Heat dissipation analysis optimization method for field domain temperature measurement equipment based on CFD simulation analysis

Abstract

The invention discloses a heat dissipation analysis optimization method for field domain temperature measurement equipment based on CFD simulation analysis. The heat dissipation analysis optimization method comprises the following steps: establishing a heat production model of the field domain temperature measurement equipment; establishing a simulation three-dimensional physical model of the field domain temperature measurement equipment based on the geometrical shape of the field domain temperature measurement equipment, and defining boundary conditions and material attributes of the field domain temperature measurement equipment; carrying out element grid division on a calculation area of the simulation three-dimensional physical model of the field domain temperature measurement equipment; performing simulation solution on the simulation three-dimensional physical model of the field domain temperature measurement equipment to obtain a temperature cloud picture, and then obtaining a local highest temperature and a distribution condition area in the field domain temperature measurement equipment; performing optimization design on the simulation three-dimensional physical model and the boundary condition according to the local highest temperature and the distribution condition area in the field domain temperature measurement equipment; then simulation analysis and optimization design are carried out again until the local highest temperature of the field domain temperature measurement equipment reaches the temperature range of normal work of the equipment after optimization; and safe and stable operation of the field domain temperature measurement equipment is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature measuring equipment, and in particular to a heat dissipation analysis optimization method of a field temperature measuring equipment based on CFD simulation analysis. Background Art

[0002] Traditional power equipment maintenance and inspection requires a lot of manpower and material costs, and has a high risk factor. The dual-spectrum long-distance field temperature measurement equipment can detect field power equipment in real time, feedback abnormalities in a timely manner, and transmit data in real time. It is an intelligent terminal system for unmanned substations. The dual-spectrum long-distance field temperature measurement system can achieve real-time temperature measurement, health management of power equipment, and intelligent operation status evaluation. It can timely warn of power plant equipment failures and accurately display the fault point. When the dual-spectrum long-distance field temperature measurement equipment is working, the components such as the red and white light cameras, router modules, switch modules, temperature control boards and main control boards will generate a lot of heat due to the operation of electronic devices; this heat will spread from the source to the surrounding environment, resulting in a high heat flux density in the internal space of the equipment, thereby increasing the temperature of the equipment; inside the sealed chassis, due to the relatively small space and the stacking of components, it is not conducive to the formation of effective airflow circulation; as a result, the air flow is blocked, forming a local airflow dead zone, and the heat cannot be dissipated, which may cause damage to the electronic devices in the field temperature measurement equipment; however, due to the different arrangement and installation positions of the electronic devices in the field temperature measurement equipment, the compactness of the stacking is different, and the degree of integration is also different; therefore, the temperature distribution and temperature change of different types of field temperature measurement equipment are different. If the temperature in the field temperature measurement equipment exceeds the temperature range of normal operation of various electronic devices in the field temperature measurement equipment, the electronic devices in the field temperature measurement equipment will be damaged, and the field temperature measurement equipment will not be able to perform normal temperature measurement. Summary of the invention

[0003] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a heat dissipation analysis and optimization method for field temperature measurement equipment based on CFD simulation analysis, analyzes the temperature distribution and changes of the field temperature measurement equipment during normal operation, determines the local maximum temperature in the field temperature measurement equipment, optimizes the design of the physical structure and boundary conditions of the field temperature measurement equipment, and ensures that the temperature of the local high-temperature zone in the field temperature measurement equipment reaches the temperature range of normal operation of the equipment.

[0004] Technical solution: To achieve the above purpose, the present invention provides a heat dissipation analysis and optimization method for field temperature measurement equipment based on CFD simulation analysis, comprising the following steps:

[0005] S1. Based on the constructed mathematical model of heat transfer of the field temperature measurement equipment, a heat generation model of the field temperature measurement equipment is established;

[0006] S2. establishing a simulated three-dimensional physical model of the field temperature measurement device based on the geometric shape of the field temperature measurement device, defining boundary conditions for the simulated three-dimensional physical model of the field temperature measurement device, and defining material properties of the field temperature measurement device;

[0007] S3, performing elemental grid division on the calculation area of ​​the simulated three-dimensional physical model of the field temperature measurement equipment, and checking whether the grid division meets the solution standard, otherwise re-gridding is performed, and if yes, proceeding to the next step;

[0008] S4. Simulate and solve the simulated three-dimensional physical model of the field temperature measurement device to obtain the distribution and change of the temperature when the field temperature measurement device reaches a thermal steady state;

[0009] S5. According to the temperature cloud map obtained in S4, the local maximum temperature and distribution area in the field temperature measurement equipment are obtained;

[0010] S6. According to the simulated three-dimensional physical model, the boundary conditions of the model and the material properties, a physical field temperature measurement device is built and operated according to the set conditions to detect whether the error between the actual temperature and the simulation analysis in S4 is within an acceptable range. If yes, proceed to the next step;

[0011] S7. Based on the conclusion of S5, optimize the model and boundary conditions of S2;

[0012] S8. Execute S3-S7 until the local maximum temperature of the optimized field temperature measurement device reaches the temperature range of normal operation of the device.

[0013] Furthermore, the mathematical model of heat transfer of the field temperature measurement equipment is constructed by expressing the proportional relationship between the heat flow generated per unit area and the temperature gradient in the medium. The proportional relationship expression is as follows:

[0014]

[0015] In the formula, Q is the heat flow, A is the surface area through which the heat flows, λ is the thermal conductivity of the fluid, and “-” indicates that the heat flows in the opposite temperature gradient;

[0016] When λ is constant and there is no heat source in the medium, the temperature change is expressed by the diffusion equation, which is as follows:

[0017]

[0018] Where c is the specific heat capacity and ρ is the density of the medium.

[0019] Furthermore, the diffusion equation expressing the temperature change is converted from a three-dimensional formula to a one-dimensional formula to obtain a one-dimensional temperature gradient expression, and the expression is substituted into the proportional relationship expression to obtain the heat flow formula; the temperature remains unchanged and the temperature gradient remains constant, and the one-dimensional temperature gradient expression is as follows:

[0020]

[0021] In the formula, D is the thickness of the device shell, T1 is the temperature of the device cavity, and T2 is the ambient temperature of the field temperature measurement device. Substituting the one-dimensional temperature gradient expression into the proportional relationship expression, the heat flow formula is obtained:

[0022]

[0023] Furthermore, the shell of the field temperature measurement equipment is divided into several infinitely thin and uniform outer shell layers, and the heat flow formula for each layer is obtained; the heat flow formula for the nth layer is:

[0024]

[0025] Where, T n 、T n+1 Represent the temperatures of the two layers of n layers,

[0026] When the heat flux through each layer is equal, the heat flow formula for the nth layer is as follows:

[0027]

[0028] Furthermore, according to the temperature T outside the field temperature measurement equipment shell n and T N , the heat flow formula of the shell of the field temperature measurement equipment is obtained by the recursive method, and the thermal resistance of the shell is introduced to simplify it. The simplified formula is used as the mathematical model of heat transfer of the field temperature measurement equipment;

[0029]

[0030] Further, in S2, the physical structure of the field temperature measurement equipment includes a sealed equipment shell, and the equipment shell includes a main control board, a red light camera, a red light camera control board, a switch circuit board, a router module, a first white light camera module and a second white light camera module; the red light camera is installed on the red light camera control board, and the first white light camera module and the second white light camera module are respectively arranged on both sides of the red light camera; the main control board is horizontally fixed to the bottom of the inner wall of the equipment shell, and the main control board is located on the side of the red light camera away from the lens end; the switch circuit board is parallel to the top of the main control board, and a heat dissipation cavity is formed between the switch circuit board and the main control board; the router module is fixed on the upper side of the switch circuit board, and an internal circulation unit with an air outlet facing downward is arranged above the router module, and the surroundings of the internal circulation unit are air inlet ends, and the internal circulation unit is fixedly installed on the top wall of the equipment shell;

[0031] The red light camera is surrounded by a metal enclosure wall, isolating the first white light camera module and the second white light camera module outside the metal enclosure wall; the upper end of the red light camera housing is heat-conductingly matched with the top wall of the device housing through a heat conducting block;

[0032] A connecting passage is formed between the switch circuit board and the metal enclosure wall, and a first side passage and a second side passage are formed between the two sides of the switch circuit board and the inner wall of the device housing respectively; the upper space of the switch circuit board is connected to the heat dissipation cavity through the connecting passage, the first side passage and the second side passage respectively;

[0033] A ring-shaped channel is formed between the heat-conducting block and the metal enclosure wall, and the space enclosed by the metal enclosure wall is connected to the inner cavity of the device housing through the ring-shaped channel;

[0034] Based on the above physical structure, a simulated three-dimensional physical model of the field temperature measurement equipment is established, and boundary conditions are defined for the simulated three-dimensional physical model of the field temperature measurement equipment, and material properties of the field temperature measurement equipment are defined.

[0035] Furthermore, a heat dissipation analysis optimization method of a field temperature measurement device based on CFD simulation analysis is provided. From the temperature cloud map of the field temperature measurement device obtained by S4 and S5, it can be seen that the main control board has a local high temperature zone, and the local high temperature zone is close to the central area of ​​the main control board; if the temperature of the local high temperature zone has exceeded the maximum temperature of the normal operation of the equipment, then an optimized design is required.

[0036] Further, based on the conclusion of step S5, the structure and boundary conditions of the simulated three-dimensional physical model of the field temperature measurement equipment in step S2 are optimized as follows: the internal circulation unit above the switch circuit board is moved to above the connecting channel between the switch circuit board and the metal enclosure wall.

[0037] Further, after completion, S3, S4, and S5 are repeated, and the optimization is completed when the local maximum temperature of the field temperature measurement equipment reaches the temperature range of normal operation of the equipment.

[0038] Beneficial effect: The present invention provides a heat dissipation analysis optimization method for a field temperature measurement device based on CFD simulation analysis. By establishing a heat generation model of the field temperature measurement device and a simulated three-dimensional physical model of the field temperature measurement device, a thermal simulation analysis is performed on the simulated three-dimensional physical model through ANSYS / Icepak electronic thermal analysis software to obtain the temperature distribution and change or temperature cloud map of the field temperature measurement device. Based on the installation position of the electronic device, an optimization design is performed on the location where the heat dissipation device or the heat dissipation structure is installed, so that when the field temperature measurement device is in steady-state operation, the temperature of the local high-temperature zone in the field temperature measurement device reaches the temperature range of normal operation of the device; the field temperature measurement device can operate normally and stably through the optimization method, and the safety of the field temperature measurement device is guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A flow chart of the heat dissipation analysis and optimization method for field temperature measurement equipment;

[0040] Figure 2 A three-dimensional image of the field temperature measurement device with the top shell removed;

[0041] Figure 3 A top view of the field temperature measurement device with the top shell removed;

[0042] Figure 4 It is a side view of the field temperature measurement equipment;

[0043] Figure 5 This is a bottom view of the bottom shell of the field temperature measurement equipment;

[0044] Figure 6 is the structural diagram of the heat sink;

[0045] Figure 7 This is the temperature cloud diagram of the device shell without heat sink;

[0046] Figure 8 The temperature cloud diagram of the equipment shell with heat sink installed;

[0047] Fig. 9 To optimize the design of the temperature cloud map of the inner cavity of the front field temperature measurement equipment;

[0048] Fig.10 To optimize the design of the temperature cloud map of the inner cavity of the field temperature measurement equipment;

[0049] Fig.11 This is a physical picture of the field temperature measurement equipment. DETAILED DESCRIPTION

[0050] The present invention will be further described below in conjunction with the accompanying drawings.

[0051] like Figure 1 As shown, a heat dissipation analysis and optimization method of a field temperature measurement device based on CFD simulation analysis includes the following steps:

[0052] S1. Based on the constructed mathematical model of heat transfer of the field temperature measurement equipment, a heat generation model of the field temperature measurement equipment is established;

[0053] S2. establishing a simulated three-dimensional physical model of the field temperature measurement device based on the geometric shape of the field temperature measurement device, defining boundary conditions for the simulated three-dimensional physical model of the field temperature measurement device, and defining material properties of the field temperature measurement device;

[0054] S3, performing elemental grid division on the calculation area of ​​the simulated three-dimensional physical model of the field temperature measurement equipment, and checking whether the grid division meets the solution standard, otherwise re-gridding is performed, and if yes, proceeding to the next step;

[0055] S4. Simulate and solve the simulated three-dimensional physical model of the field temperature measurement equipment, perform thermal simulation analysis through ANSYS / Icepak electronic thermal analysis software, and obtain the temperature distribution and change when the field temperature measurement equipment reaches a thermal steady state;

[0056] S5. According to the temperature cloud map obtained in S4, the local maximum temperature and distribution area in the field temperature measurement equipment are obtained;

[0057] S6. According to the simulated three-dimensional physical model, the boundary conditions of the model and the material properties, a physical field temperature measurement device is built and operated according to the set conditions to detect whether the error between the actual temperature and the simulation analysis in S4 is within an acceptable range. If yes, proceed to the next step;

[0058] S7. Based on the conclusion of S5, optimize the model and boundary conditions of S2;

[0059] S8. Execute S3-S7 until the local maximum temperature of the optimized field temperature measurement device reaches the temperature range of normal operation of the device.

[0060] Based on the continuity equation, momentum conservation equation, energy conservation equation and the constructed mathematical model of heat transfer of field temperature measurement equipment, a heat generation model of field temperature measurement equipment is established; the continuity equation is set based on the law of conservation of mass, which means that the increase in mass in the microelement per unit time is equal to the net mass flowing into the microelement in the same time; the calculation process is as follows:

[0061]

[0062] And the vector expression is:

[0063]

[0064] Where ρ is the fluid density in kg / m 3 ; t is time, unit is s; u, v, w represent the components of velocity in x, y, z directions, m / s respectively;

[0065] The momentum conservation equation is set to:

[0066]

[0067] Where div() is the divergence in each direction, grad() is the gradient in each direction, U is the fluid velocity, ρ is the fluid density, μ is the fluid viscosity, and p is the pressure; S u , S v and S w are the generalized source terms in the x, y, and z directions respectively;

[0068] Energy conservation equation, the rate of increase of thermodynamic energy in the microelement is equal to the net heat flow into the microelement plus the work done by the volume force and surface force on the microelement. For incompressible fluid, the expression is:

[0069]

[0070] Where λ is the thermal conductivity of the fluid, S T is the viscous dissipation and T is the fluid temperature.

[0071] There are three main ways of heat transfer: heat conduction, heat convection, and heat radiation. In practical problems, these methods often do not appear alone, but appear simultaneously and alternately. The conduction process is a way for heat to transfer inside a substance, which relies on the physical principles of molecular motion. When a substance with a higher temperature comes into contact with a substance with a lower temperature, due to the temperature difference, heat is transferred from the higher temperature area to the lower temperature area.

[0072] The mathematical model of heat transfer of the field temperature measurement equipment is constructed by obtaining a diffusion equation expressing temperature change through an expression of proportional relationship between the heat flow generated per unit area and the temperature gradient in the medium; the expression of proportional relationship is as follows:

[0073]

[0074] In the formula, Q is the heat flow, A is the surface area through which the heat flows, λ is the thermal conductivity of the fluid, and “-” indicates that the heat flows in the opposite temperature gradient;

[0075] When λ is constant and there is no heat source in the medium, the temperature change is expressed by the diffusion equation, which is as follows:

[0076]

[0077] Where c is the specific heat capacity and ρ is the density of the medium.

[0078] In order to simplify the complex three-dimensional heat conduction problem, the diffusion equation expressing the temperature change is converted from a three-dimensional formula to a one-dimensional formula, and the one-dimensional temperature gradient expression is obtained. The expression is substituted into the proportional relationship expression to obtain the heat flow formula; it is approximately the heat conduction of the heat in the shell of the field temperature measurement equipment, the temperature is constant and the temperature gradient is constant, and the one-dimensional temperature gradient expression is as follows:

[0079]

[0080] In the formula, D is the thickness of the device shell, T1 is the temperature of the device cavity, and T2 is the ambient temperature of the field temperature measurement device;

[0081] Substituting the one-dimensional temperature gradient expression into the proportional relationship expression yields the heat flow formula:

[0082]

[0083] Divide the shell of the field temperature measurement equipment into several infinitely thin and uniform outer shell layers to form a complex heat conduction network, and obtain the heat flow formula for each layer;

[0084] The heat flow formula for the nth layer is:

[0085]

[0086] Where, T n 、T n+1 Represent the temperatures of the two layers of n layers,

[0087] When the heat flux through each layer is equal, that is, Q n =Q, the heat flow formula for the nth layer is as follows:

[0088]

[0089] According to the temperature T of the external environment of the field temperature measuring equipment shell n and T N , the heat flow formula of the shell of the field temperature measurement equipment is obtained by the recursive method, and simplified, and the simplified formula is used as the mathematical model of heat transfer of the field temperature measurement equipment; the heat flow formula of the shell of the field temperature measurement equipment is as follows:

[0090]

[0091] Introducing the thermal resistance of the shell, the simplified formula is:

[0092]

[0093] A / r is expressed as thermal resistance 1 / R, showing the ability to hinder heat conduction. Then the heat flow through the shell of the field temperature measurement equipment is approximately proportional to the temperature difference on both sides of the shell, and the mathematical model of heat transfer of the field temperature measurement equipment is obtained;

[0094]

[0095] like Figure 2-3 As shown, in S2, the physical structure of the field temperature measurement device includes a sealed device housing 1, and the device housing 1 includes a main control board 2, a red light camera 3, a red light camera control board 10, a switch circuit board 4, a router module 5, a first white light camera module 8 and a second white light camera module 9; the red light camera 3 is installed on the red light camera control board 10, and the first white light camera module 8 and the second white light camera module 9 are respectively arranged on both sides of the red light camera 3; the main control board 2 is horizontally fixed to the bottom of the inner wall of the device housing 1, and the main control board 2 is located on the side of the red light camera 3 away from the lens end; the switch circuit board 4 is parallel to the top of the main control board 2, and a heat dissipation cavity 22 is formed between the switch circuit board 4 and the main control board 2; the router module 5 is fixed on the upper side of the switch circuit board 4, and an internal circulation unit 11 with an air outlet facing downward is arranged above the router module 5, and the four sides of the internal circulation unit 11 are air inlet ends, and the internal circulation unit 11 is fixedly mounted on the top wall of the device housing 1. The main control board is fixed 20mm from the lower shell, and other small-sized and low-power consumption components are evenly distributed on the entire main board. The switch module is fixed 30cm above the main control board.

[0096] The size of the device housing 1 is 340mm×212mm×194mm, and the device housing 1 is made of aluminum alloy with a thermal conductivity of λ=120W / (m·K); the power consumption of the field temperature measurement device is 36W, the mass of the field temperature measurement device is 8.8kg, the working temperature is -30℃-60℃, the effective working distance is 10-80m, and the voltage is DC 12V. The switch circuit board 4 adopts the switch LX-IS5011, with a single power consumption of 0.8W, a total power consumption of 0.8W, and an operating temperature of -40℃~85℃; the router module 5 adopts the router LW-IP301-ELSKY, with a single power consumption of 3.4W and a total power consumption of 3.4W; the main control machine 2 adopts NUC600 (7500U), with a single power consumption of 30W, a total power consumption of 30W, and an operating temperature of -20℃~60℃. The operating temperature of the red light camera in the device housing 1 is 65.89°C, the electronic devices in the device housing 1 work normally, the inner cavity temperature in the device housing 1 is 67.782°C, and the operating temperature of the main control board 2 in the device housing 1 is 76.38°C. Therefore, an internal circulation unit 11 is provided in the device housing 1, and the internal circulation unit 11 can be a fan. The rotation of the fan installed inside the device increases the air flow inside the device housing 1 to enhance the heat dissipation of the device; when the fan rotates, it accelerates the air flow in the inner cavity of the device, speeds up the heat conduction of the air, helps to alleviate the uneven temperature distribution in the inner cavity of the device, and diffuses the heat in the inner cavity of the device to the vicinity of the device housing. The heat in the inner cavity of the device is brought to the external environment through the housing to achieve effective heat dissipation.

[0097] like Figure 2-4As shown, the red light camera 3 is surrounded by a metal enclosure wall 21, isolating the first white light camera module 8 and the second white light camera module 9 on the outside of the metal enclosure wall 21; the upper end of the red light camera 3 shell is heat-conducted to the top wall of the device shell 1 through a heat-conducting block 33; the first white light camera module 8 includes a first white light camera 81 and a first white light camera control board 82; the second white light camera module 9 includes a second white light camera 91 and a second white light camera control board 92. The heat-conducting block 33 is thermally connected to the device shell 1 through thermal grease, and the heat-conducting block 33 can be an aluminum block; by adding an aluminum block between the red light camera 3 and the device shell 1 for heat conduction, the heat generated by the red light camera 3 is transferred to the device shell 1 through the aluminum block, and then heat is exchanged with the external environment through natural convection. The metal enclosure wall 21 isolates the first white light camera module 8 and the second white light camera module 9 outside the metal enclosure wall 21. Since the red light camera 3, the first white light camera module 8 and the second white light camera module 9 will generate heat when working, the metal enclosure wall 21 is provided to isolate the heat generated by the first white light camera module 8 and the second white light camera module 9 from affecting the temperature of the red light camera 3, thereby preventing the temperature of the red light camera 3 from rising and ensuring the normal operation of the red light camera 3; at the same time, it can also isolate the heat generated by the red light camera 3 from affecting the temperature of the first white light camera module 8 and the second white light camera module 9.

[0098] like Figure 3-4 As shown, the lenses of the first white light camera 81, the second white light camera 91 and the red light camera 3 are oriented in the same direction; a camera panel 7 is provided on the inner wall of the device housing 1 on the side facing the lens of the red light camera, and holes covered with transparent material are provided at positions on the camera panel 7 corresponding to the lenses of the first white light camera, the second white light camera and the red light camera, so that the airtightness of the device housing 1 is ensured while ensuring that the red light camera and the two white light cameras can capture images; a plug panel 6 is provided on one side of the device housing 1 opposite to the camera panel 7, and the plug port of the switch circuit board 4 is provided on the plug panel 6, and the end connected to the external device line is electrically connected to the plug port of the switch circuit board 4.

[0099] like Figure 2-4 As shown, a connecting passage 23 is formed between the switch circuit board 4 and the metal enclosure wall 21, and a first side passage 41 and a second side passage 42 are formed between the two sides of the switch circuit board 4 and the inner wall of the device housing 1; the upper space of the switch circuit board 4 is connected to the heat dissipation cavity 22 through the connecting passage 23, the first side passage 41 and the second side passage 42. A ring-shaped passage 24 is formed between the heat conducting block 33 and the metal enclosure wall 21, and the space enclosed by the metal enclosure wall 21 is connected to the inner cavity of the device housing 1 through the ring-shaped passage 24.

[0100] When the internal circulation fan in the device housing 1 is started, the fan rotates, and the airflow blown by the fan first blows to the space above the switch circuit board 4, and then the airflow diffuses from the upper surface of the switch circuit board 4 to the surroundings, dispersing the heat generated by the switch circuit board 4 and the router module 5, thereby reducing the temperature near the switch circuit board 4 and the router module 5. At this time, the airflow is divided into two paths. Most of the airflow is blown toward the inner side of the metal enclosure wall 21 through one side of the annular channel 24, and the airflow is blown toward the gap space between the red light camera 3 and the metal enclosure wall 21. The airflow comes out from the other side of the annular channel 24, and takes away the heat generated by the red light camera 3, thereby reducing the temperature of the red light camera 3; another small part of the airflow is blown toward the heat dissipation cavity 22 through the connecting channel 23, the first side channel 41 and the second side channel 42. The airflow is blown into the heat dissipation cavity 22. After the airflow touches the panel of the main control board or the inner wall of the device shell, it comes out again through the connecting channel 23, the first side channel 41 and the second side channel 42, and takes away the heat generated by the main control board 2, thereby reducing the temperature of the main control board; and the heat brought out by the airflow gradually approaches the device shell 1, and the heat is transferred to the outside of the device shell through the device shell, and then diffused into the environment.

[0101] like Figure 4 As shown, the main control board 2 transfers heat through the heat-conducting structure 14 to cooperate with the bottom of the inner wall of the equipment shell 1, and the heat-conducting structure 14 includes a temperature-averaging plate and a heat pipe; the heat input end of the sealed shell in the temperature-averaging plate transfers heat to cooperate with the bottom of the main control board 2, the heat output end of the sealed shell in the temperature-averaging plate transfers heat to cooperate with the evaporation section of the tube shell in the heat pipe, and the condensation section of the tube shell in the heat pipe transfers heat to cooperate with the bottom of the inner wall of the equipment shell 1; the temperature-averaging plate can be of a size of 100*100*3mm, with a thermal conductivity of 10000W / (m*K), and the thermal conductivity of the heat pipe is 20000W / (m*K).

[0102] The temperature spreader is a heat pipe technology distributed on a two-dimensional plane for heat dissipation. It achieves efficient heat conduction through a phase change heat dissipation mechanism and is widely used in the field of heat dissipation of electronic products. The temperature spreader consists of a closed shell, a capillary structure layer on the surface of the shell, and a working medium. In the heating zone, which is the heat input end or evaporation end, the working medium evaporates from liquid to gas, and the gas is quickly distributed in the cavity. Then in the cooling zone, which is the heat output end or condensation end, it condenses into liquid and returns to the heating zone through capillary action. This cycle effectively transfers heat. Although the heat spreader itself cannot store heat energy, its main advantage is that its heat transfer performance on a plane far exceeds that of general metal materials; it has an equivalent thermal conductivity of more than 20000W / (m*K), and the thickness can be as small as 3mm, which is almost equivalent to the thickness of the metal cavity wall, so it does not take up too much extra space. The temperature equalizer is embedded between the heat source and the heat pipe. This layout allows the heat generated by the heat source to be first directed to the temperature equalizer. Due to its two-dimensional structure, this thermally conductive material transfers heat with extremely high efficiency. This heat transfer method not only ensures that the heat can be distributed efficiently and evenly, but also ensures that the phase change material can fully absorb and utilize this energy, further enhancing the effectiveness of the phase change material at the heat source, thereby improving the efficiency of the entire cooling system.

[0103] The heat pipe transfers a large amount of heat over a long distance through a very small cross-sectional area without relying on external power; the heat pipe consists of three main parts: the tube shell, the wick and the end cap; the tube shell is the main structure of the heat pipe; the wick is a special capillary porous material that can absorb heat and transfer it to the surrounding environment or other heat transfer media; the end cap is responsible for sealing and protecting the working liquid in the tube to ensure that the heat can be effectively transferred. The working principle of the heat pipe is to use the negative pressure formed inside to drive the working liquid to flow in the tube. In this way, it can quickly transfer heat from one area, the evaporation section, to another area, the cooling section, to achieve heat redistribution. When one section of the heat pipe contacts the heat source, i.e., the heat output end of the temperature equalizer, the capillary wick inside it begins to work, and the liquid gradually evaporates until it is completely vaporized in the process; then, the heat carried by the steam migrates to the other end of the heat pipe at an extremely high speed, and the released heat is converted into liquid, which, driven by capillary force, flows along the porous material to the evaporation part, thereby continuously and rapidly transporting the temperature of the heat output end of the temperature equalizer to the bottom of the inner wall of the device housing 1 in a continuous cycle.

[0104] like Figure 5-6As shown, a heat sink 31 is fixedly installed at the bottom of the device housing 1, and the heat sink 31 includes a substrate and a plurality of heat sink ribs; one side of the substrate is fixed to the bottom of the outer wall of the device housing 1 by a heat conductive material 32, and the other side of the substrate is fixedly provided with a plurality of heat sink ribs. The plurality of heat sink ribs are parallel to each other, and the spacing between the plurality of heat sink ribs is equal; the length direction of the heat sink ribs is consistent with the length direction of the device housing 1. The heat sink 31 mainly considers multiple factors such as material selection, thickness, shape, and the degree of matching with the device housing to achieve the best heat dissipation effect. The heat dissipation efficiency of the heat sink 31 is mainly reflected by the thermal resistance of the heat sink. When calculating the thermal resistance of the heat sink, the model of the heat sink is first simplified, and an equivalent thermal resistance model is created.

[0105] like Figure 6 As shown, the thermal resistance of the heat sink 31 mainly includes the conduction thermal resistance of the substrate, the conduction thermal resistance of the heat sink fins, and the convection thermal resistance of the fins; the total thermal resistance calculation process of the heat sink 31 is as follows:

[0106]

[0107] In the formula, R th,b is the thermal conduction resistance of the substrate, R th,fin is the conduction thermal resistance of the heat sink fin, R th,A is the convection thermal resistance of the heat sink fin;

[0108] The calculation process of the convection thermal resistance of the heat sink fin is as follows:

[0109]

[0110] Where Hb is the height of the heat sink, m; L is the length of the heat sink, m; h is the convection heat transfer coefficient between the heat sink and the air, W / m 2 K; n is the number of heat sink fins; the conduction calculation process of the substrate is as follows:

[0111]

[0112] Where b is the thickness of the substrate, m; W is the width of the heat sink, m; K is the thermal conductivity of the heat sink material, W / m℃; the calculation process of the conduction thermal resistance of the heat sink fin is as follows:

[0113]

[0114] The total thermal resistance of the heat sink is expressed as:

[0115]

[0116] The total thermal resistance of the heat sink is mainly affected by the dimensional parameters of the heat sink. By optimizing the dimensional parameters of the heat sink, the total thermal resistance of the heat sink can be reduced, thereby improving the heat dissipation efficiency. Based on the calculation formula of the total thermal resistance of the heat sink, the material and size that minimize the total thermal resistance of the heat sink are selected. The heat sink is made of aluminum alloy, the height of the heat sink is selected as 30mm, the width of the heat sink is selected as 212mm, and the length of the heat sink is selected as 340mm. The height of the heat sink fin is 20mm, the thickness of the heat sink fin is 1.2mm, the number of heat sink fins is 32, and the thickness of the substrate is 10mm. Analysis of the influence of the thickness of the heat sink fins: As the thickness of the heat sink fins increases, there are two sides to the heat transfer. On the one hand, increasing the thickness can enhance the ability of the heat source to transfer heat to the heat sink, which helps to dissipate heat. On the other hand, as the thickness of the heat sink fins increases, the flow area through which the cooling air flows will decrease, resulting in an increase in flow resistance and a decrease in wind speed, which is not conducive to heat dissipation. At the same time, increasing the thickness may lead to a decrease in the number of heat sink fins, which means a decrease in heat exchange area, which is not conducive to heat dissipation. Therefore, there is a balance point. Before this point, increasing the thickness of the heat sink is beneficial to improving the heat dissipation performance, but after this point, too thick a heat sink will reduce the heat dissipation efficiency. The thickness of the heat sink fin is selected to be 1.2 mm; the number of heat sink fins is n=26.

[0117] When the field temperature measurement device is in normal operation, thermal simulation is performed on the bottom of the device housing without the heat sink 31 and the bottom of the device housing with the heat sink; a temperature cloud map of the device housing without the heat sink and a temperature cloud map of the device housing with the heat sink are obtained, such as Figure 7-8 As shown; it can be seen that the heat of the device casing is successfully transferred from the device casing to the heat sink, the temperature is lower than when no radiator is installed, and the temperature distribution on the heat sink is more uniform, achieving the purpose of good heat dissipation.

[0118] The first external fan 12 and the second external fan 13 are evenly arranged on one side of the heat dissipation fins in the heat sink 31. The two fans outside the device housing 1 accelerate the air flow speed of the device surrounding environment, so that the heat conducted to the device housing 1 is transferred to the external environment as quickly as possible.

[0119] Based on the above physical structure, a simulated three-dimensional physical model of the field temperature measurement equipment is established, and the boundary conditions and material properties of the simulated three-dimensional physical model of the field temperature measurement equipment are defined. The model boundary conditions are set for calculation, and the Steady numerical type is selected; according to the calculated Reynolds and Peclet numbers, it can be determined to be a turbulent model, and the selected model is Zeroequation; the field temperature measurement equipment is forced air cooling, and the temperature and fluid need to be calculated. The external environment temperature is set to 26.5℃, the default fluid is air, and the default material is aluminum alloy; Gravityvector is set to on, because there is convection heat dissipation in the device, so the effect of gravity acceleration on the device must be considered; set the number of iterations to 200 steps; because in forced air cooling, the effect of radiation heat is much smaller than that of convection heat, so the radiation coefficient can be ignored in the calculation in this article.

[0120] Before simulation, the calculation area of ​​the thermal analysis model of the field temperature measurement equipment is divided into elemental grids. The quality and precision of the grid division will have a certain impact on the calculation speed and the accuracy of the simulation results; the better the grid quality and the denser the grid division, the higher the calculation accuracy, but the number of grids will also increase accordingly, resulting in an increase in the amount of calculation. Therefore, the grid division generally improves the grid quality as much as possible under the premise of ensuring that the calculation can be completed effectively. Icepak can automatically generate grids by setting the grid type including structured and unstructured grids, parameters, maximum length and other parameters. The grid is selected according to the hexahedron to optimize the grid division, which can reduce the number of grids, and the grids do not cross vertically, which is suitable for various initial geometric shapes such as polygons and columns; considering that some structures of the model contain a large number of small sizes, the heat sink, the fan of the equipment cavity and the shell, and the main control board are set as an Assembly for grid refinement. Assembly combines multiple physical models to construct a spatial structure or multiple local spatial regions, which is convenient for fine encryption of device models with complex shapes and unique designs, and can reduce the number of grid divisions. The total number of grids generated is 970,000. It also verifies whether the grid division meets the solution standard. Otherwise, it re-divides the grid, and proceeds to the next step. The conditions for checking whether the grid division meets the solution standard are as follows:

[0121] Cu>0.15

[0122] V>e×10 -12

[0123] Tor>0.02

[0124] Where Cu is the surface alignment rate, V is the volume, and Tor is the twist rate.

[0125] A heat dissipation analysis and optimization method for a field temperature measurement device based on CFD simulation analysis, wherein the temperature cloud map of the field temperature measurement device obtained by S4 and S5 is as follows: Fig. 9 As shown in the figure, when the ambient temperature is 26.5℃ and the field temperature measurement equipment reaches a steady state, the maximum temperatures of the inner cavity of the field temperature measurement equipment, the red light camera and the main control board are 67.782℃, 65.890℃ and 76.383℃ respectively; it can be seen that the main control board has a local high temperature area, and the local high temperature area is close to the center of the main control board; the temperature of the local high temperature area has exceeded the maximum temperature of the normal operation of the equipment, and the design needs to be optimized; the local maximum temperature does not exceed the maximum temperature of the normal operation of the equipment, and is within the temperature range of the normal operation of the equipment, then the optimization design is completed. The temperature range for normal operation of the equipment can be set to -30℃~60℃, and it is set according to the actual use of the equipment in practice.

[0126] In said S6, according to the simulated three-dimensional physical model, the boundary conditions of the model and the material properties, a physical field temperature measurement device is built and operated according to the set conditions to detect whether the error between its actual temperature and the simulation analysis in S4 is within an acceptable range; building a physical field temperature measurement device, such as Fig.11 As shown, and run according to the set conditions, various temperature detection points are set in the field temperature measurement equipment, mainly detecting the inner cavity of the field temperature measurement equipment, the red light camera and the main control board; a comparison table of the simulated analysis temperature and the actual detection temperature is obtained, as shown in Table 1 below;

[0127] Table 1 Comparison of simulation analysis temperature and actual detection temperature

[0128]

[0129] It can be seen from Table 1 that under the same ambient temperature, there is a local difference between the steady-state temperature of the equipment detection point measured in the experiment and the steady-state temperature of the equipment detection point after simulation, and the simulated temperature is slightly higher than the temperature measured in the experiment. The difference between the simulated temperature and the measured temperature is within 5°C, and the relative error is controlled within 10%, which proves that the established simulation model is accurate and effective. Through the analysis of the temperature data of the equipment cavity and the shell measured in the experiment, the temperature of the equipment cavity is about 28°C higher than that of the shell in the steady state, indicating that the heat in the equipment cavity accumulates and the heat is not dissipated through the equipment shell in time. Through analysis, it can be seen that the reason for the error in the steady-state temperature data obtained by the experiment and the simulation is that when simplifying the equipment model, in order to facilitate the simulation calculation, the small-sized grooves on the surface of the equipment are removed, which is equivalent to reducing the effective heat dissipation area of ​​the equipment surface, resulting in a small increase in the temperature of the monitoring point compared with the experimental measurement. Second, the power of the components inside the equipment is different, and the temperature of the inner cavity is unevenly distributed. The position of the monitoring point during the experiment may have a certain error. In addition, the convective heat transfer coefficient used in the simulation in this article is a constant, while the actual convective heat transfer coefficient may change with changes in the environment and temperature.

[0130] When the ambient temperature is 26.5℃, the maximum temperature of the red light camera metal shell is 50.037℃ when the field temperature measurement equipment reaches a steady state, and the inner cavity temperature is higher than the maximum temperature of the camera. Since the working temperature of industrial cameras is -5℃ to 45℃, it means that when the ambient temperature is 26.5℃, the camera may have exceeded the working temperature range. Considering the use requirements of the field temperature measurement equipment, as the ambient temperature increases, the temperature of each part of the equipment will continue to rise when it is working, exceeding its working temperature. Therefore, it is necessary to optimize the structure and boundary conditions of the field temperature measurement equipment to improve the heat dissipation efficiency of the equipment cavity.

[0131] According to the conclusion of step S5, the structure and boundary conditions of the simulated three-dimensional physical model of the field temperature measurement equipment of S2 are optimized as follows: the local high temperature area is in the central area close to the main control board, and the temperature of the local high temperature area has exceeded the maximum temperature of the normal operation of the equipment; because the internal circulation unit 11, that is, the fan is located above the switch circuit board 4, the switch circuit board blocks the straight path of the fan directly blowing the airflow to the main control board, so when the airflow contacts the switch circuit board, most of the airflow will diffuse to the surroundings at the same height as the panel of the switch circuit board; only a small part of the airflow is blown to the diffuser through the connecting aisle 23, the first side aisle 41 and the second side aisle 42 The heat chamber 22, so the airflow can only take away the heat generated by the main control board. At the same time, because the airflow cannot smoothly take away the heat after entering the heat dissipation chamber, the airflow with heat can only return to the original path and come out again through the connecting passage 23, the first side passage 41 and the second side passage 42. However, the airflow with heat and the airflow blown out by the fan will meet or collide in the connecting passage 23, the first side passage 41 and the second side passage 42. A part of the airflow with heat will be blocked in the heat dissipation chamber and cannot go out, and a part of the airflow with heat will be trapped in the heat dissipation chamber, which will cause the temperature of the heat dissipation chamber 22 to gradually increase, and it is impossible to effectively dissipate heat, which may eventually cause damage to the main control board. Therefore, an optimized design is made to move the internal circulation unit 11 above the switch circuit board 4 to the top of the connecting passage 23 between the switch circuit board 4 and the metal enclosure wall 21.

[0132] After the internal circulation unit 11 is moved and started, the airflow blown by the fan is downward. When it contacts the switch circuit board 4 and the metal enclosure wall 21, the airflow is divided into three airflows. One part of the airflow is blown to the inner side of the metal enclosure wall 21 through one side of the annular channel 24, and the airflow is blown to the gap space between the red light camera 3 and the metal enclosure wall 21. The airflow comes out from the other side of the annular channel 24, takes away the heat generated by the red light camera 3, and reduces the temperature of the red light camera 3; one part of the airflow will blow to the switch circuit board and the router module, take away the heat of the switch circuit board and the router module and blow it out from the top wall of the device housing 1; the last part of the airflow will directly blow to the heat dissipation cavity 22 through the connecting channel 23, and the airflow can take away the heat generated by the main control board 2 and can be brought out by the first side aisle 41 and the second side aisle 42, and no airflow with heat will accumulate in the heat dissipation cavity 22, thereby effectively reducing the temperature of the main control board.

[0133] After completion, repeat S3, S4, and S5 to obtain the temperature cloud map of the field temperature measurement equipment, such as Fig.10As shown, under the ambient temperature of 26.5℃, when the field temperature measurement equipment reaches a steady state, the maximum temperatures of the inner cavity of the field temperature measurement equipment, the red light camera and the main control board are 49.9527℃, 47.6614℃ and 53.2033℃ respectively; when the equipment reaches a steady state, the temperatures of the inner cavity of the equipment, the red light camera and the main control board decrease by 15.937℃, 20.121℃ and 23.744℃, and the local maximum temperature of the field temperature measurement equipment reaches the temperature range of normal operation of the equipment, completing the optimization and improving the heat transfer efficiency of the inner cavity of the equipment.

[0134] Example

[0135] The optimized design of the structure and boundary conditions of the simulated three-dimensional physical model of the field temperature measurement equipment in S7 can be to optimize the design of the switch circuit board and router module. When possible, holes are opened at the positions of the switch circuit board and router module corresponding to the local high temperature area of ​​the main control board while ensuring that the circuit board can operate normally, so that the airflow blown out of the internal circulation unit can blow directly in a straight line to the local high temperature area of ​​the main control board. Alternatively, the switch circuit board and router module can be redesigned, and air holes are reserved at the positions corresponding to the local high temperature area of ​​the main control board while ensuring that the circuit board can operate normally, so that the airflow blown out of the internal circulation unit can blow directly in a straight line to the local high temperature area of ​​the main control board.

[0136] The above is only a description of the preferred embodiments of the present invention. Ordinary technicians in this technical field can make several modifications and optimizations based on the above disclosure without departing from the above basic principles. These improvements and optimizations should be regarded as the understood protection scope of the present invention.

Claims

1. A heat dissipation analysis and optimization method for field temperature measurement equipment based on CFD simulation analysis, characterized in that: The following steps are involved: S1. Based on the constructed mathematical model of heat transfer of the field temperature measurement equipment, a heat generation model of the field temperature measurement equipment is established; S2. establishing a simulated three-dimensional physical model of the field temperature measurement device based on the geometric shape of the field temperature measurement device, defining boundary conditions for the simulated three-dimensional physical model of the field temperature measurement device, and defining material properties of the field temperature measurement device; S3, performing elemental grid division on the calculation area of ​​the simulated three-dimensional physical model of the field temperature measurement equipment, and checking whether the grid division meets the solution standard, otherwise re-gridding is performed, and if yes, proceeding to the next step; S4. Simulate and solve the simulated three-dimensional physical model of the field temperature measurement device to obtain the distribution and change of the temperature when the field temperature measurement device reaches a thermal steady state; S5. According to the temperature cloud map obtained in S4, the local maximum temperature and distribution area in the field temperature measurement equipment are obtained; S6. According to the simulated three-dimensional physical model, the boundary conditions of the model and the material properties, a physical field temperature measurement device is built and operated according to the set conditions to detect whether the error between the actual temperature and the simulation analysis in S4 is within an acceptable range. If yes, proceed to the next step; S7. Based on the conclusion of S5, optimize the model and boundary conditions of S2; S8. Execute S3-S7 until the local maximum temperature of the optimized field temperature measurement device reaches the temperature range of normal operation of the device.

2. The heat dissipation analysis and optimization method of a field temperature measurement device based on CFD simulation analysis according to claim 1 is characterized in that: The mathematical model of heat transfer of the field temperature measurement equipment is constructed by expressing the proportional relationship between the heat flow generated per unit area and the temperature gradient in the medium. The proportional relationship expression is as follows: In the formula, Q is the heat flow, A is the surface area through which the heat flows, λ is the thermal conductivity of the fluid, and "-" means that the heat flows in the opposite temperature gradient; When λ is constant and there is no heat source in the medium, the temperature change is expressed by the diffusion equation, which is as follows: Where c is the specific heat capacity and ρ is the density of the medium.

3. The heat dissipation analysis and optimization method of a field temperature measurement device based on CFD simulation analysis according to claim 2 is characterized in that: The diffusion equation expressing the temperature change is converted from a three-dimensional formula to a one-dimensional formula to obtain a one-dimensional temperature gradient expression, and the expression is substituted into the proportional relationship expression to obtain the heat flow formula; the temperature remains unchanged and the temperature gradient remains constant, and the one-dimensional temperature gradient expression is as follows: In the formula, D is the thickness of the device shell, T1 is the temperature of the device cavity, and T2 is the ambient temperature of the field temperature measurement device. Substituting the one-dimensional temperature gradient expression into the proportional relationship expression, the heat flow formula is obtained:

4. The heat dissipation analysis and optimization method of a field temperature measurement device based on CFD simulation analysis according to claim 2 is characterized in that: The shell of the field temperature measurement equipment is divided into several infinitely thin and uniform outer shell layers, and the heat flow formula for each layer is obtained; the heat flow formula for the nth layer is: Where, T n , T n+1 Represent the temperatures of the two layers of n layers, When the heat flux through each layer is equal, the heat flow formula for the nth layer is as follows:

5. The heat dissipation analysis and optimization method of field temperature measurement equipment based on CFD simulation analysis according to claim 2 is characterized in that: According to the temperature T of the external environment of the field temperature measuring equipment shell n and T N , the heat flow formula of the shell of the field temperature measurement equipment is obtained by the recursive method, and the thermal resistance of the shell is introduced to simplify it. The simplified formula is used as the mathematical model of heat transfer of the field temperature measurement equipment; 6. The heat dissipation analysis and optimization method of field temperature measurement equipment based on CFD simulation analysis according to claim 1 is characterized in that: In S2, the physical structure of the field temperature measurement device includes a sealed device housing (1), wherein the device housing (1) includes a main control board (2), a red light camera (3), a red light camera control board (10), a switch circuit board (4), a router module (5), a first white light camera module (8) and a second white light camera module (9); the red light camera (3) is mounted on the red light camera control board (10), and the first white light camera module (8) and the second white light camera module (9) are respectively arranged on both sides of the red light camera (3); the main control board (2) is horizontally fixed on the device The housing (1) is provided with a main control board (2) at the bottom of the inner wall, and the main control board (2) is located on a side of the red light camera (3) away from the lens end; the switch circuit board (4) is parallel to the upper side of the main control board (2), and a heat dissipation cavity (22) is formed between the switch circuit board (4) and the main control board (2); the router module (5) is fixed on the upper side of the switch circuit board (4), and an internal circulation unit (11) with an air outlet facing downward is arranged above the router module (5), and the surrounding areas of the internal circulation unit (11) are air inlet ends, and the internal circulation unit (11) is fixedly mounted on the top wall of the device housing (1); The red light camera (3) is surrounded by a metal enclosure wall (21), isolating the first white light camera module (8) and the second white light camera module (9) outside the metal enclosure wall (21); the upper end of the housing of the red light camera (3) conducts heat to the top wall of the housing of the matching device (1) through a heat conducting block (33); A connecting passage (23) is formed between the switch circuit board (4) and the metal enclosure wall (21); a first side passage (41) and a second side passage (42) are formed between the two sides of the switch circuit board (4) and the inner wall of the device housing (1); the upper space of the switch circuit board (4) is connected to the heat dissipation cavity (22) through the connecting passage (23), the first side passage (41) and the second side passage (42); An annular channel (24) is formed between the heat conducting block (33) and the metal enclosure wall (21), and the space enclosed by the metal enclosure wall (21) is connected to the inner cavity of the device housing (1) through the annular channel (24); Based on the above physical structure, a simulated three-dimensional physical model of the field temperature measurement equipment is established, and boundary conditions are defined for the simulated three-dimensional physical model of the field temperature measurement equipment, and material properties of the field temperature measurement equipment are defined.

7. The heat dissipation analysis and optimization method of field temperature measurement equipment based on CFD simulation analysis according to claim 6 is characterized in that: From the temperature cloud map of the field temperature measurement equipment obtained by S4 and S5, it can be seen that the main control board has a local high temperature area, and the local high temperature area is close to the central area of ​​the main control board; the temperature of the local high temperature area has exceeded the maximum temperature of the normal operation of the equipment, so optimization design is required.

8. The heat dissipation analysis and optimization method of field temperature measurement equipment based on CFD simulation analysis according to claim 7 is characterized in that: According to the conclusion of step S5, the structure and boundary conditions of the simulated three-dimensional physical model of the field temperature measurement equipment of step S2 are optimized as follows: the internal circulation unit (11) above the switch circuit board (4) is moved to above the connecting passage (23) between the switch circuit board (4) and the metal enclosure wall (21).

9. The heat dissipation analysis and optimization method of field temperature measurement equipment based on CFD simulation analysis according to claim 8, characterized in that: After completion, repeat S3, S4, and S5. When the local maximum temperature of the field temperature measurement equipment reaches the temperature range of normal operation of the equipment, the optimization is completed.

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