill-posed state

[41] . This paper uses the Helmholtz filter based on partial differential equations, which is defined as:

[0097]

[0098] In the formula, is the filter design variable, r is the filter radius, and in this study, the grid cell size is taken as the filter radius r. Hyperbolic tangent projection is used to reduce the intermediate values ​​in the design domain after filtering:

[0099]

[0100] In the formula, is the output design variable. β and β are the projection point and slope respectively, β=1-γ. In this paper, γ β The slope β is set to 0.5 and 8, and the moving asymptote method (MMA) is used to optimize the field of the slope β. The sensitivity of the objective function and the constraints is calculated by the adjoint method. When the relative change of the objective function during the iteration is less than 1×10 -3The numerical results can be considered to be converged when . In addition, the optimization is set to run for a maximum of 400 iterations.

[0101] The film fluid is deionized water, the solid domain material is Ecoflex 00-50, the inlet flow rate is 0.1 m / s, the boundary condition is pressure-outlet, and the ambient temperature is 40 °C. Table 1 lists the parameters of the TO simulation. The thermophysical parameters and other boundary conditions in the simulation are shown in Table 2.

[0102] Table 1 Topology optimization simulation parameters

[0103]

[0104] Table 2 Material properties used in the calculation

[0105]

[0106] Figure 3 The topology optimization results, streamline contours, and temperature distribution under a weighting factor ratio of 1:1 are shown. The total length of the convection heat transfer boundary is 2867 mm, and the effective heat transfer area A eff , pressure drop and average temperature are 10067mm 2 , 35.6Pa, 13.9℃.

[0107] The liquid cooling film 2 and the water cooling heat exchanger 3 form a liquid cooling circulation system. The coolant flows in the liquid cooling circulation system, first absorbing the heat generated by the human body in the microchannels in the liquid cooling film 2, and then enters the water cooling heat exchanger 3 for cooling. The liquid cooling circulation system composed of the liquid cooling film 2 and the water cooling heat exchanger 3 is designed using the flow-heat topology optimization technology, and realizes efficient heat exchange by optimizing and controlling the flow path and heat exchange area of ​​the cooling medium;

[0108] Through the design of flow-heat topology optimization technology, a topology optimized flow channel structure with a volume fraction of 0.6 is formed to achieve the best heat transfer efficiency and minimum pressure loss.

[0109] The channel structure of the liquid cooling film 2 uses the traditional circulation channel (TRA, TRB) and the topology optimization channel (TO) for comparative analysis. The TRA model uses a standard serpentine arrangement of the channel structure ( Figure 4 a), TRB model adopts the standard parallel distribution flow channel structure ( Figure 4 b), while the TO model is the topology optimization design result with a volume fraction of 0.6 ( Figure 4 c). The three models are compared under the same boundary conditions to evaluate their heat transfer efficiency and pressure loss.

[0110] The flow and heat transfer performance of the liquid-cooled film 2 were simulated using multi-physics coupling simulation software. The initial conditions were set to a constant flow range of 40 mL / min to 600 mL / min and an ambient temperature of 20 °C. The heat source temperature was 60 °C and the cooling load was 150 W. During the simulation, 7.5 to 9.1 million grids were used for calculation to ensure the accuracy and stability of the results.

[0111] Figure 5 The pressure drop comparison, average temperature comparison and Nusselt number change of the three models at different flow rates of 40mL / min to 600mL / min. Figure 5 The simulation results show that the TO model exhibits a lower pressure drop than the TRA and TRB models ( Figure 5 a Comparison of pressure drop of three models at different flow rates) and higher heat transfer efficiency. Under the same flow conditions, the average temperature of the TO model is significantly lower than that of the TRA and TRB models ( Figure 5 b Comparison of average temperature of the three models at different flow rates), and shows a more uniform temperature distribution, a higher Nusselt number ( Figure 5 c Comparison of the Nusselt numbers of the three models at different flow rates), indicating that the optimized flow channel structure has obvious advantages in heat transfer performance.

[0112] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A fast-assembly liquid-cooled camouflage uniform based on fluid-thermal topology optimization, characterized in that: The invention comprises a basic garment (1), a liquid cooling film (2), a water cooling heat exchanger (3), a refrigeration device (4) and a flow control component (5); a plurality of the liquid cooling films (2) are assembled on the inner surface of the basic garment (1); the plurality of the liquid cooling films (2) are connected by pipelines; the water inlets and outlets of the plurality of liquid cooling films (2) are connected to the water inlet and outlet of the water cooling heat exchanger (3); the water cooling heat exchanger (3) is connected to the refrigeration device (4) to form a liquid cooling circulation system; the flow control component (5) is connected to the liquid cooling circulation system.

2. According to claim 1, a rapid assembly type liquid cooling camouflage uniform based on fluid-thermal topology optimization is characterized in that: Each liquid cooling film (2) contains densely distributed micro channels inside, and the liquid cooling film (2) is made of silica gel material.

3. A fast-assembly liquid-cooled camouflage uniform based on fluid-thermal topology optimization according to claim 1 or 2, characterized in that: A quick plug-in interface is provided at the inlet and outlet connection of each of the liquid cooling films (2), the liquid cooling films (2) are connected via pipelines, and quick plug-in interfaces are provided at the inlet and outlet connections of the pipelines, and the liquid cooling films (2) are quickly replaced via the quick plug-in interfaces.

4. The rapid assembly type liquid-cooled camouflage uniform based on fluid-thermal topology optimization according to claim 3 is characterized in that: The water-cooled heat exchanger (3) contains densely distributed microchannels inside, and is connected to the plurality of liquid-cooled films (2) via pipelines.

5. The rapid assembly type liquid cooling camouflage uniform based on fluid-thermal topology optimization according to claim 1 is characterized in that: The refrigeration device (4) comprises a semiconductor refrigeration sheet (401), a heat sink (402), a cooling fan (403) and a portable voltage-regulating power supply (404); the semiconductor refrigeration sheet (401), the heat sink (402) and the cooling fan (403) are sequentially arranged on the outside of the water-cooled heat exchanger (3); the cooling fan (403) is installed on the outside of the basic clothing (1); the semiconductor refrigeration sheet (401), the heat sink (402), the cooling fan (403) and the water-cooled heat exchanger (3) are arranged on the inside of the basic clothing (1); and the portable voltage-regulating power supply (404) is connected to the semiconductor refrigeration sheet (401) and the cooling fan (403).

6. The rapid assembly type liquid cooling camouflage uniform based on fluid-thermal topology optimization according to claim 1 is characterized in that: The flow control component (5) comprises a liquid pump (501), a throttle valve (502) and a one-way valve (503); the liquid pump (501) is arranged on a pipeline connecting the water-cooled heat exchanger (3) and the liquid-cooled film (2); and the throttle valve (502) and the one-way valve (503) are also arranged on the pipeline.

7. The rapid assembly type liquid cooling camouflage uniform based on fluid-thermal topology optimization according to claim 1 is characterized in that: The basic garment (1) is sewn with Velcro at multiple locations, and Velcro is sewn around the liquid cooling film (2). The basic garment (1) and the liquid cooling film (2) are connected via the Velcro.

8. The rapid assembly type liquid cooling camouflage uniform based on fluid-thermal topology optimization according to claim 1 is characterized in that: The internal flow channel of the liquid cooling circulation system is designed based on the flow-heat topology optimization technology, and the flow-heat dual-objective topology optimization steps are as follows: Step 1: According to the material properties, geometric dimensions and coolant inlet position of the liquid-cooled camouflage uniform, the optimization range of design domain I and design domain II is determined, and a two-dimensional topological optimization model integrating design domain I and design domain II is established. The model contains the diverse distribution of heat sources and cold sources. Step 2: Introduce the design variable γ and use the interpolation function to establish the relationship between the material properties of each design domain and the design variables in the liquid cooling system; Step 3: Design the objective functions of flow and heat transfer for design domain I and design domain II respectively, and form the overall flow-heat dual-objective optimization function through weighted summation. Determine the boundary conditions for topology optimization by combining the heat source and cold source conditions in the design domain; Step 4: By solving the control equations, the two design domains are iteratively optimized, the design variable γ is updated, and the fuzzy problem of the channel boundary in the liquid cooling system is eliminated through density filtering and projection function, and the optimized material distribution, temperature distribution and flow velocity distribution diagram are output; Step 5: Based on the optimized material distribution map, the 3D model of the liquid-cooled camouflage uniform is reconstructed to ensure that the interaction between the cold and heat sources in the two design domains is optimally controlled; Step 6: Conduct 3D simulation analysis on the reconstructed liquid-cooled camouflage uniform to evaluate the flow and heat transfer performance of the liquid cooling system under the action of multiple heat sources and cold sources; Step 7: According to the flow performance, heat transfer performance and comfort index of the liquid-cooled camouflage uniform, determine whether the design after topology optimization meets the requirements. If the design meets the requirements, output the design; if it does not meet the requirements, adjust the optimization parameters and repeat steps 4 to 7 until the expected optimization effect is achieved.

9. The rapid assembly type liquid cooling camouflage uniform based on fluid-thermal topology optimization according to claim 8 is characterized in that: The process of determining the boundary conditions and constraint conditions of topology optimization in step 3 is as follows: The governing equations for the flow are: Where u and p are the velocity and pressure of the fluid, ρ is the fluid density, μ is the fluid viscosity coefficient, and α is the local damping coefficient of the design domain. is the transposed tensor of the velocity gradient; The temperature field is governed by the energy equation as shown below: In the formula, C is the specific heat capacity at constant pressure, k is the thermal conductivity, Q is the heat source term, is the convection term for the fluid flowing into and out of the control volume, is the heat conduction term; The design variable γ is introduced, and the damping coefficient is associated with the design variable γ. The value of the design variable γ between 0 and 1 defines the material type. γ = 0 represents solid material, γ = 1 represents fluid material, and γ = 0.5 represents the solid-liquid interface. For two dimensions, the boundary heat transfer of the three-dimensional problem is converted into a heat source, as shown in the following formula: Q=(1-γ)h(T r -T) (4) Where h is the power density, W / (m 3 K), which is the relationship between power output or absorption per unit volume and temperature difference; T r is the reference temperature, T is the local temperature; The continuity equation, momentum equation, and energy equation are expressed in dimensionless form as: In the formula, u * and p * are the dimensionless velocity and dimensionless pressure of the fluid, ρ * is the dimensionless fluid density, μ * is the dimensionless fluid viscosity coefficient, α * is the dimensionless local damping coefficient of the design domain, C * is the dimensionless specific heat at constant pressure, k * is the dimensionless thermal conductivity, is the dimensionless convection term for the fluid flowing into and out of the control volume, is the dimensionless heat conduction term, Q * is the dimensionless heat source term; T * is the dimensionless temperature; The dimensionless rule for variables is: In the formula, T, T 100 and T0 are the local temperature, the overall average temperature of the design domain, and the inlet temperature, respectively; U is the characteristic velocity, ρ f is the fluid density, c f is the constant pressure specific heat capacity of the fluid, k f is the thermal conductivity of the fluid, μ f is the dynamic viscosity of the fluid, u0 is the reference velocity at the inlet, Re is the Reynolds number, Pr is the Prandtl number, and L is the characteristic length; The two-dimensional heat source replaces the three-dimensional problem boundary heat transfer and becomes dimensionless: Where h is the heat production coefficient, which is the proportionality constant between the heat flux and the thermodynamic driving force of the heat flow; T r * is the dimensionless reference temperature; The Darcy penalty model is used to add a velocity-related damping term to the momentum conservation equation to simulate the friction force exerted on the fluid in the design domain. In order to characterize the relationship between the density and volume force corresponding to the solid domain and the fluid domain, α * (x) is a continuous mapping determined by the design variable γ using the interpolation function, that is: In the formula, q is used to adjust α * (x) is the penalty factor for the shape of the function, and α s Related to the dimensionless Darcy number Da, α s * is the damping coefficient of the solid domain, α f * is the damping coefficient of the fluid domain, q a is the penalty factor; The solution in the solid part (γ = 0) basically gives u = 0, and then α f * and α s * It is expressed as: According to equations (10) and (11), equations (6) and (7) can be converted into: The temperature field of the fluid and solid in the design domain is described by equation (3). Similarly, a convex function is used to describe the density ρ in equation (3). * , thermal conductivity k * and specific heat capacity C * Perform RAMP interpolation: Where the subscripts f and s represent the fluid and solid material properties, respectively, and ρ s * For a fixed density, C f * and C s * is the specific heat capacity at constant pressure of the fluid domain and the solid domain, k f * and k s * is the thermal conductivity of the fluid domain and the solid domain, q ρ ,q C and q k are the penalty factors for density ratio constant pressure heat capacity, thermal conductivity and power interpolation respectively. By setting the penalty factor, the intermediate density value is penalized, so that the original design variables in the [0,1] interval are discretized, and finally the optimization results approximating 0 and 1 are obtained. Choosing appropriate values ​​can reduce the generation of gray units. The penalty factor q and Darcy number Da are set to 10 respectively. -2 and 10 -4 , assuming that the coolant is water at 20°C under standard atmospheric pressure, the Prandtl number Pr is set to 6.78, h * Set to 100 to remove the asterisk for dimensionless variables, u * 、p * , T * 、h * , α * , and simply denote them as u, p, T, h, α and The pressure drop is characterized by the total potential energy within the volume: Where μ is the fluid dynamic viscosity, α(x) is the interpolated porous medium resistance coefficient, Ω refers to the entire design domain, and ψ is the total potential energy; The maximum heat transfer φ in the design domain can be calculated by the following formula: φ=∫ Ω (1-γ)h(1-T)dΩ (18) Combining the functions of formulas (17) and (18) to achieve the requirements of the engineering project, the optimization objective function is as follows: Π=-w1φ+w2ψ (19) Among them, w1 and w2 are weight factors of the multi-objective function; The mathematical model of the topology optimization problem is: Where Ω is the design domain, γ i is the design variable; the volume of the solid domain is the total volume of the design domain minus the volume of the fluid domain; the range of γ is between 0 and 1. The topology optimization process is realized by using the laminar flow and conjugate heat transfer physical fields in the multi-physics simulation software. The temperature field, velocity field and design variable field are all discretized using Lagrangian linear units. The wall is set as an anti-slip boundary, and the outlet is regarded as a static pressure outlet. The topology optimization was realized by numerical iteration algorithm, and the control equations were discretized by finite element method. The two-dimensional model was divided into 11,765 quadrilateral units. Use a Helmholtz filter based on a partial differential equation, defined as: In the formula, is the filter design variable, r is the filter radius, the grid unit size is taken as the filter radius r, and the hyperbolic tangent projection is used to reduce the intermediate values ​​in the design domain after filtering: In the formula, is the output design variable, γ β and β are the projection point and slope respectively, β=1-γ,γ β The slope β is set to 0.5 and 8, and the moving asymptote method (MMA) is used to optimize the field of the slope β. The sensitivity of the objective function and the constraint is calculated by the adjoint method. When the relative change of the objective function during the iteration is less than 1×10 -3 When , the numerical results can be considered to be convergent.

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