Performance prediction method and system for cooling channel
By employing a step-by-step modeling and iterative calculation method, the problem of high-precision prediction of the cooling fuel and air sidewall temperatures in the cooling channels of high Mach number aircraft was solved, enabling global performance prediction and optimization of the cooling channel system and providing accurate data support for key performance indicators.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NAT UNIV OF DEFENSE TECH
- Filing Date
- 2026-03-27
- Publication Date
- 2026-05-01
AI Technical Summary
Existing technologies struggle to accurately predict changes in the temperature of cooling fuel and the temperature of the air sidewalls in the cooling channels of high Mach number aircraft, resulting in complex and costly heat transfer calculations that fail to meet the requirements for stable flight of aircraft.
By employing a step-by-step modeling, discrete element, and iterative calculation strategy, the performance of the cooling channel system, including the heat exchange and temperature distribution of cooling fuel and hot air, is calculated step by step by constructing a convective heat transfer coefficient model, an overall heat transfer coefficient model, and a temperature distribution model on the cold and hot fluid sides.
It enables high-precision, global performance prediction of complex cooling channel systems, outputting cooling oil temperature distribution, hot air temperature distribution, and air sidewall temperature distribution, supporting heat exchange efficiency assessment and system optimization, and revealing potential hot spot areas.
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Figure CN121960296A_ABST
Abstract
Description
A method and system for predicting the performance of cooling channels Technical Field
[0001] This invention belongs to the field of cooling channel performance prediction, specifically relating to a method and system for predicting the performance of cooling channels. Background Technology
[0002] Cooling the various components of an aircraft is a key technology to ensure its performance during operation. Early low-Mach number aircraft often used passive cooling methods, where incoming air passively cooled the components. However, as flight altitudes and Mach numbers increase, traditional passive cooling is no longer sufficient for stable flight. The method of designing cooling channels within aircraft components and using cooling fuel to cool them is now widely used in modern aircraft products.
[0003] Accurate prediction of the oil temperature in the air-side wall and cooling channels is crucial for the overall layout and channel design of aircraft. However, since the properties of injected fuel change drastically with temperature, these changes lead to changes in heat transfer, which in turn cause temperature changes. Therefore, predicting the temperature of the cooling fuel for aircraft has become a challenge.
[0004] In recent years, CFD (Computational Fluid Dynamics) simulation methods have emerged. Among CFD methods, the VOF (Volume Fluid Model) has relatively accurate prediction results for fluids with phase change properties. However, the geometric scale of the finned parts is too small compared to the global scale. In addition, the VOF model requires geometric reconstruction. Therefore, using CFD methods to perform coupled heat transfer calculations of wall temperature and oil temperature will increase the computation cycle and computational cost, making it unsuitable for the structural finalization design of early aircraft. Summary of the Invention
[0005] The technical problem to be solved by this invention is to provide a method and system for predicting the performance of cooling channels. The method achieves high-precision, global prediction of the performance of complex cooling channel systems through a strategy of step-by-step modeling, discrete elements, and iterative calculation.
[0006] This invention provides a method for predicting the performance of cooling channels, comprising the following steps:
[0007] S1. Determine the basic parameters, including the structural parameters of the cooling channel side and the air side, the physical properties of the hot and cold fluids, and the fluid inlet conditions; S2. Construct a calculation model for the convective heat transfer coefficient on the hot and cold fluid side. This model calculates the convective heat transfer coefficient on the cooling fuel side and the convective heat transfer coefficients on the outgoing and returning hot air sides based on the basic parameters, Reynolds number, Prandtl number, heat transfer factor, and fluid mass flow rate; S3. Construct a calculation model for the overall heat transfer coefficient. This model is based on the outgoing and returning cooling fin efficiency coefficients. The overall efficiency of the fin surface on the fluid side, the thermal resistance of the outgoing and returning baffles, the convective heat transfer coefficient of the cooling fuel side, and the convective heat transfer coefficients of the outgoing and returning hot air sides are calculated. The overall heat transfer coefficients between the outgoing cooling oil and hot air, and between the returning cooling oil and hot air are also calculated. S4, the hot and cold fluid regions are divided into an outgoing total unit channel and a returning total unit channel. The outgoing total unit channel is further divided into an outgoing cooling fuel unit channel and an outgoing hot air unit channel, and the returning total unit channel is divided into a returning cooling fuel unit channel and a returning hot air unit channel. Based on the overall heat transfer coefficient, the following is adopted... The following steps are performed: S5, constructing a model for calculating the outlet temperatures of the cold and hot fluid units. This model calculates the outlet temperatures of the cold and hot fluid units based on the heat exchange between the cold and hot fluid units and the return cooling oil and hot air. S6, calculating the outlet temperatures of the cold and hot fluid units based on the heat exchange between the cold and hot fluid units and the return cooling oil and hot air. S7, dividing the cold and hot fluid units into several identical macrocells along the flow direction, constructing a temperature distribution model. This model substitutes the initial inlet conditions into the first macrocell and uses the outlet temperature of the previous macrocell as the inlet temperature of the next macrocell. S8 iteratively solves steps S4 to S6 to obtain the temperature distributions of the cold and hot fluid units for both the cold and hot fluid units.
[0008] Furthermore, the temperature distribution model includes: S71, discretizing the outgoing and returning total unit channels into multiple macrocells of equal number along their respective flow directions; S72, starting from the first macrocell in the outgoing direction, using the fluid inlet conditions determined in S1 for the inlet temperatures of the cooling oil and hot air; sequentially performing S4 to S6 on this macrocell to calculate its outlet temperature and wall temperature; and using this outlet temperature as the inlet temperature of the next adjacent macrocell, repeating the above calculations until all outgoing macrocells are solved, thereby obtaining... The cooling oil temperature distribution, hot air temperature distribution, and air sidewall temperature distribution in the outgoing direction are obtained; S73, the cooling oil inlet temperature of the first macrocell in the return direction is taken from the cooling oil outlet temperature of the last macrocell in the outgoing direction calculated in S72; the hot air inlet temperature of this macrocell is the same as the hot air inlet temperature of the first macrocell in the outgoing direction in S72; thereafter, following the same iteration rule as S72, all macrocells in the return direction are solved sequentially to finally obtain the cooling oil temperature distribution, hot air temperature distribution, and air sidewall temperature distribution in the return direction.
[0009] Furthermore, the aforementioned adoption The method calculates the heat exchange between the outgoing cooling oil and hot air in the outgoing unit channel and the heat exchange between the returning cooling oil and hot air in the returning unit channel, including a calculation model for the heat exchange of the total unit channel. The calculation model for the heat exchange of the total unit channel is as follows: ; In the formula, ε0 represents the heat exchange between the cooling oil and hot air during the outgoing journey; ε1 represents the outgoing journey heat transfer efficiency; C min T is the product of the minimum specific heat capacity of the hot and cold media and the flow rate; in,air去 T represents the inlet temperature of the outgoing hot air unit. in,冷却油去 This refers to the inlet temperature of the outgoing cooling oil unit. ε2 is the heat exchange between the return cooling oil and the hot air; ε3 is the return heat transfer efficiency; C min T is the product of the minimum specific heat capacity of the hot and cold media and the flow rate; in,air回 T represents the inlet temperature of the return hot air unit. in,冷却油回 This refers to the inlet temperature of the return cooling oil unit.
[0010] Furthermore, the calculation model for the outlet temperature of the hot and cold fluid unit is as follows: ; ; ; In the formula, T out,冷却油去 This refers to the outlet temperature of the outgoing cooling oil unit. The heat exchanged between the cooling oil and hot air during the outward journey; C represents the mass flow rate of the cooling oil. p冷却油去 T represents the specific heat capacity of the cooling oil on the outgoing route.in,冷却油去 is the inlet temperature of the outgoing cooling oil unit; T out,air去 is the outlet temperature of the outgoing hot air unit; is the heat exchange amount between the return cooling oil and hot air; is the mass flow rate of the hot air; C p热空气去 is the specific heat capacity of the outgoing hot air; T in,air去 is the inlet temperature of the outgoing hot air unit; T out,冷却油回 is the outlet temperature of the return cooling oil unit; T in,冷却油回 is the inlet temperature of the return cooling oil unit; T out,air回 is the outlet temperature of the return hot air unit; C p热空气回 is the specific heat capacity of the return hot air; T in,air回 is the inlet temperature of the return hot air unit.
[0011] Furthermore, in the S1, the structural parameters of the cooling channel side and the air side include: the number of cooling oil fluid channels for the outgoing and return trips, the total heat dissipation area, the flow area, the hydraulic diameter, and the secondary heat exchange area of the fins; among them, the heat dissipation area, the flow area, and the hydraulic diameter of a single channel are calculated based on geometric parameters such as the channel width, the fin thickness, the fin height, the channel length, and the bottom thickness of the channel.
[0012] Furthermore, in the S1, the physical properties of the hot and cold fluids include fluid density, specific heat capacity at constant pressure, thermal conductivity, and dynamic viscosity; the values of the physical properties are determined based on the temperature of the fluid at the inlet of the corresponding flow unit.
[0013] Furthermore, in the S2, the calculation models for the convective heat transfer coefficients on the hot and cold fluid sides include: first, calculate the Reynolds number based on the fluid mass flow rate, the hydraulic diameter, and the dynamic viscosity, calculate the Prandtl number based on the specific heat capacity at constant pressure, the dynamic viscosity, and the thermal conductivity, then calculate the cooling fuel heat transfer factor according to the relationship with the Reynolds number, and calculate the convective heat transfer coefficient on the cooling fuel side based on the Prandtl number and the cooling fuel heat transfer factor according to the calculation model for the convective heat transfer coefficient on the cooling fuel side, and calculate the convective heat transfer coefficients on the outgoing and return hot air sides according to the calculation models for the convective heat transfer coefficients on the outgoing and return hot air sides; the calculation model for the convective heat transfer coefficient on the cooling fuel side is: ; where j is the cooling fuel heat transfer factor; C P is the specific heat capacity at constant pressure; M is the mass flow rate of the hot and cold side fluids; Pr is the Prandtl number of the hot and cold fluids; i = 1, 2; 1 is the outgoing cooling channel side, 2 is the return cooling channel side; the calculation models for the convective heat transfer coefficients on the outgoing and return hot air sides are: ; ; where is the thermal conductivity; De is the hydraulic diameter; air_go is the outgoing air side; air_return is the return air side.
[0014] Furthermore, the overall heat transfer coefficient calculation model is as follows: ; In the formula, K1 is the total heat transfer coefficient between the outgoing cooling oil and the hot air; A1 is the heat dissipation area of a single outgoing cooling oil channel; and h1 is the convective heat transfer coefficient of the outgoing cooling fuel side. R represents the total efficiency of the fin surface on the outgoing fluid side; w For the thermal resistance of the partition; h air去 A is the convective heat transfer coefficient on the outgoing hot air side; air去 The heat dissipation area on the hot air side matched with the outgoing cooling oil channel: K2 is the total heat transfer coefficient between the return cooling oil and hot air; A2 is the heat dissipation area of a single return cooling oil channel; h2 is the convective heat transfer coefficient on the return cooling fuel side. h represents the total efficiency of the fin surface on the return fluid side. air回 A is the convective heat transfer coefficient on the return hot air side; air回 The heat dissipation area on the hot air side is matched with the return flow and the cooling oil channel.
[0015] Furthermore, the thermal resistance of the partition is calculated using a partition thermal resistance calculation model: The partition thermal resistance calculation model is as follows: ; In the formula, R w去 For the outgoing flow partition thermal resistance; R w回 For the return baffle thermal resistance; The thickness of the groove bottom; The thermal conductivity of the partition; This refers to the heat dissipation area on the outgoing hot air side; This refers to the heat dissipation area on the return hot air side.
[0016] This invention also provides a performance prediction system for cooling channels, characterized by comprising: a basic parameter determination module, used for S1:S1, determining basic parameters, including structural parameters of the cooling channel side and air side, physical property parameters of hot and cold fluids, and fluid inlet conditions; a hot and cold fluid side convective heat transfer coefficient calculation module, used for S2:S2, constructing a calculation model for the hot and cold fluid side convective heat transfer coefficient, wherein the calculation model calculates the convective heat transfer coefficient of the cooling fuel side and the convective heat transfer coefficients of the outgoing and returning hot air sides based on the basic parameters, Reynolds number, Prandtl number, heat transfer factor, and combined with the fluid mass flow rate; and a total heat transfer coefficient calculation module, used for S3:S3, constructing the total heat transfer coefficient... The heat transfer coefficient calculation model calculates the overall heat transfer coefficient based on the fluid-side fin surface efficiency, outgoing and returning baffle thermal resistance, cooling fuel side convective heat transfer coefficient, and outgoing and returning hot air side convective heat transfer coefficient. It then calculates the overall heat transfer coefficient between the outgoing cooling oil and hot air, and between the returning cooling oil and hot air. A heat transfer calculation module is used to perform S4:S4, dividing the hot and cold fluid regions into an outgoing total unit channel and a returning total unit channel. The outgoing total unit channel is further divided into an outgoing cooling fuel unit channel and an outgoing hot air unit channel, and the returning total unit channel is divided into a returning cooling fuel unit channel and a returning hot air unit channel. Based on the overall heat transfer coefficient, the model employs... The method calculates the heat exchange between the outgoing cooling oil and hot air in the outgoing main unit channel and the heat exchange between the returning cooling oil and hot air in the returning main unit channel; the heat exchange calculation module is used to perform S5:S5, constructing a calculation model for the outlet temperature of the cold and hot fluid units. The outlet temperature calculation model of the cold and hot fluid units calculates the outlet temperature of the outgoing cooling fuel unit channel, the outlet temperature of the outgoing hot air unit channel, the outlet temperature of the returning cooling fuel unit channel, and the outlet temperature of the returning hot air unit channel based on the heat exchange between the outgoing cooling oil and hot air and the returning cooling oil and hot air; the air side wall temperature calculation module uses... In S6:S6, the outbound air sidewall temperature and the return air sidewall temperature are calculated according to the thermal resistance distribution rule. The temperature distribution calculation module is used to perform S7:S7, which divides the outbound and return total unit channels into several identical macrocells along the flow direction and constructs a temperature distribution model. The temperature distribution model is constructed by substituting the initial inlet conditions into the first macrocell and taking the outlet temperature of the previous macrocell as the inlet temperature of the next macrocell. S4 to S6 are solved iteratively to obtain the cooling oil temperature distribution, hot air temperature distribution and air sidewall temperature distribution for the outbound and return flows.
[0017] The beneficial effects of this invention are that the performance prediction method for cooling channels provided by this invention achieves high-precision, global prediction of the performance of complex cooling channel systems through a strategy of step-by-step modeling, discrete elements, and iterative calculation. Specifically, it has the following effects: Starting from the most basic physical parameters and local heat transfer coefficients, this method gradually constructs the overall heat transfer coefficient, and finally reveals the macroscopic performance (temperature distribution) of the entire system along the flow direction through discretization and iteration.
[0018] Ultimately, it can output three key performance indicators: cooling oil temperature distribution, hot air temperature distribution, and air sidewall temperature distribution. This provides accurate data support for evaluating heat exchange efficiency, optimizing system design, and ensuring operational safety. It not only presents the overall results for the inlet and outlet, but more importantly, reveals the detailed changes in temperature parameters within the heat exchanger, helping to identify potential hot spots and non-uniformities, and pointing the way for structural optimization. The S7 iterative process integrates all preceding steps into a complete computational chain, ensuring that even minute changes in inlet conditions are propagated and affect the final global distribution, realistically simulating actual operating conditions.
[0019] In summary, this method systematically decomposes complex physical problems into computable steps, ultimately forming a digital simulation tool that can effectively guide the design, verification, and performance evaluation of cooling channels. Attached Figure Description
[0020] Figure 1 is a flowchart of the present invention; Figure 2 is a structural diagram of the cooling channel in the present invention; Figure 3 is one of the structural parameter diagrams of the cooling channel in the present invention; Figure 4 is another structural parameter diagram of the cooling channel in the present invention; Figure 5 is a discrete example diagram of the outgoing cooling oil and hot air unit in the cooling channel in the present invention; Figure 6 is a discrete example diagram of the return cooling oil and hot air unit in the cooling channel in the present invention. Detailed Implementation
[0021] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0022] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.
[0023] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0024] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two elements or the interaction between two elements, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0025] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.
[0026] As shown in Figures 1-6, the present invention provides a method for predicting the performance of a cooling channel, comprising the following steps: S1, determining the basic parameters, which include the structural parameters of the cooling channel side and the air side, the physical property parameters of the hot and cold fluids, and the fluid inlet conditions; this step determines the data basis for the entire calculation model, clarifies the geometric structure of the cooling channel, the physical properties of the working medium, and the boundary conditions of the operation, as the input source for subsequent calculations.
[0027] S2, construct a calculation model for the convective heat transfer coefficients on the hot and cold fluid sides. The calculation model calculates the convective heat transfer coefficients on the cooling fuel side and the hot air side for both the outward and return journeys based on the basic parameters, Reynolds number, Prandtl number, heat transfer factor, and fluid mass flow rate. This step quantifies the local heat transfer capacity between the fluid and the solid wall. By introducing the Reynolds number, Prandtl number, and heat transfer factor, the complex convective heat transfer process is modeled, and the convective heat transfer coefficients on the cooling fuel side and the hot air side for both the outward and return journeys are calculated respectively.
[0028] S3. Construct a model for calculating the overall heat transfer coefficient. This model calculates the overall surface efficiency of the fins on the fluid side, the thermal resistance of the baffles on the outgoing and returning sides, the convective heat transfer coefficients on the cooling oil side, and the convective heat transfer coefficients on the hot air side on the outgoing and returning sides, based on the efficiency coefficients of the cooling fins on the outgoing and returning sides. It then calculates the overall heat transfer coefficients between the cooling oil and hot air on the outgoing and returning sides. This step comprehensively considers thermal resistance to form an overall heat transfer capacity index, integrating the convective heat transfer coefficients, fin efficiency (utilization efficiency of the extended surface), and baffle thermal resistance obtained in S2. This provides necessary parameters for subsequent calculations of the total heat exchange.
[0029] S4 divides the hot and cold fluid regions into an outgoing total unit channel and a returning total unit channel. The outgoing total unit channel is further divided into an outgoing cooling fuel unit channel and an outgoing hot air unit channel, and the returning total unit channel is divided into a returning cooling fuel unit channel and a returning hot air unit channel. Based on the overall heat transfer coefficient, the following is adopted: The method calculates the heat exchange between the outgoing cooling oil and hot air in the outgoing unit channel and the heat exchange between the returning cooling oil and hot air in the returning unit channel. This step discretizes the continuous heat exchange process and calculates the heat exchange of each discrete unit. This is done by dividing the entire flow channel into unit channels and using... The method accurately calculates the actual heat exchanged between hot and cold fluids within each unit.
[0030] S5 constructs a calculation model for the outlet temperatures of the hot and cold fluid units. This model calculates the outlet temperatures of the outgoing cooling fuel unit, the outgoing hot air unit, the returning cooling fuel unit, and the returning hot air unit through the heat exchange between the outgoing and returning cooling oil and hot air. Based on the law of conservation of energy, this step determines the state changes of the fluid after heat exchange in one unit. It uses the heat exchange calculated in S4 to deduce the temperatures of the fuel and air at the outlet of each unit channel, providing new inlet conditions for the heat transfer calculations of downstream units.
[0031] S6, Calculate the outbound and return air sidewall temperatures according to the thermal resistance distribution rules; this step determines the air sidewall temperature. Specifically, the air sidewall temperature is calculated by analyzing the thermal resistance distribution along the heat flow path.
[0032] In step S7, the outbound and return flow channels are divided into several identical macrocells along the flow direction, and a temperature distribution model is constructed. This model substitutes the initial inlet conditions into the first macrocell and sequentially uses the outlet temperature of the previous macrocell as the inlet temperature of the next macrocell, iteratively solving steps S4 to S6 to obtain the cooling oil temperature distribution, hot air temperature distribution, and air sidewall temperature distribution for both the outbound and return flows. This step enables global performance prediction of the entire heat exchanger along the flow direction. By dividing the long flow channel into numerous "macrocells" and performing iterative calculations in series (using the output of the previous cell as the input of the next cell), the continuous distribution of fluid temperature and wall temperature along the entire flow channel is obtained, revealing the evolution of performance.
[0033] The cooling channel performance prediction method provided by this invention achieves high-precision, global prediction of the performance of complex cooling channel systems through a strategy of step-by-step modeling, discrete elements, and iterative calculation. Specifically, it has the following effects: Starting from the most basic physical parameters and local heat transfer coefficients, the method gradually constructs the overall heat transfer coefficient, and finally reveals the macroscopic performance (temperature distribution) of the entire system along the flow direction through discretization and iteration.
[0034] Ultimately, it can output three key performance indicators: cooling oil temperature distribution, hot air temperature distribution, and air sidewall temperature distribution. This provides accurate data support for evaluating heat exchange efficiency, optimizing system design, and ensuring operational safety. It not only presents the overall results for the inlet and outlet, but more importantly, reveals the detailed changes in temperature parameters within the heat exchanger, helping to identify potential hot spots and non-uniformities, and pointing the way for structural optimization. The S7 iterative process integrates all preceding steps into a complete computational chain, ensuring that even minute changes in inlet conditions are propagated and affect the final global distribution, realistically simulating actual operating conditions.
[0035] In summary, this method systematically decomposes complex physical problems into computable steps, ultimately forming a digital simulation tool that can effectively guide the design, verification, and performance evaluation of cooling channels.
[0036] In one embodiment, the temperature distribution model includes: S71, discretizing the outgoing and returning total unit channels into multiple macrocells of equal number along their respective flow directions; wherein the number of macrocells is determined based on the degree of drastic change in the physical properties of the cooling oil during flow and the required computational accuracy; in this step, the total unit channel in S4 is further refined into smaller macrocells, achieving secondary discretization of the flow direction. At this point, determining the number of macrocells is an optimization process that balances computational efficiency and accuracy: regions with drastic changes in physical properties require denser meshes (more macrocells) to capture temperature details, while computational resources limit the infinite refinement of the mesh. This ensures that subsequent iterative calculations achieve the required accuracy within a controllable complexity.
[0037] S72, starting from the first macrocell in the outgoing direction, uses the fluid inlet conditions determined in S1 for the inlet temperatures of the cooling oil and hot air. S4 to S6 are then executed sequentially for this macrocell to calculate its outlet and wall temperatures. This outlet temperature is then used as the inlet temperature of the next adjacent macrocell, and the above calculations are repeated until all macrocells in the outgoing direction are solved, thus obtaining the cooling oil temperature distribution, hot air temperature distribution, and air sidewall temperature distribution in the outgoing direction. This step achieves the relay transfer and distribution calculation of physical parameters in the outgoing direction. Starting from the known inlet conditions, it completes the process of calculating heat transfer, updating the outlet temperature, and calculating the wall temperature within a macrocell, and transmits the outlet state to downstream neighbors. It gradually calculates the temperature distribution along the outgoing direction from the uniform inlet state. It accurately depicts the complete process of cooling oil cooling, hot air heating, and wall temperature changes in the outgoing direction.
[0038] S73, the cooling oil inlet temperature of the first macrocell in the return path is taken from the cooling oil outlet temperature of the last macrocell in the outgoing path calculated in S72; the hot air inlet temperature of this macrocell is the same as the hot air inlet temperature of the first macrocell in the outgoing path in S72. Subsequently, following the same iteration rules as S72, all macrocells in the return path are solved sequentially, ultimately obtaining the cooling oil temperature distribution, hot air temperature distribution, and air sidewall temperature distribution in the return direction. In this step, thermal coupling between the outgoing and return paths is achieved, and the distribution calculation in the return direction is completed. The cooling oil inlet temperature is taken from the end point of the outgoing path, reflecting the continuity of the cooling oil as a continuous medium between the outgoing and return paths. The hot air inlet temperature is still taken from the initial air inlet of the system, clarifying that the outgoing and return paths are in parallel on the air side. Through the same iteration rules, the temperature distributions in the return direction are finally obtained. The performance simulation of all flow channels in the entire cooling channel is completed.
[0039] This embodiment establishes a complete, rigorous, and high-fidelity numerical simulation process. It goes beyond simply acquiring inlet and outlet parameters; it allows for a clear view of temperature changes at every point in the flow channel. Furthermore, it simulates the highly efficient heat exchange between cooling oil and air through near-countercurrent flow. Additionally, by outputting the air sidewall temperature distribution, it can directly pinpoint the hottest areas in the entire system. This is of decisive guiding significance for preventing material failure, avoiding fuel coking, assessing thermal stress, and guiding structural optimization (such as localized enhanced cooling).
[0040] In one embodiment, the adoption The method calculates the heat exchange between the outgoing cooling oil and hot air in the outgoing unit channel and the heat exchange between the returning cooling oil and hot air in the returning unit channel, including a calculation model for the heat exchange of the total unit channel. The calculation model for the heat exchange of the total unit channel is as follows: ; In the formula, ε0 represents the heat exchange between the cooling oil and hot air during the outgoing journey; ε1 represents the outgoing journey heat transfer efficiency; C min T is the product of the minimum specific heat capacity of the hot and cold media and the flow rate; in,air去 T represents the inlet temperature of the outgoing hot air unit. in,冷却油去 This refers to the inlet temperature of the outgoing cooling oil unit. ε2 is the heat exchange between the return cooling oil and the hot air; ε3 is the return heat transfer efficiency; C min T is the product of the minimum specific heat capacity of the hot and cold media and the flow rate; in,air回 T represents the inlet temperature of the return hot air unit. in,冷却油回 This refers to the inlet temperature of the return cooling oil unit.
[0041] In this embodiment, the heat exchange between hot and cold fluids within a single unit channel is directly calculated using the inlet temperature and system characteristics. The introduction of forward and return heat transfer efficiencies in the model eliminates the need for complex iterative calculations of the outlet temperature, simplifying the calculation process and improving numerical stability. The product of the minimum specific heat capacity of the hot and cold media and the flow rate represents the theoretically maximum heat exchange that may occur within the unit channel. The actual heat exchange is the product of this maximum value and the heat transfer efficiency.
[0042] In one embodiment, the outlet temperature calculation model for the hot and cold fluid unit is as follows: ; ; ; In the formula, T out,冷却油去 This refers to the outlet temperature of the outgoing cooling oil unit. The heat exchanged between the cooling oil and hot air during the outward journey; C represents the mass flow rate of the cooling oil. p冷却油去T represents the specific heat capacity of the cooling oil on the outgoing route. in,冷却油去 T represents the inlet temperature of the outgoing cooling oil unit. out,air去 This refers to the outlet temperature of the outgoing hot air unit. This is for the heat exchange between the returning cooling oil and the hot air; C is the mass flow rate of hot air. p热空气去 T is the specific heat capacity of the outgoing hot air; in,air去 T represents the inlet temperature of the outgoing hot air unit. out,冷却油回 T represents the outlet temperature of the return cooling oil unit. in,冷却油回 T represents the inlet temperature of the return cooling oil unit. out,air回 C is the outlet temperature of the return hot air unit. p热空气回 T is the specific heat capacity of the return hot air; in,air回 This refers to the inlet temperature of the return hot air unit.
[0043] In this embodiment, based on the law of conservation of energy, the heat exchange within the unit is accurately converted into fluid temperature changes, thereby determining the fluid thermal state at the outlet of each discrete unit. The outlet temperature calculation model for the hot and cold fluid units is based on the calculated heat exchange. Combined with the mass flow rate of the fluid and specific heat capacity C p It accurately calculates the temperature change of cold and hot fluids after they flow through the unit.
[0044] By using simple algebraic calculations to determine the unit outlet temperature, the outlet temperatures of the cooling oil and air in each unit channel are directly given. This enables a transition from local performance analysis to global system prediction.
[0045] In one embodiment, the structural parameters of the cooling channel side and air side in S1 include: the number of cooling oil fluid channels for the outgoing and returning strokes, the total heat dissipation area, the flow area, the hydraulic diameter, and the secondary heat exchange area of the fins; wherein, the heat dissipation area, flow area, and hydraulic diameter of a single channel are calculated based on the geometric parameters of channel width, fin thickness, fin height, channel length, and channel bottom thickness.
[0046] In one embodiment, in S1, the physical properties of the hot and cold fluids include fluid density, specific heat capacity at constant pressure, thermal conductivity, and dynamic viscosity; the values of the physical properties are determined based on the temperature of the fluid at the inlet of the corresponding flow unit.
[0047] In one embodiment, in S2, the calculation model of the convective heat transfer coefficient on the cold and hot fluid sides includes: first, calculate the Reynolds number based on the fluid mass flow rate, hydraulic diameter, and dynamic viscosity, calculate the Prandtl number based on the specific heat capacity at constant pressure, dynamic viscosity, and thermal conductivity, then calculate the cooling fuel heat transfer factor according to the relationship with the Reynolds number, and calculate the convective heat transfer coefficient on the cooling fuel side according to the convective heat transfer coefficient calculation model on the cooling fuel side by combining the Prandtl number and the cooling fuel heat transfer factor, and calculate the convective heat transfer coefficients on the hot air sides of the forward and return trips according to the convective heat transfer coefficient calculation models on the hot air sides of the forward and return trips; the convective heat transfer coefficient calculation model on the cooling fuel side is: ; where j is the cooling fuel heat transfer factor; C P is the specific heat capacity at constant pressure; M is the mass flow rate of the cold and hot side fluids; Pr is the Prandtl number of the cold and hot fluids; i = 1, 2; 1 is the forward trip cooling channel side, 2 is the return trip cooling channel side; the convective heat transfer coefficient calculation models on the hot air sides of the forward and return trips are: ; ; where is the thermal conductivity; De is the hydraulic diameter; air_forward is the forward trip air side; air_return is the return trip air side.
[0048] This convective heat transfer coefficient calculation model on the cooling fuel side can efficiently calculate the heat transfer coefficient inside the channel for the cooling fuel side. For the hot air side, it can accurately calculate the heat transfer coefficient of complex external channels such as fins. The model clearly distinguishes between the forward and return trips and the air side and the fuel side, considering that they may be in different flow states or have different geometric characteristics, and thus calculates them separately, ensuring the accuracy of the calculation.
[0049] In one embodiment, the total heat transfer coefficient calculation model is: ; ; where K1 is the total heat transfer coefficient between the forward trip cooling oil and the hot air; A1 is the heat dissipation area of a single forward trip cooling oil channel; h1 is the convective heat transfer coefficient on the forward trip cooling fuel side; is the total fin surface efficiency on the forward trip fluid side; R w is the partition heat resistance; h air去 is the convective heat transfer coefficient on the forward trip hot air side; A air去 is the heat dissipation area of the hot air side matching the forward trip cooling oil channel: K2 is the total heat transfer coefficient between the return trip cooling oil and the hot air; A2 is the heat dissipation area of a single return trip cooling oil channel; h2 is the convective heat transfer coefficient on the return trip cooling fuel side; is the total fin surface efficiency on the return trip fluid side; h air回 is the convective heat transfer coefficient on the return trip hot air side; A air回 is the heat dissipation area of the hot air side matching the return trip cooling oil channel.
[0050] This overall heat transfer coefficient calculation model considers the resistance that heat must overcome to transfer from the hot fluid (air) to the cold fluid (cooling oil), namely the air-side convective thermal resistance, the baffle thermal resistance, and the fuel-side convective thermal resistance. The model ultimately calculates a simple performance parameter—the overall heat transfer coefficient—which intuitively reflects the ease of heat transfer between the hot and cold fluids within the unit. By introducing the total efficiency of the fin surface, the model corrects for the actual average heat transfer temperature difference loss caused by the fin thermal conductivity resistance, making the calculation results closer to engineering realities.
[0051] In one embodiment, the thermal resistance of the partition is calculated using a partition thermal resistance calculation model: the partition thermal resistance calculation model is as follows: ; In the formula, R w去 For the outgoing flow partition thermal resistance; R w回 For the return baffle thermal resistance; The thickness of the groove bottom; The thermal conductivity of the partition; This refers to the heat dissipation area on the outgoing hot air side; This refers to the heat dissipation area on the return hot air side.
[0052] This invention also provides a specific implementation of a cooling channel performance prediction method, specifically including: S1, the structural parameters of the cooling channel side and air side include: referring to Figures 2-4, the cooling channel structural parameters used in the cooling channel performance prediction method include the number of fluid channels for the cooling oil in the outgoing and returning directions of the cooling channel. and Total heat dissipation area of cooling oil fluid on the outgoing route Total heat dissipation area of return cooling oil fluid Total heat dissipation area of outgoing hot air fluid Total heat dissipation area of return hot air fluid Outbound cooling oil fluid flow area Return cooling oil fluid flow area Outbound hot air fluid flow area and return hot air fluid flow area Circulation area ; outgoing cooling oil fluid hydraulic diameter , return cooling oil fluid hydraulic diameter Outbound hot air fluid hydraulic diameter and return hot air fluid hydraulic diameter ; and the secondary heat exchange area of the outgoing fins. and the secondary heat exchange area of the return fins The calculation formulas for each parameter are as follows: The heat dissipation area of a single outgoing cooling oil channel is: The heat dissipation area of a single return-flow cooling oil channel is: The hot air side heat dissipation area matched with the cooling oil channel is: ; The outbound cooling oil channel flow area is: The return cooling oil channel flow area is: The hot air circulation area is consistent with the circulation area of the outgoing and returning cooling channels.
[0053] The hydraulic diameter of the outgoing cooling oil channel is: The hydraulic diameter of the return cooling oil channel is: The hydraulic diameter of the hot air is the same as the hydraulic diameter of the outgoing cooling oil channel and the hydraulic diameter of the return cooling channel.
[0054] The secondary heat exchange areas of the outgoing fins and the returning fins are: In the above formulas, (i=1,2, air to, air back. 1 is the outgoing cooling duct side, 2 is the returning cooling duct side, air to is the outgoing air side, air back is the returning air side), where: Width of the cooling channel (mm). The thickness of the rib is (mm). L represents the rib height (mm) and L represents the channel length (mm). The hydraulic diameter is (m). Heat dissipation area (m²) 2 ), For circulation area (m 2 ), For finned heat exchange area (m²) 2 ).
[0055] In S1, the physical properties of the hot and cold fluids include: the selection of fluid physical properties includes fluid density. Specific heat capacity at constant pressure thermal conductivity Dynamic viscosity Since the physical properties of a fluid change with its temperature, this invention selects the fluid's properties at its inlet temperature as the computational properties of the model. The hot fluid used in this invention is hot air, and the cold fluid is cooling fuel oil. Their physical properties change with temperature as follows: Physical property parameters of hot air: Specific heat capacity at constant pressure: The dynamic viscosity is: The thermal conductivity is: The air density is: ; The pressure of the incoming airflow.
[0056] Cooling fuel physical properties: Specific heat capacity at constant pressure is: The kinematic viscosity is: The thermal conductivity is: The density is: ; in the above formula This represents the inlet temperature of the fluid.
[0057] In S2, the convective heat transfer coefficients on the hot and cold fluid sides are calculated as follows: the convective heat transfer coefficients between hot air and the air-side wall and between cooling oil and the cooling channel side wall, expressed as Reynolds number. Planck number and heat transfer factor Factors, and combined with fluid mass flow rate The fluid properties (i=1,2, air_out, air_back. 1 represents the outgoing cooling channel side, 2 represents the returning cooling channel side, air_out represents the outgoing air side, and air_back represents the returning air side) are solved. The calculation formulas for each parameter are as follows: The mass flow rates of the hot and cold side fluids are: The Reynolds numbers for the hot and cold side fluids are: The Prandtl number for hot and cold fluids is: ; In the above formula, The mass flow rate of the hot and cold fluids.
[0058] The expression for the heat transfer factor j of cooling fuel is: The calculation model for the convective heat transfer coefficient on the cooling fuel side is as follows: At this point, the calculation model for the convective heat transfer coefficients of the outbound and return hot air sides is as follows: ; In S3, the total heat transfer coefficient refers to the calculation of the total heat transfer coefficient K, which includes: total heat transfer refers to all heat transfer methods between cooling fuel and hot air, including convective heat transfer on the cooling fuel side, heat conduction between baffles and convective heat transfer on the hot air side. The total heat transfer coefficient is used to represent the magnitude of its heat transfer capacity. The formula for calculating the total heat transfer coefficient is as follows: the outbound and return cooling channels have fin efficiency coefficients.
[0059] The fin efficiency is: In the formula, the parameter S is: The overall efficiency of the fin surface on the fluid side is: The thermal resistances of the outbound and return baffles are: ; In the formula, — Thermal conductivity of the partition.
[0060] At this point, the overall heat transfer coefficient calculation model is: the overall heat transfer coefficient between the outgoing cooling oil and the hot air. for: The overall heat transfer coefficient between the return cooling oil and hot air for: In S4, the calculation of heat transfer between hot and cold fluid units includes: heat transfer between cooling fuel and hot air is considered to occur within two main unit channels (outbound unit, return unit). Each main unit channel can be further divided into a cooling fuel unit and a hot air unit. This means the hot and cold fluid regions are divided into an outbound main unit channel and a return main unit channel. The outbound main unit channel is further divided into an outbound cooling fuel unit channel and an outbound hot air unit channel, and the return main unit channel is further divided into a return cooling fuel unit channel and a return hot air unit channel. The method calculates the heat transfer between the cooling fuel unit and the hot air unit (i=1 and 2, 1 represents the outbound trip, 2 represents the return trip). The calculation process is as follows: Number of efficiency units: Heat dissipation efficiency: ; In the above formula, ; ; At this point, the total unit channel heat exchange calculation model is as follows: the heat exchange between the outgoing cooling oil and the hot air is: The heat exchange between the return cooling oil and the hot air is: ;in, The inlet temperature of the outgoing hot air unit. This refers to the inlet temperature of the return hot air unit. This refers to the inlet temperature of the outgoing cooling oil unit. This refers to the inlet temperature of the return cooling oil unit. It is the product of the minimum specific heat capacity of the hot and cold media and the flow rate, where the flow rate is the mass flow rate of the corresponding fluid medium. For heat transfer efficiency.
[0061] In S5, the calculation of the outlet temperature of the hot and cold fluid unit includes: after obtaining the heat exchange between the cooling fuel unit and the hot air unit, the outlet temperature of the hot and cold fluid unit is calculated using the outlet temperature calculation model of the hot and cold fluid unit. The outlet temperature calculation model of the hot and cold fluid unit is as follows: The outlet temperatures of the outbound hot and cold fluids are respectively: ; The outlet temperatures of the return hot and cold fluids are respectively: ; In S6, according to the thermal resistance distribution rule, the calculation of the outbound air sidewall temperature and the return air sidewall temperature includes: The calculation of the outbound and return air sidewall temperatures follows the thermal resistance distribution rule, and the calculation formula is: Outbound air sidewall temperature Return air sidewall temperature In S7, the discrete calculations of cooling fuel temperature, hot air temperature, and air sidewall temperature include: The heat transfer calculation between the outgoing cooling oil and hot air is referenced in Figure 5. The outgoing unit is divided into j identical macro-units along the flow direction. The number of macro-units is determined by the degree of change in cooling oil properties and the computational solver capability. Within each macro-unit, there are outgoing cooling oil units and outgoing hot air units. The overall heat transfer coefficient mentioned above is used. The calculation rule is derived from The heat exchange within a macrocell can be calculated.
[0062] In the model for calculating the outlet temperature of the hot and cold fluid units: ; The cooling oil temperature and hot air temperature at the macrocell outlet can be obtained by inverse solving, and the air sidewall temperature calculation formula can be used: Wall temperature calculations can be performed.
[0063] Referring to Figure 6, the aforementioned return unit is divided into j identical macrocells along the flow direction. The number of macrocells is determined by the degree of change in the cooling oil properties and the computational solution capability. Each macrocell is further divided into a return cooling oil unit and a return hot air unit, using the aforementioned overall heat transfer coefficient and... The calculation rule is derived from The heat exchange within a macrocell can be calculated.
[0064] In the model for calculating the outlet temperature of the hot and cold fluid units: ; The cooling oil temperature and hot air temperature at the macrocell outlet can be obtained by inverse solving, and the air sidewall temperature can be calculated using the formula. Wall temperature calculations can be performed.
[0065] It is important to note that the above calculation rules and assumptions are as follows: 1. The hot fluid is assumed to be uniformly distributed within the macrocell; 2. The velocity of the hot fluid within a single channel is assumed to be uniformly distributed, ignoring the non-uniformity of the flow field within the pipe; 3. The properties of the hot fluid are assumed to be stable and uniformly distributed within each computational unit; 4. The specific heat capacity is assumed to be a physical property parameter in the hot and cold fluid macrocells. Dynamic viscosity Thermal conductivity Fluid density middle The inlet temperature of the macrocell is used for calculation. This represents the heat exchange area of the macrocell. The cooling oil temperature and hot air temperature at the inlet of the next macrocell are equal to the cooling oil temperature and hot air temperature at the outlet of the previous macrocell.
[0066] This invention also provides a performance prediction system for cooling channels, comprising: a basic parameter determination module, used for S1:S1, determining basic parameters, including structural parameters of the cooling channel side and air side, physical property parameters of hot and cold fluids, and fluid inlet conditions; a hot and cold fluid side convective heat transfer coefficient calculation module, used for S2:S2, constructing a calculation model for the hot and cold fluid side convective heat transfer coefficient, wherein the calculation model calculates the convective heat transfer coefficient of the cooling fuel side and the convective heat transfer coefficients of the outbound and return hot air sides based on the basic parameters, Reynolds number, Prandtl number, heat transfer factor, and combined with the fluid mass flow rate; and a total heat transfer coefficient calculation module, used for S3:S3, constructing the total heat transfer coefficient. The coefficient calculation model calculates the overall heat transfer coefficient based on the fluid-side fin surface efficiency, outgoing and returning baffle thermal resistance, cooling fuel side convective heat transfer coefficient, and outgoing and returning hot air side convective heat transfer coefficient. It then calculates the overall heat transfer coefficient between the outgoing cooling oil and hot air, and between the returning cooling oil and hot air. The heat transfer calculation module performs S4:S4, dividing the hot and cold fluid regions into an outgoing total unit channel and a returning total unit channel. The outgoing total unit channel is further divided into an outgoing cooling fuel unit channel and an outgoing hot air unit channel, and the returning total unit channel is divided into a returning cooling fuel unit channel and a returning hot air unit channel. Based on the overall heat transfer coefficient, it uses... The method calculates the heat exchange between the outgoing cooling oil and hot air in the outgoing main unit channel and the heat exchange between the returning cooling oil and hot air in the returning main unit channel; the heat exchange calculation module is used to perform S5:S5, constructing a calculation model for the outlet temperature of the cold and hot fluid units. The outlet temperature calculation model of the cold and hot fluid units calculates the outlet temperature of the outgoing cooling fuel unit channel, the outlet temperature of the outgoing hot air unit channel, the outlet temperature of the returning cooling fuel unit channel, and the outlet temperature of the returning hot air unit channel based on the heat exchange between the outgoing cooling oil and hot air and the returning cooling oil and hot air; the air side wall temperature calculation module uses... In S6:S6, the outbound air sidewall temperature and the return air sidewall temperature are calculated according to the thermal resistance distribution rule. The temperature distribution calculation module is used to perform S7:S7, which divides the outbound and return total unit channels into several identical macrocells along the flow direction and constructs a temperature distribution model. The temperature distribution model is constructed by substituting the initial inlet conditions into the first macrocell and taking the outlet temperature of the previous macrocell as the inlet temperature of the next macrocell. S4 to S6 are solved iteratively to obtain the cooling oil temperature distribution, hot air temperature distribution and air sidewall temperature distribution for the outbound and return flows.
[0067] The above description is merely an embodiment and does not constitute any limitation on the present invention. Any person skilled in the art can make many possible variations, modifications, or alterations to the technical solutions of the present invention without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the present invention, should fall within the protection scope of the present invention.
Claims
1. A method for predicting the performance of cooling channels, characterized in that, Includes the following steps: S1. Determine the basic parameters, which include the structural parameters of the cooling channel side and the air side, the physical properties of the hot and cold fluids, and the fluid inlet conditions. S2, Construct a calculation model for the convective heat transfer coefficients on the hot and cold fluid sides. This model calculates the convective heat transfer coefficients on the cooling fuel side and the outgoing and returning hot air sides based on fundamental parameters, Reynolds number, Prandtl number, heat transfer factor, and fluid mass flow rate. S3, Construct a calculation model for the overall heat transfer coefficient. This model calculates the overall heat transfer coefficient between the cooling oil and hot air sides based on the overall efficiency of the fin surface on the fluid side (calculated using the outgoing and returning cooling fin efficiency coefficients), the thermal resistance of the baffles on the outgoing and returning sides, the convective heat transfer coefficients on the cooling fuel side, and the convective heat transfer coefficients on the outgoing and returning hot air sides. S4, Divide the hot and cold fluid regions into outgoing and returning total unit channels. The outgoing total unit channel is further divided into an outgoing cooling fuel unit channel and an outgoing hot air unit channel. The returning total unit channel is divided into a returning cooling fuel unit channel and a returning hot air unit channel. Based on the overall heat transfer coefficient, a calculation model is adopted... The following steps are performed: S5, constructing a model for calculating the outlet temperatures of the cold and hot fluid units. This model calculates the outlet temperatures of the cold and hot fluid units based on the heat exchange between the cold and hot fluid units and the return cooling oil and hot air. S6, calculating the outlet temperatures of the cold and hot fluid units based on the heat exchange between the cold and hot fluid units and the return cooling oil and hot air. S7, dividing the cold and hot fluid units into several identical macrocells along the flow direction, constructing a temperature distribution model. This model substitutes the initial inlet conditions into the first macrocell and uses the outlet temperature of the previous macrocell as the inlet temperature of the next macrocell. S8 iteratively solves steps S4 to S6 to obtain the temperature distributions of the cold and hot fluid units for both the cold and hot fluid units.
2. The performance prediction method for cooling channels as described in claim 1, characterized in that, The temperature distribution model includes: S71, discretizing the outbound and return macrocell channels into multiple macrocells of equal number along their respective flow directions; S72, starting from the first macrocell in the outbound direction, the inlet temperatures of its cooling oil and hot air are determined using the fluid inlet conditions determined in S1; S4 to S6 are executed sequentially for this macrocell to calculate its outlet temperature and wall temperature; this outlet temperature is used as the inlet temperature of the next adjacent macrocell, and the above calculation is repeated until all macrocells in the outbound direction are solved, thereby obtaining the cooling oil temperature distribution, hot air temperature distribution, and air sidewall temperature distribution in the outbound direction; S73, the cooling oil inlet temperature of the first macrocell in the return direction is taken from the cooling oil outlet temperature of the last macrocell in the outbound direction calculated in S72; the hot air inlet temperature of this macrocell is the same as the hot air inlet temperature of the first macrocell in the outbound direction in S72; thereafter, following the same iteration rules as S72, all macrocells in the return direction are solved sequentially to finally obtain the cooling oil temperature distribution, hot air temperature distribution, and air sidewall temperature distribution in the return direction.
3. The performance prediction method for cooling channels as described in claim 1, characterized in that, The use The method calculates the heat exchange between the outgoing cooling oil and hot air in the outgoing unit channel and the heat exchange between the returning cooling oil and hot air in the returning unit channel, including a calculation model for the heat exchange of the total unit channel. The calculation model for the heat exchange of the total unit channel is as follows: ; In the formula, ε is the heat exchange between the cooling oil and hot air on the outgoing route; ε1 is the outgoing route heat transfer efficiency. It is the product of the minimum specific heat capacity of the hot and cold media and the flow rate; This refers to the inlet temperature of the outgoing hot air unit. This refers to the inlet temperature of the outgoing cooling oil unit. ε2 is the heat exchange between the return cooling oil and the hot air; ε3 is the return heat transfer efficiency; C min T is the product of the minimum specific heat capacity of the hot and cold media and the flow rate; in,air回 T represents the inlet temperature of the return hot air unit. in,冷却油回 This refers to the inlet temperature of the return cooling oil unit.
4. The performance prediction method for cooling channels as described in claim 1, characterized in that, The outlet temperature calculation model for the hot and cold fluid unit is as follows: ; ; ; In the formula, T out,冷却油去 This refers to the outlet temperature of the outgoing cooling oil unit. The heat exchanged between the cooling oil and hot air during the outward journey; C represents the mass flow rate of the cooling oil. p冷却油去 T represents the specific heat capacity of the cooling oil on the outgoing route. in,冷却油去 T represents the inlet temperature of the outgoing cooling oil unit. out,air去 This refers to the outlet temperature of the outgoing hot air unit. For the heat exchange between the returning cooling oil and the hot air, C is the mass flow rate of hot air. p热空气去 T is the specific heat capacity of the outgoing hot air; in,air去 T represents the inlet temperature of the outgoing hot air unit. out,冷却油回 T represents the outlet temperature of the return cooling oil unit. in,冷却油回 T represents the inlet temperature of the return cooling oil unit. out,air回 C is the outlet temperature of the return hot air unit. p热空气回 T is the specific heat capacity of the return hot air; in,air回 This refers to the inlet temperature of the return hot air unit.
5. The performance prediction method for cooling channels as described in claim 1, characterized in that, In S1, the structural parameters of the cooling channel side and the air side include: the number of cooling oil fluid channels in the outgoing and returning directions, the total heat dissipation area, the flow area, the hydraulic diameter, and the secondary heat exchange area of the fins; wherein, the heat dissipation area, flow area, and hydraulic diameter of a single channel are calculated based on the geometric parameters of channel width, fin thickness, fin height, channel length, and channel bottom thickness.
6. The performance prediction method for cooling channels as described in claim 1, characterized in that, In S1, the physical properties of the hot and cold fluids include fluid density, specific heat capacity at constant pressure, thermal conductivity, and dynamic viscosity; the values of these physical properties are determined based on the temperature of the fluid at the inlet of the corresponding flow unit.
7. The performance prediction method for cooling channels according to claim 1, characterized in that, In S2, the calculation model for the convective heat transfer coefficient on the hot and cold fluid sides includes: first, calculating the Reynolds number based on the fluid mass velocity, hydraulic diameter, and dynamic viscosity; then, calculating the Prandtl number based on the specific heat capacity at constant pressure, dynamic viscosity, and thermal conductivity; next, calculating the cooling fuel heat transfer factor based on the relationship with the Reynolds number; finally, calculating the cooling fuel convective heat transfer coefficient based on the calculation model using the Prandtl number and the cooling fuel heat transfer factor; and finally, calculating the convective heat transfer coefficients on the hot air sides for both the outbound and return journeys using the same calculation model. The calculation model for the cooling fuel convective heat transfer coefficient is as follows: In the formula, j is the heat transfer factor of the cooling fuel; C P Where is the specific heat capacity at constant pressure; M is the mass flow rate of the fluid on the hot and cold sides; Pr is the Prandtl number of the hot and cold fluids; i = 1, 2; 1 is the outgoing cooling channel side, and 2 is the return cooling channel side; the calculation model for the convective heat transfer coefficient of the outgoing and return hot air sides is as follows: ; In the formula, λ is the thermal conductivity; De is the hydraulic diameter; air_out is the air side of the outgoing process; air_back is the air side of the return process.
8. The performance prediction method for cooling channels according to claim 1, characterized in that, The overall heat transfer coefficient calculation model is as follows: ; In the formula, K1 is the total heat transfer coefficient between the outgoing cooling oil and the hot air; A1 is the heat dissipation area of a single outgoing cooling oil channel; and h1 is the convective heat transfer coefficient of the outgoing cooling fuel side. 01 R represents the total efficiency of the fin surface on the outgoing fluid side; w For the thermal resistance of the partition; h air去 A is the convective heat transfer coefficient on the outgoing hot air side; air去 The heat dissipation area on the hot air side matched with the outgoing cooling oil channel: K2 is the total heat transfer coefficient between the return cooling oil and hot air; A2 is the heat dissipation area of a single return cooling oil channel; h2 is the convective heat transfer coefficient on the return cooling fuel side. 02 h represents the total efficiency of the fin surface on the return fluid side. air回 A is the convective heat transfer coefficient on the return hot air side; air回 The heat dissipation area on the hot air side is matched with the return flow and the cooling oil channel.
9. The performance prediction method for cooling channels according to claim 8, characterized in that, The thermal resistance of the partition is calculated using a partition thermal resistance calculation model: The partition thermal resistance calculation model is as follows: ; In the formula, R w去 For the outgoing flow partition thermal resistance; R w回 For the return baffle thermal resistance; The thickness of the groove bottom; The thermal conductivity of the partition; This refers to the heat dissipation area on the outgoing hot air side; This refers to the heat dissipation area on the return hot air side.
10. A performance prediction system for cooling channels, characterized in that, include: The basic parameter determination module is used for S1:S1, determining the basic parameters, which include the structural parameters of the cooling channel side and the air side, the physical property parameters of the hot and cold fluids, and the fluid inlet conditions; the hot and cold fluid side convective heat transfer coefficient calculation module is used for S2:S2, constructing a calculation model for the hot and cold fluid side convective heat transfer coefficient. The calculation model calculates the convective heat transfer coefficient of the cooling fuel side and the convective heat transfer coefficient of the outbound and return hot air sides based on the basic parameters, Reynolds number, Prandtl number, heat transfer factor, and fluid mass flow rate. The overall heat transfer coefficient calculation module is used to perform S3:S3 and construct an overall heat transfer coefficient calculation model. The overall heat transfer coefficient calculation model calculates the overall efficiency of the fin surface on the fluid side, the thermal resistance of the baffle on the outgoing and returning sides, the convective heat transfer coefficient on the cooling fuel side, and the convective heat transfer coefficient on the hot air side on the outgoing and returning sides based on the efficiency coefficients of the outgoing and returning cooling fins. It then calculates the overall heat transfer coefficient between the outgoing cooling oil and the hot air, as well as the overall heat transfer coefficient between the returning cooling oil and the hot air. The heat transfer calculation module is used for S4:S4, which divides the hot and cold fluid regions into outgoing and return total unit channels. The outgoing total unit channel is further divided into outgoing cooling fuel unit channel and outgoing hot air unit channel, and the return total unit channel is divided into return cooling fuel unit channel and return hot air unit channel. Based on the overall heat transfer coefficient, it uses... The method calculates the heat exchange between the outgoing cooling oil and hot air in the outgoing main unit channel and the heat exchange between the returning cooling oil and hot air in the returning main unit channel; the heat exchange calculation module is used to perform S5:S5, constructing a calculation model for the outlet temperature of the cold and hot fluid units. The outlet temperature calculation model of the cold and hot fluid units calculates the outlet temperature of the outgoing cooling fuel unit channel, the outlet temperature of the outgoing hot air unit channel, the outlet temperature of the returning cooling fuel unit channel, and the outlet temperature of the returning hot air unit channel based on the heat exchange between the outgoing cooling oil and hot air and the returning cooling oil and hot air; the air side wall temperature calculation module uses... In S6:S6, the outbound air sidewall temperature and the return air sidewall temperature are calculated according to the thermal resistance distribution rule. The temperature distribution calculation module is used to perform S7:S7, which divides the outbound and return total unit channels into several identical macrocells along the flow direction and constructs a temperature distribution model. The temperature distribution model is constructed by substituting the initial inlet conditions into the first macrocell and taking the outlet temperature of the previous macrocell as the inlet temperature of the next macrocell. S4 to S6 are solved iteratively to obtain the cooling oil temperature distribution, hot air temperature distribution and air sidewall temperature distribution for the outbound and return flows.
Citation Information
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