Printed circuit board type heat exchanger complete machine flow heat exchange simulation method, equipment and medium

Abstract

The invention discloses a printed circuit board heat exchanger complete machine flow heat exchange simulation method which comprises the following steps: setting physical property parameters of a cold channel working medium and a hot channel working medium, selecting a proper physical model, and constructing a single-channel flow resistance model; cold and hot channels are divided into cold and hot micro-channels and cold and hot runner systems, cold and hot micro-channel models are respectively constructed by the cold and hot micro-channels, and cold and hot runner system models are respectively constructed by the cold and hot runner systems; a plurality of heat exchange units are divided for the cold micro-channel geometric model and the hot micro-channel geometric model respectively, a three-dimensional flow heat exchange model is constructed for each heat exchange unit, and a heat exchanger axial temperature distribution one-dimensional model is constructed; simulating to obtain flow distribution calculation results of the cold and hot micro-channels; according to flow distribution calculation results of the cold and hot micro-channels and a temperature working condition table, performing simulation calculation on each three-dimensional flow heat exchange model to obtain outlet temperatures and heat exchange amounts of cold and heat treatment units of each heat exchange unit, further obtaining a convective heat exchange coefficient, and substituting the convective heat exchange coefficient into a heat exchanger axial temperature distribution one-dimensional model to obtain an axial temperature distribution condition of the heat exchanger.

Description

Technical Field

[0001] This invention relates to the field of heat exchanger simulation technology, and in particular to a method, equipment and medium for simulating the flow heat transfer of a printed circuit board type heat exchanger. Background Technology

[0002] Printed Circuit Heat Exchanger (PCHE) is a compact and efficient heat exchange device manufactured using precision etching and diffusion welding processes. Its core structure consists of multiple layers of thin metal plates etched with microchannels (typically 1-5mm in hydraulic diameter) that are diffusion welded together to form a plate stack. This, combined with inlet and outlet manifolds, distribution chambers, and other flow channel systems, constitutes the entire unit. Compared to traditional shell-and-tube and plate heat exchangers, PCHE has three core advantages: First, its compact structure and volumetric heat transfer coefficient of 2000-5000 W / (m³・K), 3-5 times that of traditional heat exchangers, significantly saving installation space. Second, its resistance to extreme conditions; by using high-temperature and high-pressure resistant materials such as Inconel 617, Haynes 282, and 316L stainless steel, it can operate in harsh environments with temperatures ≤800℃ and pressures ≤30MPa. Third, its high heat exchange efficiency; the strong disturbance effect and large specific surface area of ​​the microchannels significantly improve the overall heat exchange efficiency.

[0003] Based on the above advantages, PCHE has become a core and critical piece of equipment in cutting-edge fields such as supercritical CO2 Brayton cycle power generation, next-generation advanced nuclear energy, high-temperature hydrogen production and storage, and aerospace thermal management. The flow and heat transfer characteristics of PCHE are key indicators determining equipment performance, energy consumption, and operational safety, and the core value of its simulation technology is reflected in three main scenarios: Design verification: The heat exchange efficiency and pressure drop under the design conditions need to be quantified through simulation to ensure that the system integration requirements are met.

[0004] Structural optimization: It is necessary to analyze the impact of parameters such as channel size, ridge width, manifold diameter, and split chamber cone angle on flow heat transfer through simulation to achieve the design goal of "minimum metal mass + optimal performance".

[0005] Safety assessment: PCHEs under nuclear-grade and supercritical conditions need to simulate the flow and heat transfer response under transient load and accident conditions to verify that the equipment has no risk of local overheating or structural instability, and must meet the simulation accuracy requirements of different specifications.

[0006] Therefore, PCHE flow heat transfer simulation technology has become a core supporting tool for equipment research and development, design and engineering applications. Its accuracy, efficiency and versatility directly determine the upper limit of PCHE's application in extreme working conditions.

[0007] Currently, PCHE flow heat transfer simulation techniques typically employ the following methods: 1. This method primarily relies on engineering estimation. The core idea is to ignore the overall flow channel structure and calculate the heat transfer coefficient and pressure drop based solely on experimental correlations of single microchannels or small units, then extrapolate these empirical formulas to the entire system. The main drawbacks of this method are as follows: ① It completely ignores the influence of manifolds and distribution chambers on fluid distribution, assuming uniform flow rates in all microchannels. However, in actual engineering, variations in manifold diameter and irregular geometry of distribution chambers can lead to deviations in microchannel flow rates, resulting in inaccurate heat transfer efficiency calculations. ② It fails to consider the fluid-solid conjugate heat transfer effect, assuming uniform wall temperature. However, PCHEs often exhibit high temperature differences, leading to distorted heat transfer coefficient predictions. ③ It is only applicable to steady-state conditions with straight channels and conventional fluids, and cannot adapt to complex scenarios such as sawtooth channels, supercritical fluids, and phase changes.

[0008] 2. A local fine-scale modeling method is adopted, which extracts small-sized units from the core heat exchange zone of the PCHE as feature models, constructs the complete microchannel geometry, and performs fine mesh generation to simulate local flow and heat transfer details. This method can accurately capture local characteristics such as turbulence and near-wall temperature gradients within the microchannel, but it has the following drawbacks: ① Scale limitation: it can only simulate local units and cannot reflect the uneven fluid distribution in the overall manifold-microchannel system, leading to the contradiction of "high local accuracy but biased overall prediction"; ② Distorted boundary condition assumptions: the inlet parameters of the local model need to be manually set, resulting in significant differences from the actual flow state of the entire system, causing the simulation results to deviate from engineering reality.

[0009] 3. Full-size detailed modeling of the entire system: Based on the PCHE system drawings, a full-size geometric model including the manifold, shunt chamber, and all microchannel arrays is constructed. A unified and fine mesh is used. The disadvantages of this method are as follows: ① The contradiction of scale coupling is extremely prominent. The length of the PCHE system is usually 1-3 meters, and the number of microchannels reaches thousands to tens of thousands. The full-size model has a huge number of meshes, which requires a very large amount of computing resources, making it completely infeasible for engineering applications; ② The mesh quality is difficult to control. The scale difference between the microchannel fillets and the manifold leads to a large mesh distortion rate in the transition area, which makes numerical calculations prone to divergence and results in poor reliability. Summary of the Invention

[0010] This invention addresses the problems and shortcomings of existing technologies by providing a method, equipment, and medium for simulating the overall flow heat transfer of a printed circuit board heat exchanger.

[0011] The present invention solves the above-mentioned technical problems through the following technical solution: This invention provides a method for simulating the overall flow heat transfer of a printed circuit board heat exchanger, characterized by the following steps: S1. Based on the selected working fluid and operating condition range of the cold and hot channels, set the physical property parameters of the working fluid in the cold and hot channels respectively. Based on the operating conditions and flow characteristics of the cold and hot channels, select appropriate physical models and complete the parameter settings respectively. Establish the operating condition table for each channel respectively. Based on the relationship between the flow resistance characteristics of the single channel and the inlet flow rate, construct the single channel flow resistance model. S2. Divide the cold and hot aisles into cold and hot microchannels in the middle section and cold and hot runner systems on both sides. Construct cold and hot microchannel geometric models for each cold and hot microchannel and perform mesh generation to obtain cold and hot microchannel mesh models. Construct cold and hot runner system geometric models for each cold and hot runner system and perform mesh generation to obtain cold and hot runner system mesh models. S3. For the cold and hot microchannel geometric models, divide them along the length direction to obtain multiple one-to-one corresponding cold and hot treatment units. One cold treatment unit and the corresponding hot treatment unit constitute a heat exchange unit. For each heat exchange unit, construct a three-dimensional flow heat exchange geometric model with cross-sectional features. Mesh each three-dimensional flow heat exchange geometric model to obtain the corresponding three-dimensional flow heat exchange mesh model. Construct a one-dimensional model of the axial temperature distribution of the heat exchanger suitable for each heat exchange unit. S4. Simulate the cold and hot microchannel mesh models using the latest cold and hot channel working fluid properties, physical models, and single-channel flow resistance models. Simultaneously, simulate the cold and hot flow channel system mesh models using the cold and hot channel working fluid properties and physical models to obtain the flow distribution calculation results of the cold and hot microchannels. S5. Based on the inlet temperatures of the cold and hot microchannels, establish a temperature condition table containing the inlet temperatures of each cold and hot treatment unit. Based on the flow distribution calculation results of the cold and hot microchannels and the temperature condition table, perform simulation calculations on each three-dimensional flow heat transfer grid model to obtain the outlet temperature and heat transfer of each heat exchange unit, thereby obtaining the temperature of each cold and hot treatment unit, and then obtaining the convective heat transfer coefficient. Substitute the convective heat transfer coefficient of each heat exchange unit into the one-dimensional model of the axial temperature distribution of the heat exchanger to obtain the axial temperature distribution of the heat exchanger. S6. Update the working fluid properties of the cold and hot channels using the axial temperature distribution of the heat exchanger, and iterate until convergence.

[0012] The positive and progressive effects of this invention are as follows: 1. This invention solves the problems of difficult and large mesh size in full-size whole-machine fine modeling. It divides the cold and hot aisles into cold and hot microchannels in the middle section and cold and hot flow channel systems on both sides. It models the cold and hot microchannels separately and the cold and hot flow channel systems separately. While ensuring the calculation accuracy of core indicators, it significantly reduces the calculation cost and cycle and improves the practicality of engineering.

[0013] 2. This invention breaks through the limitations of the "uniform inlet assumption" of existing commonly used technologies, accurately simulates the fluid distribution process of cold and hot microchannels, quantifies flow velocity deviation and flow defects, and provides precise targets for channel structure optimization.

[0014] 3. This invention accurately captures the influence of flow resistance characteristics on flow heat transfer, and controls the calculation error within an acceptable range for engineering applications.

[0015] 4. This invention sets up different physical models according to the different flow states in the cold and hot channels. In addition, considering the characteristics of PCHE, the cold and hot channels are divided into cold and hot microchannels in the middle section and cold and hot flow channel systems on both sides. Different physical models are used for the cold and hot microchannels and the cold and hot flow channel systems, so as to accurately solve the axial temperature distribution of the heat exchanger, accurately obtain the flow heat transfer situation inside the cold and hot microchannels, and truly reflect the actual operating state of PCHE. Attached Figure Description

[0016] Figure 1 This is a flowchart of a heat exchanger whole-machine flow heat transfer simulation method according to a preferred embodiment of the present invention.

[0017] Figure 2 This is a model diagram of the cold and hot passages according to a preferred embodiment of the present invention.

[0018] Figure 3 This is a three-dimensional flow heat transfer geometric model diagram of a preferred embodiment of the present invention.

[0019] Figure 4 This is a comparison chart of the calculation results from this simulation method and the calculation results from direct modeling. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] like Figure 1 As shown, this embodiment of the invention provides a method for simulating the overall flow heat transfer of a printed circuit board heat exchanger (PCHE). The method divides the overall flow heat transfer simulation into two parts: flow distribution calculation and overall heat transfer performance analysis calculation. Through iteration, it achieves three-dimensional flow heat transfer analysis of the entire PCHE unit. Specifically, it includes the following steps: Step 101: Using the table import method, set the physical property parameters of the working fluid in the cold and hot channels according to the selected working fluid and operating condition range; determine the flow state in the cold and hot channels according to the operating conditions and flow characteristics of the cold and hot channels, select appropriate physical models and complete the parameter settings to achieve accurate simulation of flow heat transfer in the cold and hot channels; establish operating condition tables for each channel, and construct a single-channel flow resistance model based on the relationship between the flow resistance characteristics of the single channel and the inlet flow rate.

[0022] In this step, operating condition tables for each channel are established. Based on the relationship between the flow resistance characteristics of each channel and the inlet flow rate, a single-channel flow resistance model is constructed, including the following steps: S11. Select a single channel, establish a single-channel geometric model, and restore the channel type, cross-sectional shape, channel fillet, ridge width, plate stack thickness and length of the single channel.

[0023] S12. Mesh the single-channel geometric model to obtain a single-channel mesh model.

[0024] S13. Establish operating condition tables for each single channel.

[0025] S14. Based on the relationship between the flow resistance characteristics of a single channel and the inlet flow rate, construct a single-channel flow resistance model:

[0026] in, This represents the pressure drop in a single-channel flow. This represents the quadratic coefficient of the resistance term. This represents the first-order coefficient of the resistance term. This represents the density of the fluid in a single channel. This indicates the velocity of the fluid in a single channel.

[0027] The single-channel flow resistance model constructed in this step can be used as a physical model to simulate the cold and hot microchannel mesh models in S2. Through multiple experiments on the single channel, we can obtain... and The value of .

[0028] Step 102: Divide the cold and hot aisles into a middle section of cold and hot microchannels and two side sections of cold and hot runner systems (see...). Figure 2 , Figure 2 (Things that are not clearly visible in the text are not the focus of this invention and do not affect the technology of this invention.) For cold and hot microchannels, geometric models of cold and hot microchannels are constructed respectively, and meshing is performed to obtain mesh models of cold and hot microchannels respectively. For cold and hot flow channel systems, geometric models of cold and hot flow channel systems are constructed respectively, and meshing is performed to obtain mesh models of cold and hot flow channel systems respectively.

[0029] In this step, separate geometric models of cold and hot microchannels are constructed, and meshing is performed to obtain mesh models of cold and hot microchannels. Specifically, the following steps are included: Based on the manufacturing drawings and process data of the printed circuit board heat exchanger, separate geometric models of cold and hot microchannels are constructed to restore the channel type (straight channel / serrated channel), cross-sectional shape (semi-circular / rectangular), channel fillet (radius 0.1-0.5mm), ridge width (0.2-1mm), plate stack thickness (1-3mm), and length; meshing is performed on the geometric models of cold and hot microchannels to obtain mesh models of cold and hot microchannels.

[0030] For cold and hot runner systems, geometric models of the cold and hot runner systems are constructed separately, and mesh models of the cold and hot runner systems are obtained by meshing them separately. The specific steps include: Based on the manufacturing drawings and process data of the printed circuit board heat exchanger, geometric models of the cold and hot runner systems are constructed separately to restore the inlet and outlet manifolds, the flow distribution chambers (conical / spherical), and the transition sections between the manifolds and the cold and hot microchannels; the geometric models of the cold and hot runner systems are meshed separately to obtain the mesh models of the cold and hot runner systems.

[0031] Step 103: For the geometric models of cold and hot microchannels, divide them along the length direction to obtain multiple one-to-one cold and hot treatment units. One cold microchannel is divided into multiple cold treatment units, and one hot microchannel is divided into multiple hot treatment units. One cold treatment unit and its corresponding hot treatment unit constitute a heat exchange unit. For each heat exchange unit, construct a three-dimensional flow heat transfer geometric model with cross-sectional features (see...). Figure 3 The corresponding three-dimensional flow heat transfer mesh model is obtained by meshing each three-dimensional flow heat transfer geometric model, and a one-dimensional model of the axial temperature distribution of the heat exchanger suitable for each heat transfer unit is constructed.

[0032] In this step, a one-dimensional model of the axial temperature distribution of the heat exchanger applicable to each heat exchange unit is constructed:

[0033] in, and ... and These represent the temperature changes in the cold and heat treatment units, respectively. This represents the convective heat transfer coefficient of the heat exchange unit; and These represent the temperatures of the cold and heat treatment units, respectively. The length of the heat exchange unit is a known value.

[0034] The convective heat transfer coefficient of the heat exchange unit The results were obtained through simulation calculations using a three-dimensional flow heat transfer grid model. The specific formula is as follows:

[0035] in, This represents the amount of heat exchanged by a heat exchange unit. This represents the average temperature difference between the cold and heat treatment units in a heat exchange unit.

[0036]

[0037] in, and These represent the inlet and outlet temperatures of the heat treatment unit, respectively. and These represent the inlet and outlet temperatures of the refrigeration unit, respectively.

[0038] Step 104: Using the latest cold and hot channel working fluid properties, physical models, and single-channel flow resistance models, simulate and calculate the cold and hot microchannel mesh models respectively. Simultaneously, use the cold and hot channel working fluid properties and physical models to simulate and calculate the cold and hot flow channel system mesh models to obtain the flow distribution calculation results of the cold and hot microchannels.

[0039] Step 105: Based on the inlet temperatures of the cold and hot microchannels, establish a temperature condition table containing the inlet temperatures of each cold and hot treatment unit. Based on the flow distribution calculation results of the cold and hot microchannels and the temperature condition table, perform simulation calculations on each three-dimensional flow heat transfer grid model to obtain the outlet temperature and heat transfer of each heat exchange unit, thereby obtaining the temperature of each cold and hot treatment unit, and then obtaining the convective heat transfer coefficient. Substitute the convective heat transfer coefficient of each heat exchange unit into the one-dimensional model of the axial temperature distribution of the heat exchanger to obtain the axial temperature distribution of the heat exchanger.

[0040] In this step, a temperature condition table containing the inlet temperatures of each cold and hot treatment unit is established based on the inlet temperatures of the cold and hot microchannels. Simulation calculations are then performed on each three-dimensional flow heat transfer mesh model based on the flow distribution calculations of the cold and hot microchannels and the temperature condition table to obtain the outlet temperatures and heat transfer amounts of each heat transfer unit. .

[0041] Now that the inlet and outlet temperatures of the cold and heat treatment units in each heat exchange unit are known, the temperature of each cold and heat treatment unit can be calculated using formula (5). and The average temperature difference between the cold and heat treatment units was calculated using formula (4). At this point, the average temperature difference of each heat exchanger unit is already known. and heat exchange The convective heat transfer coefficient of each heat exchange unit is calculated using formula (3). .

[0042] The convective heat transfer coefficient of each heat exchange unit and the temperature of each cold and heat treatment unit and Substituting into the one-dimensional model of axial temperature distribution of the heat exchanger (2), the temperature changes of the cold and heat treatment units in each heat exchange unit are calculated. and This allows us to obtain the axial temperature distribution of the heat exchanger.

[0043] Step 106: Update the working fluid properties of the cold and hot channels using the axial temperature distribution of the heat exchanger, and iterate until convergence. The condition for convergence is that the axial temperature distribution of the heat exchanger remains unchanged in the two iterations.

[0044] The key points of this invention revolve around the PCHE whole-machine flow heat transfer simulation scheme, and the specific key points or inventive points are as follows: 1. A two-step iterative solution strategy is adopted, which combines PCHE flow distribution calculation with cold and hot microchannel flow heat transfer calculation. This paper proposes to split the PCHE simulation calculation into two parts: flow distribution calculation and cold and hot microchannel flow heat transfer calculation. The solutions are solved separately and then iteratively calculated. This approach overcomes the low efficiency of full-size modeling and improves the overall simulation efficiency.

[0045] 2. PCHE flow distribution calculation method based on three-dimensional models of cold and hot microchannels + flow resistance models of cold and hot microchannels Abandoning the "uniform inlet assumption" of existing technologies, this paper fully restores the geometry of the manifold, distribution cavity, and transition section through three-dimensional cold and hot microchannel models and three-dimensional cold and hot flow channel system models. It accurately simulates the diffusion of fluid in the manifold, the flow guidance in the distribution cavity, and the distribution process of the microchannel inlet, rather than just calculating the flow characteristics of a single channel.

[0046] 3. Solving for heat transfer in cold and hot microchannels using one-dimensional and three-dimensional models By establishing a one-dimensional model of the axial temperature distribution of the heat exchanger in cold and hot microchannels and a three-dimensional flow heat transfer model with cross-sectional features, the overall grid scale for flow heat transfer calculation in cold and hot microchannels is realized, thereby improving the calculation efficiency of flow heat transfer in cold and hot microchannels.

[0047] 4. Delineate hot and cold aisle physical model Abandoning the existing "uniform physical model" method, and considering the characteristics of PCHE, the cold and hot channels are divided into the middle section of cold and hot microchannels and the cold and hot flow channel systems on both sides. Different physical models are used for the cold and hot microchannels and the cold and hot flow channel systems respectively, so as to accurately solve the axial temperature distribution of the heat exchanger.

[0048] This invention also provides an electronic device, including: a processor; and a memory for storing processor-executable instructions; wherein the processor is configured to invoke the instructions stored in the memory to execute the aforementioned printed circuit board heat exchanger whole-machine flow heat transfer simulation method.

[0049] This invention also provides a computer-readable storage medium storing computer program instructions, which, when executed by a processor, implement the aforementioned simulation method for overall flow heat transfer of a printed circuit board heat exchanger.

[0050] This invention can be a method, apparatus, system, and / or computer program product. The computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for performing various aspects of the invention.

[0051] The simulation results obtained in this embodiment are compared with those obtained through direct modeling. It can be seen that the relative error between the flow distribution obtained by this simulation method and the flow obtained through direct simulation is less than 3%, and the mesh size can be reduced by several times. This simulation method can accurately reflect the overall performance of the PCHE system (see...). Figure 4 ).

[0052] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A method for simulating the overall flow heat transfer of a printed circuit board heat exchanger, characterized in that, Includes the following steps: S1. Based on the selected working fluid and operating condition range of the cold and hot channels, set the physical property parameters of the working fluid in the cold and hot channels respectively. Based on the operating conditions and flow characteristics of the cold and hot channels, select appropriate physical models and complete the parameter settings respectively. Establish the operating condition table for each channel respectively. Based on the relationship between the flow resistance characteristics of the single channel and the inlet flow rate, construct the single channel flow resistance model. S2. Divide the cold and hot aisles into cold and hot microchannels in the middle section and cold and hot runner systems on both sides. Construct cold and hot microchannel geometric models for each cold and hot microchannel and perform mesh generation to obtain cold and hot microchannel mesh models. Construct cold and hot runner system geometric models for each cold and hot runner system and perform mesh generation to obtain cold and hot runner system mesh models. S3. For the cold and hot microchannel geometric models, divide them along the length direction to obtain multiple one-to-one corresponding cold and hot treatment units. One cold treatment unit and the corresponding hot treatment unit constitute a heat exchange unit. For each heat exchange unit, construct a three-dimensional flow heat exchange geometric model with cross-sectional features. Mesh each three-dimensional flow heat exchange geometric model to obtain the corresponding three-dimensional flow heat exchange mesh model. Construct a one-dimensional model of the axial temperature distribution of the heat exchanger suitable for each heat exchange unit. S4. Simulate the cold and hot microchannel mesh models using the latest cold and hot channel working fluid properties, physical models, and single-channel flow resistance models. Simultaneously, simulate the cold and hot flow channel system mesh models using the cold and hot channel working fluid properties and physical models to obtain the flow distribution calculation results of the cold and hot microchannels. S5. Based on the inlet temperatures of the cold and hot microchannels, establish a temperature condition table containing the inlet temperatures of each cold and hot treatment unit. Based on the flow distribution calculation results of the cold and hot microchannels and the temperature condition table, perform simulation calculations on each three-dimensional flow heat transfer grid model to obtain the outlet temperature and heat transfer of each heat exchange unit, thereby obtaining the temperature of each cold and hot treatment unit, and then obtaining the convective heat transfer coefficient. Substitute the convective heat transfer coefficient of each heat exchange unit into the one-dimensional model of the axial temperature distribution of the heat exchanger to obtain the axial temperature distribution of the heat exchanger. S6. Update the working fluid properties of the cold and hot channels using the axial temperature distribution of the heat exchanger, and iterate until convergence.

2. The whole-machine flow heat transfer simulation method for printed circuit board heat exchangers as described in claim 1, characterized in that, In S1, operating condition tables for each channel are established. Based on the relationship between the flow resistance characteristics of a single channel and the inlet flow rate, a single-channel flow resistance model is constructed, including the following steps: S11. Select a single channel, establish a single-channel geometric model of the single channel, and restore the channel type, cross-sectional shape, channel fillet, ridge width, plate stack thickness and length of the single channel; S12. Mesh the single-channel geometric model to obtain a single-channel mesh model; S13. Establish operating condition tables for each single channel; S14. Based on the relationship between the flow resistance characteristics of a single channel and the inlet flow rate, construct a single-channel flow resistance model: ； in, This represents the pressure drop in a single-channel flow. This represents the quadratic coefficient of the resistance term. This represents the first-order coefficient of the resistance term. This represents the density of the fluid in a single channel. This indicates the velocity of the fluid in a single channel.

3. The whole-machine flow heat transfer simulation method for printed circuit board heat exchangers as described in claim 1, characterized in that, In S3, a one-dimensional model of the axial temperature distribution of the heat exchanger is constructed for each heat exchange unit: ； in, and These represent the specific heat capacities of the fluids in the cold and heat treatment units, respectively. and These represent the temperature changes in the cold and heat treatment units, respectively. This represents the convective heat transfer coefficient of the heat exchange unit. and These represent the temperatures of the cold and heat treatment units, respectively. Indicates the length of the heat exchange unit; The convective heat transfer coefficient of the heat exchange unit The results were obtained through simulation calculations using a three-dimensional flow heat transfer grid model. The specific formula is as follows: ； in, This represents the amount of heat exchanged by a heat exchange unit. This represents the average temperature difference between the cold and heat treatment units in a heat exchange unit; ； ； in, and These represent the inlet and outlet temperatures of the heat treatment unit, respectively. and These represent the inlet and outlet temperatures of the refrigeration unit, respectively.

4. The whole-machine flow heat transfer simulation method for printed circuit board heat exchangers as described in claim 3, characterized in that, In S5, a temperature condition table containing the inlet temperatures of each cold and hot treatment unit is established based on the inlet temperatures of the cold and hot microchannels. Simulation calculations are then performed on each three-dimensional flow heat transfer mesh model based on the flow distribution calculations of the cold and hot microchannels and the temperature condition table to obtain the outlet temperatures and heat transfer amounts of each heat transfer unit. ; The temperature of each cold and heat treatment unit is calculated using formula (5). and The average temperature difference between the cold and heat treatment units was calculated using formula (4). The convective heat transfer coefficient of each heat exchange unit is calculated using formula (3). ; The convective heat transfer coefficient of each heat exchange unit and the temperatures of each cold and heat treatment unit and Substituting into the one-dimensional model of axial temperature distribution of the heat exchanger (2), the temperature changes of the cold and heat treatment units in each heat exchange unit are calculated. and This allows us to obtain the axial temperature distribution of the heat exchanger.

5. The whole-machine flow heat transfer simulation method for printed circuit board heat exchangers as described in claim 1, characterized in that, In S6, the condition for the iteration to converge is that the axial temperature distribution of the heat exchanger remains unchanged in the two iterations.

6. The whole-machine flow heat transfer simulation method for printed circuit board heat exchangers as described in claim 1, characterized in that, In S2, geometric models of cold and hot microchannels are constructed separately, and meshing is performed separately to obtain mesh models of cold and hot microchannels. The specific steps include: Based on the manufacturing drawings and process data of printed circuit board heat exchangers, geometric models of cold and hot microchannels were constructed to restore the channel type, cross-sectional shape, channel fillet, ridge width, plate stack thickness and length. The geometric models of cold and hot microchannels are meshed separately to obtain cold and hot microchannel mesh models; For cold and hot runner systems, geometric models of the cold and hot runner systems are constructed separately, and mesh models of the cold and hot runner systems are obtained by meshing them separately. The specific steps include: Based on the manufacturing drawings and process data of printed circuit board heat exchangers, geometric models of cold and hot flow channel systems are constructed separately to recreate the inlet and outlet manifolds, the distribution chambers, and the transition sections between the manifolds and the cold and hot microchannels. The geometric models of the cold and hot runner systems are meshed separately to obtain the mesh models of the cold and hot runner systems.

7. The whole-machine flow heat transfer simulation method for printed circuit board heat exchangers as described in claim 1, characterized in that, In S1, the table import method is used to set the physical property parameters of the working fluid in the cold and hot channels according to the selected working fluid and operating condition range. Based on the operating conditions and flow characteristics of the cold and hot channels, the flow states within the cold and hot channels are determined, and appropriate physical models are selected and parameter settings are completed to achieve accurate simulation of heat transfer in the cold and hot channels.

8. An electronic device, characterized in that, include: processor; Memory used to store processor-executable instructions; The processor is configured to invoke instructions stored in memory to execute the whole-machine flow heat transfer simulation method for printed circuit board heat exchangers as described in any one of claims 1-7.

9. A computer-readable storage medium having computer program instructions stored thereon, characterized in that, When the computer program instructions are executed by the processor, they implement the whole-machine flow heat transfer simulation method for the printed circuit board heat exchanger as described in any one of claims 1-7.

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