Design method for structure and thermodynamic property based on micro-channel heat exchanger

Abstract

The invention provides a micro-channel heat exchanger-based structural and thermodynamic performance design method, which comprises the following steps of: setting initial structural parameters and thermodynamic boundary conditions of a micro-channel heat exchanger according to design requirements and working conditions; based on the initial structure parameters and the thermodynamic boundary conditions, thermodynamic properties, including a heat exchange coefficient and temperature distribution, of the micro-channel heat exchanger are calculated; pressure drop distribution of the hot side and the cold side of the micro-channel heat exchanger is calculated, and error verification is carried out; and based on the segmented thermodynamic properties and the pressure drop distribution, a design scheme is output by integrating the heat exchange efficiency, the pressure drop loss and the material cost.

Description

Technical Field

[0001] The present invention relates to the field of steel structure safety monitoring and evaluation, and particularly to a design method for the structure and thermodynamic performance based on a microchannel heat exchanger. Background Art

[0002] A heat exchanger is a core device in fields such as industrial production and energy conversion, and its designed performance directly affects the energy efficiency and operating cost of the system. In traditional heat exchanger designs, the structural parameters and thermodynamic performance parameters are usually optimized independently, making it difficult to fully consider the coupling effect between the two, resulting in it being difficult to achieve global optimization among heat transfer efficiency, pressure drop loss, and cost.

[0003] In the design of microchannel heat exchangers, the requirements for compactness and high-efficiency heat transfer are more prominent. Existing methods mostly determine the structural parameters first and then conduct thermodynamic performance analysis, but their efficiency is low and it is easy to cause problems of structural and performance mismatch. Especially under variable working conditions, single optimization is difficult to meet the requirements for efficient and stable operation under dynamic conditions.

[0004] Therefore, proposing a design method for the structure and thermodynamic performance based on a microchannel heat exchanger, which can achieve a comprehensive balance among heat transfer efficiency, pressure drop loss, and material cost, has become a key requirement for the design of microchannel heat exchangers. Summary of the Invention

[0005] In the first aspect of the present disclosure, a design method for the structure and thermodynamic performance based on a microchannel heat exchanger is provided, including:

[0006] According to the design requirements and working conditions, set the initial structural parameters and thermodynamic boundary conditions of the microchannel heat exchanger;

[0007] Based on the initial structural parameters and the thermodynamic boundary conditions, calculate the thermodynamic performance of the microchannel heat exchanger, including the heat transfer coefficient and temperature distribution;

[0008] Calculate the pressure drop distributions on the hot side and cold side of the microchannel heat exchanger and conduct error verification;

[0009] Based on the segmented thermodynamic performance and the pressure drop distribution, output a design scheme by comprehensively considering heat transfer efficiency, pressure drop loss, and material cost.

[0010] Combined with the first aspect, the setting of the initial structural parameters and thermodynamic boundary conditions of the microchannel heat exchanger according to the design requirements and working conditions includes:

[0011] Set the initial structural parameters of the microchannel heat exchanger, including the total length L, channel cross-sectional area A c , equivalent plate thickness t e , number of segments N, number of pipes M, heat transfer area A;

[0012] Set the thermodynamic boundary conditions of the microchannel heat exchanger, including the flow rates m h and m c on the hot and cold sides of the microchannel heat exchanger, the temperatures T hi , T ci and the pressures P hi , P ci .

[0013] Combined with the first aspect, calculating the segmented thermodynamic performance of the microchannel heat exchanger based on the initial structural parameters and the thermodynamic boundary conditions includes:

[0014] Calculating the heat transfer coefficient where h h is the heat transfer coefficient on the hot side, h c is the heat transfer coefficient on the cold side, and k w is the thermal conductivity of the metal wall;

[0015] Calculating the heat transfer quantity Q = U·A·(T h - T c ) segment by segment using the heat transfer coefficient, where T h is the temperature of the working fluid on the hot side, and T c is the temperature of the working fluid on the cold side;

[0016] Updating the temperature segment by segment using the heat transfer quantity where T in is the initial temperature, m is the flow rate, and c p is the specific heat at constant pressure.

[0017] Combined with the first aspect, calculating the pressure drop distributions on the hot and cold sides of the microchannel heat exchanger and performing error verification includes:

[0018] Calculating the pressure drop where f is the friction factor, ρ is the density, u is the flow velocity, d is the equivalent diameter, and dx is the length of the heat exchange section;

[0019] Calculating the temperature error through the following calculation formula:

[0020] error T = max(max|T h - T hold |, max|T c - T cold |),

[0021] where T h is the hot side temperature calculated in this iteration, T c is the cold side temperature calculated in this iteration, T hold is the hot side temperature obtained in the previous iteration, and T coldThe cold-side temperature obtained in the previous iteration

[0022] Calculate the pressure error through the following calculation formula:

[0023] error P = max(max|P h - P hold |, max|P c - P cold |),

[0024] P h is the hot-side pressure calculated in this iteration, P c is the cold-side pressure calculated in this iteration, P hold is the hot-side pressure obtained in the previous iteration, P cold the cold-side pressure obtained in the previous iteration;

[0025] Compare the calculated error with the preset error tolerance range. If the error is less than the tolerance value, the iteration ends; otherwise, continue the next iteration.

[0026] Combined with the first aspect, the design scheme outputting the comprehensive heat transfer efficiency, pressure drop loss, and material cost based on the segmented thermodynamic performance and the pressure drop distribution includes:

[0027] Establish the objective function F = w 1 ·η Q - w 2 ·ΔP total + w 3 ·cost,

[0028] where η Q is the heat transfer efficiency, ΔP total is the total pressure loss, cost is the material cost, and w 1 、w 2 、w 3 are the corresponding weights respectively;

[0029] According to the initial structural parameters, use the multi-objective optimization algorithm to iteratively optimize the design parameters within the thermodynamic boundary conditions and output the optimized design scheme.

[0030] Combined with the first aspect, the multi-objective optimization algorithm includes a genetic algorithm, a particle swarm algorithm, or a simulated annealing algorithm.

[0031] In the second aspect of the present disclosure, an electronic device is provided, including:

[0032] One or more processors;

[0033] A storage unit for storing one or more programs, which, when executed by the one or more processors, enable the one or more processors to implement any one of the above design methods for the structure and thermodynamic performance of a microchannel heat exchanger.

[0034] In a third aspect of the present disclosure, there is provided a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, can implement any one of the above design methods for the structure and thermodynamic performance of a microchannel heat exchanger.

[0035] Advantageous effects: By combining thermodynamic theory calculations, pressure drop analysis, and multi-objective optimization algorithms, and based on computational fluid dynamics (CFD) simulations and empirical formulas, the present invention establishes an efficient collaborative optimization design method for the structure and performance of a microchannel heat exchanger. By specifying the initial structural parameters and thermodynamic boundary conditions, calculating the heat transfer coefficient, temperature distribution, and pressure drop distribution in segments, and verifying the errors, the accuracy and stability of the calculation results are ensured. By constructing a multi-objective optimization function with heat transfer efficiency, pressure drop loss, and material cost as objectives, the design parameters are optimized, and the optimal heat exchanger structure scheme is output. The present invention effectively improves the heat transfer efficiency, reduces the pressure drop loss and material cost, improves the design flexibility and applicability, provides an efficient and economical heat exchanger design scheme for engineering practice, and has broad application value. Description of the Drawings

[0036] Figure 1 A design method for the structure and thermodynamic performance of a microchannel heat exchanger according to an embodiment of the present disclosure;

[0037] Figure 2 A schematic structural diagram of an electronic device according to an embodiment of the present disclosure. Detailed Embodiments

[0038] Here, the exemplary embodiments will be described in detail, and the examples are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the embodiments of the present disclosure.

[0039] The terms used in the embodiments of the present disclosure are only for the purpose of describing specific embodiments, and are not intended to limit the embodiments of the present disclosure. The singular forms "a", "the", and "said" used in the embodiments of the present disclosure and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0040] It should be understood that although terms such as first, second, and third may be used in the embodiments of the present disclosure to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of the embodiments of the present disclosure, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "when" or "while" or "in response to determining".

[0041] As Figure 1 shown, a design method for the structure and thermodynamic performance of a microchannel heat exchanger according to an embodiment of the present disclosure includes:

[0042] S101: Set the initial structural parameters and thermodynamic boundary conditions of the microchannel heat exchanger according to the design requirements and operating conditions,

[0043] Specifically, according to the design requirements and operating conditions, set the initial structural parameters of the microchannel heat exchanger, including the total length L, channel cross-sectional area A c , equivalent plate thickness t e , number of segments N, number of pipes M, heat transfer area A,

[0044] Set the thermodynamic boundary conditions of the microchannel heat exchanger, including the flow rates m h and m c , temperatures T hi , T ci and pressures P hi , P ci .

[0045] S102: Calculate the thermodynamic performance of the microchannel heat exchanger based on the initial structural parameters and the thermodynamic boundary conditions, including the heat transfer coefficient and temperature distribution,

[0046] Specifically, calculating the sectional thermodynamic performance of the microchannel heat exchanger includes:

[0047] Calculate the heat transfer coefficient where h h is the heat transfer coefficient on the hot side, h c is the heat transfer coefficient on the cold side, and k w is the thermal conductivity of the metal wall;

[0048] Calculate the heat transfer amount Q = U·A·(T h -T c ) using the heat transfer coefficient segment by segment, where T h is the temperature of the working fluid on the hot side, and T c is the temperature of the working fluid on the cold side;

[0049] Update the temperature segment by segment using the heat transfer amount where T in is the initial temperature, m is the flow rate, and c p is the specific heat at constant pressure

[0050] S103: Calculate the pressure drop distributions on the hot side and the cold side of the microchannel heat exchanger, and perform error verification

[0051] Specifically, calculate the pressure drop where f is the friction factor, ρ is the density, u is the flow velocity, d is the equivalent diameter, and dx is the length of the heat exchange section

[0052] Calculate the temperature error through the following calculation formula

[0053] error T = max(max|T h - T hold |, max|T c - T cold |),

[0054] where T h is the hot side temperature of the current iteration calculation, T c is the cold side temperature of the current iteration calculation, T hold is the hot side temperature obtained from the previous iteration, T cold the cold side temperature obtained from the previous iteration

[0055] Calculate the pressure error through the following calculation formula

[0056] error P = max(max|P h - P hold |, max|P c - P cold |),

[0057] P h is the hot side pressure of the current iteration calculation, P c is the cold side pressure of the current iteration calculation, P hold is the hot side pressure obtained from the previous iteration, P cold the cold side pressure obtained from the previous iteration

[0058] Compare the calculated error with the preset error tolerance range. If the error is less than the tolerance value, the iteration ends; otherwise, continue the next iteration

[0059] S104: Based on the segmented thermodynamic performance and the pressure drop distribution, output a design solution by comprehensively considering the heat transfer efficiency, pressure drop loss, and material cost

[0060] Specifically, it includes

[0061] Establish the objective function \(F = w\) 1 ·\(\eta\) Q - w 2 ·\(\Delta P\) total + w 3 ·cost,

[0062] where \(\eta\) Q is the heat transfer efficiency, \(\Delta P\) total is the total pressure loss, cost is the material cost, and \(w\) 1 , \(w\) 2 , \(w\) 3 are the corresponding weights respectively;

[0063] According to the initial structural parameters, use the multi-objective optimization algorithm to iteratively optimize the design parameters within the thermodynamic boundary conditions, and output the optimized design scheme.

[0064] Exemplarily, the initial structural parameters and thermodynamic boundary conditions of the microchannel heat exchanger in step S101 include:

[0065] Take a supercritical carbon dioxide-water printed circuit board heat exchanger, with the design condition parameters of 450 kg / s on the cold side, 150 kg / s on the hot side, the inlet and outlet temperatures of the hot side being 70 °C and 40 °C, the outlet temperature of the cold side being 25 °C and 35 °C, and the expected length of the heat exchanger being less than 1.2 m.

[0066] Furthermore, calculating the heat transfer coefficient in step S102 includes:

[0067] Calculate the flow velocity \(u = m / (\rho*A\) c ), where \(\rho\) is the density and \(m\).

[0068] Calculate the Reynolds number using the flow velocity where \(\mu\) is the viscosity coefficient and \(d\) is the equivalent diameter.

[0069] Calculate the friction factor \(f = 0.3164·Re\) -0.25 .

[0070] Calculate the Prandtl number according to the fluid thermophysical properties where \(c\) p is the specific heat at constant pressure and \(k\) is the thermal conductivity.

[0071] Calculate the Nusselt number using the above data

[0072] Calculate the heat transfer coefficient using the Nusselt number

[0073] Calculate the total heat transfer coefficient where \(k\) w is the thermal conductivity of the metal wall.

[0074] Calculate the heat transfer quantity Q section by section using the heat transfer coefficient j = U·A·(Th j - Tc j ), where Th j is the hot-side working fluid temperature of the j-th heat transfer section, and Tc j is the cold-side working fluid temperature of the j-th heat transfer section.

[0075] Update the temperature section by section using the heat transfer quantity

[0076] Furthermore, calculating the pressure drop distributions on the hot side and the cold side of the microchannel heat exchanger in step S103 and performing error verification includes:

[0077] In each heat transfer section, calculate the pressure drops on the hot side and the cold side based on the flow characteristics of the fluid, and accumulate them section by section to form a complete pressure distribution. At the same time, set up an error verification step to detect whether the changes in the temperature and pressure distributions in each iteration are within the allowable error range to ensure the convergence and stability of the calculation results.

[0078] Calculate the pressure drop section by section using the friction factor where dx is the length of the heat transfer section.

[0079] Update the pressure section by section to form a complete pressure distribution along the path.

[0080] After each round of iteration is completed, perform error verification, compare the temperature and pressure distributions of this round of iteration with the results of the previous round to judge the convergence:

[0081] Deviation calculation formula Error calculation formula:

[0082] error T = max(max|T h - T hold |, max|T c - T cold |),

[0083] error P = max(max|P h - P hold |, max|P c - P cold |), where T h is the hot-side temperature calculated in this iteration, T hold is the hot-side temperature obtained in the previous round of iteration, error T is the maximum value of the temperature deviation between the two rounds; the deviation calculation formula for pressure calculation is the same as that for temperature.

[0084] The calculated maximum error is compared with the preset error tolerance range (such as 0.1 K or 0.1 KPa). If the error is less than the tolerance value, the iteration ends; otherwise, the next iteration continues.

[0085] Further, in step S104, based on the segmented thermodynamic performance and the pressure drop distribution, the design scheme output by comprehensively considering the heat transfer efficiency, pressure drop loss, and material cost includes:

[0086] Based on the preliminary iteration results, through the collaborative optimization of the structural parameters and thermodynamic performance parameters, the structural configuration and operating conditions of the heat exchanger are gradually adjusted to achieve efficient heat transfer effects and the lowest material cost.

[0087] A multi-objective optimization function is established, including objectives such as heat transfer efficiency, pressure drop loss, and material cost. The weighting coefficients are used to balance the weights of each objective. On the premise of meeting the design requirements, the overall material cost and pressure drop loss of the heat exchanger are minimized, and the heat transfer efficiency is maximized.

[0088] The objective function F = w 1 ·η Q -w 2 ·ΔP total +w 3 ·cost. η Q is the heat transfer efficiency, representing the ratio of the heat transfer amount to the design maximum value; ΔP total is the total pressure loss; cost is the material cost; w 1 、w 2 、w 3 are the weights of each objective.

[0089] In the synchronous optimization of the structural parameters and thermodynamic performance parameters, in each iteration, using the calculation result of the objective function F, the structural parameters (such as the channel cross-sectional area A c etc.) and thermodynamic performance parameters (such as the temperature T etc.) are dynamically adjusted to ensure the collaborative optimization of the structure and thermal performance.

[0090] Set the boundary conditions of the structural and operating condition parameters to ensure that the optimization algorithm explores within a reasonable design range and avoids unrealistic structural and operating condition parameters.

[0091] After the collaborative optimization process ends, the optimal design scheme is output, including the complete data of the temperature and pressure distributions along the hot side and cold side, and including: the overall heat transfer coefficient U, heat transfer efficiency, material cost, total pressure drop loss, and the optimized structural configuration (such as the best channel cross-sectional area A c 、equivalent plate thickness t e etc.), providing a reference basis for actual production.

[0092] By calculating in 50 segments and repeating the above iterative steps, the length of the heat exchanger satisfying the structural parameter range is 1.2 m, the width is 0.6 m, and the height is 4.5 m. With the existing processing technology, about 10 heat exchanger cores need to be connected in parallel.

[0093] The electronic device 200 can be a desktop computer, a notebook, a palm computer, a cloud server, or other electronic devices. The electronic device 200 may include, but is not limited to, a processor 201 and a memory 202. Those skilled in the art can understand that Figure 2 merely examples of the electronic device 200, which do not constitute a limitation on the electronic device 200, may include more or fewer components than shown in the figure, or combine some components, or different components. For example, the electronic device may also include input / output devices, network access devices, buses, etc.

[0094] The processor 201 can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc.

[0095] The memory 202 can be an internal storage unit of the electronic device 200. For example, the hard disk or memory of the electronic device 200. The memory 202 can also be an external storage device of the electronic device 200. For example, a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the electronic device 200. Further, the memory 202 can also include both the internal storage unit of the electronic device 200 and the external storage device. The memory 202 is used to store the computer program 203 and other programs and data required by the electronic device. The memory 202 can also be used to temporarily store the data that has been output or will be output.

[0096] In the embodiments provided in the present disclosure, it should be understood that the disclosed device / electronic device and method can be implemented in other ways. For example, the device / electronic device embodiments described above are merely illustrative. For example, the division of modules or units is only a logical function division. In actual implementation, there may be other division methods. Multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection to each other can be through some interfaces. The indirect coupling or communication connection of the device or unit can be in electrical, mechanical or other forms.

[0097] In addition, in each embodiment of the present disclosure, each functional unit can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0098] The above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them; although the present disclosure has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of each embodiment of the present disclosure, and should all be included in the protection scope of the present disclosure.

Claims

1. A design method based on the structure and thermodynamic performance of a microchannel heat exchanger, characterized in that: include: According to the design requirements and working conditions, the initial structural parameters and thermodynamic boundary conditions of the microchannel heat exchanger are set; Based on the initial structural parameters and the thermodynamic boundary conditions, calculating the thermodynamic performance of the microchannel heat exchanger, including heat transfer coefficient and temperature distribution; Calculating the pressure drop distribution on the hot side and the cold side of the microchannel heat exchanger and performing error checking; Based on the segmented thermodynamic performance and the pressure drop distribution, a design solution is output by comprehensively considering heat exchange efficiency, pressure drop loss and material cost.

2. The method according to claim 1, characterized in that According to the design requirements and working conditions, the initial structural parameters and thermodynamic boundary conditions of the microchannel heat exchanger are set, including: Set the initial structural parameters of the microchannel heat exchanger, including the total length L of the microchannel heat exchanger, the channel cross-sectional area A c , equivalent plate thickness t e , number of sections N, number of pipes M, heat exchange area A; The thermodynamic boundary conditions of the microchannel heat exchanger are set, including the flow rates m on the hot side and the cold side of the microchannel heat exchanger. h and m c , Temperature T hi , T ci and pressure P hi , P ci .

3. The method according to claim 1, characterized in that The calculating the segmented thermodynamic performance of the microchannel heat exchanger based on the initial structural parameters and the thermodynamic boundary conditions comprises: Calculate the heat transfer coefficient where h h is the heat transfer coefficient on the hot side, h c is the cold side heat transfer coefficient, k w is the thermal conductivity of the metal wall; Calculate the heat transfer coefficient section by section Q = U·A·(T h -T c ), where T h is the hot side working fluid temperature, T c is the working fluid temperature on the cold side; Use heat exchange to update the temperature step by step Where T in is the initial temperature, m is the flow rate, c p is the specific heat at constant pressure.

4. The method according to claim 1, characterized in that: The calculating the pressure drop distribution on the hot side and the cold side of the microchannel heat exchanger and performing error checking comprises: Calculate pressure drop Where f is the friction factor, ρ is the density, u is the flow velocity, d is the equivalent diameter, and dx is the length of the heat exchange section; The temperature error is calculated using the following formula: error T =max(max|T h -T hold |,max|T c -T cold |), Among them, T h is the hot side temperature calculated in this iteration, T c is the cold side temperature of this iteration calculation, T hold is the hot side temperature obtained in the previous iteration, T cold The cold side temperature obtained in the previous iteration, The pressure error is calculated using the following formula: error P =max(max|P h -P hold |,max|P c -P cold |), P h is the hot side pressure calculated in this iteration, P c is the cold side pressure of this iteration calculation, P hold is the hot side pressure obtained in the previous iteration, P cold The cold side pressure obtained in the previous iteration; The calculated error is compared with the preset error tolerance range. If the error is less than the tolerance, the iteration ends, otherwise the next round of iteration continues.

5. The method according to claim 1, characterized in that The design scheme based on the segmented thermodynamic performance and the pressure drop distribution, comprehensive heat exchange efficiency, pressure drop loss and material cost output includes: Establish the objective function F = w1·η Q -w2·ΔP total +w3·cost, Among them, η Q is the heat transfer efficiency, ΔP total is the total pressure loss, cost is the material cost, w1, w2, and w3 are the corresponding weights respectively; According to the initial structural parameters, a multi-objective optimization algorithm is used to iteratively optimize the design parameters within the thermodynamic boundary conditions, and an optimized design solution is output.

6. The method according to claim 1, characterized in that The multi-objective optimization algorithm includes a genetic algorithm, a particle swarm algorithm or a simulated annealing algorithm.

7. An electronic device, characterized in that: include: one or more processors; A storage unit for storing one or more programs, which, when executed by the one or more processors, enable the one or more processors to implement the design method based on the structure and thermodynamic performance of the microchannel heat exchanger according to any one of claims 1 to 6.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, it can implement the design method based on the structure and thermodynamic performance of the microchannel heat exchanger according to any one of claims 1 to 6.

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