Evaluation method, evaluation program, and evaluation device

Abstract

Regarding evaluation methods, evaluation programs, and evaluation devices, the aim is to accurately understand the effect of thermal convection from multiple heat sources on a single target component. [Solution] The disclosed evaluation method estimates parameters related to the surface temperature of each heat source in a model space that includes multiple heat sources and a target component. A virtual substance having a concentration corresponding to the parameter is set on the surface of each heat source, and a simulation is performed in which the virtual substance diffuses and conves from the surface of each heat source while fixing the velocity field and temperature field in the model space. Furthermore, the attained concentration, which is the concentration of the virtual substance that reaches the surface of the target component, is estimated for each heat source, and the ratio of the attained concentrations from each heat source is calculated as the influence ratio of thermal convection.

Description

[Technical Field]

[0001] This paper relates to an evaluation method, evaluation program, and evaluation apparatus for quantitatively evaluating the influence of thermal convection from multiple heat sources on a single target component. [Background technology]

[0002] In temperature analysis of automobiles and other vehicles equipped with heat source devices, a method is known for evaluating the thermal effects of the heat source on various components in the engine compartment using thermal fluid analysis software. For example, Patent Document 1 discloses a technique for determining the temperature distribution by arranging a virtual heat transfer medium around the heat source in the analysis model and calculating the temperature of the heat transfer medium that receives heat transfer from the heat source (see Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2016-146031 [Overview of the project] [Problems that the invention aims to solve]

[0004] Existing methods make it difficult to accurately determine the proportion of thermal influence each heat source has on a single component when multiple heat sources are present. For example, the amount of heat transferred by conduction can be determined mainly based on the distance between the heat source and the component. However, the amount of heat transferred by convection is affected by the overall flow of the gas heated by the heat source, and therefore cannot be determined solely based on the distance between the component and the heat source. As a result, for example, when considering the placement of a heat shield to prevent the temperature rise of a component, it is difficult to identify the position of the heat shield that will most effectively suppress the temperature rise of the component. Furthermore, when re-examining the heat output and placement of each heat source, it is difficult to identify which heat source has the strongest influence on the temperature rise of the component.

[0005] One of the objectives of this invention is to provide an evaluation method, evaluation program, and evaluation apparatus that can accurately grasp the effect of thermal convection from multiple heat sources to a single target component, in light of the problems described above. Furthermore, in addition to this objective, another objective of this invention is to achieve effects and benefits derived from the various configurations shown in the "Modes for Carrying Out the Invention" section below, which cannot be obtained with conventional technology. [Means for solving the problem]

[0006] The disclosed evaluation method, evaluation program, and evaluation apparatus can be implemented in the following embodiments (application examples) and solve at least some of the above-mentioned problems. Embodiments 1 to 9 relate to the evaluation method. Embodiments 2 to 9 are all embodiments that can be optionally selected and all are optional. Embodiments 2 to 9 do not disclose any embodiments or configurations that are essential to this case. Embodiment 10 relates to the evaluation program, and Embodiment 11 relates to the evaluation apparatus. Embodiments 10 and 11 can be modified to include configurations corresponding to Embodiments 2 to 9.

[0007] Embodiment 1. An evaluation method for the disclosure is an evaluation method for quantitatively evaluating the influence ratio of thermal convection from multiple heat sources to a single target component using thermal fluid analysis software, comprising: a first step of estimating parameters related to the surface temperature of each heat source in a model space including the multiple heat sources and the target component; a second step of setting a virtual substance having a concentration corresponding to the parameter on the surface of each heat source; a third step of fixing the velocity field and temperature field in the model space and performing a simulation of the virtual substance diffusing and convection from the surface of each heat source; a fourth step of estimating the attained concentration, which is the concentration of the virtual substance that has reached the surface of the target component, for each heat source; and a fifth step of calculating the ratio of the attained concentrations from each heat source as the influence ratio.

[0008] Aspect 2. Regarding the aspect including the above Aspect 1, it is preferable that the parameter is a reference temperature calculated as the difference between the average temperature on the surface of each heat source and the air temperature. Aspect 3. Regarding the aspect including the above Aspect 1, it is preferable that the parameter is the amount of heat on the surface of each heat source. Aspect 4. Regarding the aspect including the above Aspect 1, it is preferable that the parameter is the heat flux on the surface of each heat source.

[0009] Aspect 5. Regarding the aspect including the above Aspect 1, it is preferable that the evaluation method includes a sixth step of outputting the influence ratio for each heat source to an output device. Aspect 6. Regarding the aspect including the above Aspect 1, it is preferable that the evaluation method includes a seventh step of outputting an isosurface of a predetermined concentration as a three-dimensional image to an output device based on the concentration distribution of the virtual substance in the model space.

[0010] Aspect 7. Regarding the aspect including the above Aspect 1, it is preferable that the target part has a surface temperature below the temperature of the air adjacent to the target part. Alternatively, it is preferable that the target part has a surface temperature below the value obtained by adding a positive predetermined value to the temperature of the air adjacent to the target part. In other words, it is preferable that the target part is a part that is not greatly affected by heat radiation and heat conduction, and is a part that is easily affected by heat convection.

[0011] Aspect 8. Regarding the aspect including the above Aspect 1, it is preferable that the heat source includes two or more of an engine, a supercharger, a catalytic converter, a transmission, and a heat exchanger mounted on an automobile. In other words, it is preferable that the heat source includes two or more of an internal combustion engine and its accessory devices mounted on an automobile.

[0012] Embodiment 9. With respect to embodiments including Embodiment 1 described above, it is preferable that the target component is a power transmission system component mounted on an automobile. In other words, it is preferable that the target component is not an internal combustion engine and its auxiliary devices. The power transmission system component is preferably, for example, a propeller shaft or joint.

[0013] Embodiment 10. The disclosed evaluation program is an evaluation program for quantitatively evaluating the influence ratio of thermal convection from multiple heat sources to a single target component using thermal fluid analysis software, and causes a computer to execute the following steps: first step of estimating parameters related to the surface temperature of each of the heat sources in a model space including the multiple heat sources and the target component; second step of setting a virtual substance having a concentration corresponding to the parameter on the surface of each of the heat sources; third step of fixing the velocity field and temperature field in the model space and performing a simulation of the virtual substance diffusing and convecting from the surface of each of the heat sources; fourth step of estimating the attained concentration, which is the concentration of the virtual substance that has reached the surface of the target component, for each of the heat sources; and fifth step of calculating the ratio of the attained concentrations from each of the heat sources as the influence ratio.

[0014] Embodiment 11. The disclosed evaluation device is an evaluation device that uses thermal fluid analysis software to quantitatively evaluate the influence ratio of thermal convection from multiple heat sources to a single target component, wherein in a model space including the multiple heat sources and the target component, parameters related to the surface temperature of each heat source are estimated, a virtual substance having a concentration corresponding to the parameter is set on the surface of each heat source, the velocity field and temperature field in the model space are fixed, and a simulation is performed in which the virtual substance diffuses and conves from the surface of each heat source, the reached concentration, which is the concentration of the virtual substance that reaches the surface of the target component, is estimated for each heat source, and the ratio of the reached concentrations from each heat source is calculated as the influence ratio. [Effects of the Invention]

[0015] According to the disclosed technology, a virtual substance is set on the surface of each heat source in the model space, and a simulation is performed in which the virtual substance diffuses and conves from the surface of each heat source. The ratio of the arriving concentrations of the virtual substance is calculated as the influence ratio of thermal convection. This makes it possible to accurately understand the influence of thermal convection from multiple heat sources on a single target component (which heat source is most likely to have a thermal convection influence on the target component). [Brief explanation of the drawing]

[0016] [Figure 1] This is a block diagram of the evaluation system related to the evaluation device. [Figure 2] This diagram illustrates the model space that is analyzed by thermal fluid analysis software. [Figure 3] This is a flowchart showing the evaluation method. [Figure 4] This figure illustrates the temperature distribution in the model space. [Figure 5] This graph shows the calculated results and reference values ​​for the influence of thermal convection. [Figure 6] This figure illustrates isosurfaces at predetermined concentrations of a hypothetical substance diffused from the surface of a supercharger. [Modes for carrying out the invention]

[0017] The disclosed evaluation method, evaluation program, and evaluation apparatus are used to quantitatively evaluate the influence ratio of thermal convection from multiple heat sources to a single target component using thermal fluid analysis software. The multiple heat sources and the single target component can be provided in any system and apparatus. The disclosed evaluation method, evaluation program, and evaluation apparatus can be suitably applied to, for example, automobiles, motorcycles, ships, aircraft, spacecraft, power generation facilities, etc. However, the systems and apparatus to which this disclosure applies are not limited to these.

[0018] In the following embodiments, multiple heat sources and target components are assumed to be mounted on the automobile. Specific examples of heat sources include engines (internal combustion engines), superchargers, exhaust pipes, EGR piping, catalytic converters for exhaust gas purification, exhaust silencers, heat exchangers, transmissions, transaxles, traction motors, inverters, and traction batteries. Specific examples of target components include those included in the heat sources mentioned above, as well as power transmission system components (propeller shafts, joints, differentials, axles, wheels) and auxiliary equipment (fuel pumps, fuel filters, engine oil pumps, engine oil filters, engine coolant pumps, engine coolant filters).

[0019] The method, program, and apparatus according to this embodiment are suitable for quantitatively evaluating the influence of thermal convection when there are multiple heat sources with different heat generation amounts around a single target component, or when the air (gas) flow in the space containing the heat sources and the target component is complex. Furthermore, the method, program, and apparatus according to this embodiment can be suitably used when the target component is considered to be not significantly affected by thermal radiation and thermal conduction, or when it is considered to be a component that is easily affected by thermal convection. [Examples]

[0020] [1. Evaluation device] Figure 1 is a block diagram of the evaluation system 1 according to the present invention. The evaluation system 1 comprises at least an evaluation device 2, and preferably further comprises an output device 5 and an input device 6. Evaluation device 2 is, for example, a general-purpose computer or workstation. Evaluation device 2 includes a processor, memory, and external storage device (not shown). The processor can read a program stored in the external storage device into memory and execute it.

[0021] The external storage device of the evaluation device 2 has the thermal fluid analysis software 3 and the evaluation program 4 installed. The thermal fluid analysis software 3 is a simulation program that estimates and simulates the state and motion of fluids in a three-dimensional model space. The thermal fluid analysis software 3 is also called CFD (Computational Fluid Dynamics) analysis software. The thermal fluid analysis software 3 has the function of calculating the temperature distribution, velocity distribution, pressure distribution, density distribution, etc. of the fluid, taking into account the temperature field, velocity field (flow field), etc. of the fluid in the model space. In this embodiment, the model space including the engine room and the lower part of the passenger compartment of an automobile is the target of analysis, and the state and motion of various devices and the air present in the model space are simulated by the thermal fluid analysis software 3.

[0022] Evaluation Program 4 is a program that uses the functions of thermal fluid analysis software 3 to quantitatively evaluate the influence of thermal convection. Evaluation Program 4 has the function of quantifying the influence of thermal convection from multiple heat sources present in the model space to a single target component, and calculating how much each heat source is influencing the temperature change of the target component. In other words, Evaluation Program 4 has the function of numerically expressing how much each heat source contributes to the temperature rise of a single target component that is affected by thermal convection from multiple heat sources.

[0023] Output device 5 is a device that outputs the calculation results from evaluation device 2, and is, for example, a display or a printer. Input device 6 is a device for inputting information into evaluation device 2, and is, for example, a keyboard or a mouse. Evaluation device 2 may also be equipped with a communication device for exchanging information with other computers, or it may be possible to exchange information via a communication network such as the Internet or a local area network.

[0024] According to the thermal fluid analysis software 3 described above, it is possible to estimate how much the temperature of a target component in the model space will rise. However, when focusing on the cause of the temperature rise of that component, it is difficult to determine whether it is due to thermal radiation (electromagnetic waves), heat conduction (vibration), or thermal convection (fluid movement), and it is particularly difficult to grasp the degree of temperature rise due to thermal convection. Furthermore, when there are multiple heat sources, it is difficult to compare the magnitude of the influence of each heat source (contribution to the temperature rise), and it is particularly difficult to compare the influence ratio of thermal convection. Taking these challenges into account, the evaluation program 4 described above provides a method for quantifying the influence ratio of thermal convection from each heat source to a single target component.

[0025] [2. Model Space] Figure 2 illustrates the model space to be analyzed by the thermal fluid analysis software 3. This model space simulates the engine compartment and the space under the passenger compartment of an automobile. The overall shape of the model space is set based on three-dimensional shape data created, for example, with general-purpose three-dimensional CAD (Computer Aided Design) software. In this embodiment, the model space includes an engine 10, intake pipe 11, exhaust pipe 12, supercharger 13 (turbocharger), exhaust catalytic converter 14, transmission 15, heat exchanger 16 (radiator), joint 17, propeller shaft 18, etc.

[0026] In Figure 2, the engine 10 is positioned transversely. The intake manifold is fixed to the front of the engine 10, and the exhaust manifold is fixed to the rear of the engine 10. The supercharger 13 is positioned adjacent to the rear of the exhaust manifold. The exhaust pipe 12 is routed to pass through the turbine of the supercharger 13, and the intake pipe 11 is routed to pass through the compressor of the supercharger 13. Downstream of the supercharger 13, the exhaust pipe 12 extends vertically downwards before extending almost horizontally towards the rear of the vehicle.

[0027] The catalytic converter 14 is installed in the exhaust pipe 12 downstream of the supercharger 13. The catalytic converter 14 is interposed in the portion of the exhaust pipe 12 that extends vertically downstream of the supercharger 13. The transmission 15 is located adjacent to the left side of the engine 10. The driving force shifted by the transmission 15 is transmitted to the propeller shaft 18 via a joint 17 attached to the rear of the transmission 15. The propeller shaft 18 extends in the longitudinal direction of the vehicle and transmits the driving force supplied to the rear wheels.

[0028] The heat exchanger 16, which air-cools the engine coolant, is positioned in front of the engine 10 and the transmission 15. Cooling air that passes through the heat exchanger 16 in the engine compartment flows along the surfaces of the engine 10 and the transmission 15 towards the rear of the vehicle. Cooling air that passes between the engine 10 and the transmission 15 also flows along the surfaces of the exhaust pipe 12 and the propeller shaft 18 towards the rear of the vehicle.

[0029] In this embodiment, the engine 10, exhaust pipe 12, supercharger 13, catalytic converter 14, transmission 15, and heat exchanger 16 each function as a heat source. The components to be analyzed are, for example, power transmission system components such as the joint 17 and propeller shaft 18. The arrangement of the components to be analyzed in this embodiment (joint 17, propeller shaft 18) has the following characteristics. The part in question is located at the rear of the lower end of engine 10. The component in question is interposed between the transmission 15 and the exhaust pipe 12. The component in question is located near the rear end of the transmission 15 or behind the transmission 15. The component in question is located near the transmission 15 and below the supercharger 13. The target component is located near the exhaust pipe 12 through which the exhaust gas that has passed through the catalytic converter 14 flows. The component in question is located in a position where it is exposed to the cooling air that passes through the heat exchanger 16 and flows between the engine 10 and the transmission 15.

[0030] The target component preferably has the following characteristics. These characteristics contribute to improving the accuracy of the analysis and are preferable for accurately quantifying the influence of thermal convection. The target components are those that are not significantly affected by thermal radiation and thermal conduction. (It is located at a reasonable distance from the hot engine 10, supercharger 13, and catalytic converter 14.) • The surface temperature of the target component is less than or equal to the temperature of the surrounding air, or less than or equal to the temperature of the surrounding air plus a predetermined positive value. (The effects of thermal radiation and thermal conduction are estimated to be relatively small.) • The target components are those that are susceptible to the effects of thermal convection. (It is in the flow of high-temperature cooling air.)

[0031] [3. Evaluation Method] Figure 3 is a flowchart showing the evaluation method (control flow in evaluation program 4) of this embodiment. When an operator operating the evaluation device 2 gives an instruction to quantitatively evaluate the influence ratio of thermal convection, for example, evaluation program 4 uses the thermal fluid analysis software 3 to execute the process shown in Figure 3. Steps A6 and A7 of steps A1 to A7 are optional.

[0032] In step A1 (the first step), parameters related to the surface temperature of each heat source in the model space are estimated. Specific examples of these parameters include the following: • Average surface temperatures of each heat source T1, T2, ..., T n (Average surface temperature) [Units: K, °C] ·Average temperature T1,T2,…,T n and temperature T air The difference [units: K, °C] • Heat energy on the surface of each heat source [Unit: W] • Heat flux on the surface of each heat source [Unit: W / m] 2 ]

[0033] Average temperature T1,T2,…,T n This is, for example, the area-weighted average temperature at the interface (contact surface with the fluid) of each heat source. airIt may be the average temperature in the entire model space, or the average temperature of the air in contact with each heat source may be calculated for each heat source. Here, n is the serial number of natural numbers assigned to each heat source, indicating that n heat sources are provided.

[0034] The model space contains a plurality of heat sources, one target component, and other elements (various components and devices). The thermal fluid analysis software 3 sets an initial temperature for all elements existing in the model space. Also, the thermal fluid analysis software 3 assumes that there exists a fluid (air) forming a predetermined initial temperature field, initial velocity field (initial flow field), and initial pressure field in the model space. The thermal fluid analysis software 3 simulates the movement and distribution of the amount of heat released from each heat source in consideration of the fluctuations in the temperature field, velocity field, and pressure field of the fluid.

[0035] FIG. 4 is a diagram illustrating the temperature distribution of the model space analyzed by the thermal fluid analysis software 3. The evaluation program 4 estimates the average temperatures T1, T2,..., T n , heat quantity, and heat flux of the surfaces of each heat source based on such a temperature distribution. The air temperature T air is calculated based on the temperature of the fluid in the model space. Note that when estimating the average temperatures T1, T2,..., T n , heat quantity, and heat flux, the surface of one heat source may be divided into a plurality of regions, and the average temperature, average heat quantity, and average heat flux in each region may be calculated. That is, assuming that one device functioning as a heat source is composed of a plurality of heat source parts, the average temperature, average heat quantity, and average heat flux may be calculated for each heat source part.

[0036] The case where the above parameters are the differences (temperature differences) between the average temperatures T1, T2,..., T n and the air temperature T air will be described in detail. Here, let the difference between the average temperatures T1, T2,..., T n and the air temperature T air be defined as "reference temperatures T’1, T’2,..., T’ n ". The reference temperatures T’1, T’2,..., T’ nThis represents the magnitude of the ability of each heat source to exert a thermal convection effect on the fluid in the model space. Reference temperatures T'1, T'2, ..., T' n The formula for calculating it is shown below. T'1 = T1 - T air ,T'2=T2-T air ,… ,T' n =T n -T air

[0037] In step A2 (second step), a virtual substance with a concentration corresponding to the parameter is set on the surface of each heat source. This virtual substance is assumed to have no effect on the temperature, velocity, and pressure fields of the model space, and to be particles that passively move and diffuse along the fluid velocity field. The concentration of the virtual substance on the surface of each heat source is set to be higher as the parameter value increases.

[0038] The above parameters are reference temperatures T'1, T'2, ..., T' n If so, the reference temperatures T'1, T'2, ..., T' n The larger the value of the parameter (i.e., the greater the temperature difference), the higher the concentration of the virtual substance will be set. The same applies when the parameters are heat flux and heat quantity; the larger the heat flux and heat quantity, the higher the concentration of the virtual substance will be set. Therefore, the larger the value of the parameter, the higher the possibility that the virtual substance will diffuse over a wide area and over a long distance. The concentration of the virtual substance is called a passive scalar because it is a scalar that changes passively in the model space.

[0039] The degree of diffusion of a virtual substance depends on its diffusion coefficient. A smaller diffusion coefficient makes the virtual substance more susceptible to the influence of a velocity field (e.g., cooling air flow) and less susceptible to the influence of a temperature field (e.g., convection due to temperature difference). Conversely, a larger diffusion coefficient makes the virtual substance less susceptible to the influence of a velocity field and more susceptible to the influence of a temperature field. The specific value of the diffusion coefficient is set appropriately according to the desired properties of the virtual substance. The diffusion coefficient of the virtual substance may be set to be greater than, for example, the diffusion coefficient of air, the same as, or less than the diffusion coefficient of air. Preferably, the diffusion coefficient of the virtual substance is set to be the same as the diffusion coefficient of air. By giving the virtual substance such a temperature dependence, the validity of the evaluation of the influence ratio is improved.

[0040] In step A3 (third step), a simulation is performed using thermal fluid analysis software 3 to simulate the diffusion and convection of virtual material from the surface of each heat source (i.e., moving along the velocity field while diffusing), with at least two parameters, the temperature field and the velocity field, fixed in the model space. The pressure field in the model space may also be fixed. In this simulation, since the virtual material does not affect the temperature field, velocity field, or pressure field of the fluid, the computational load is reduced, and the simulation can be completed in a short time.

[0041] In step A4 (fourth step), the concentrations of the virtual substance that have reached the surface of the target part are called the reached concentrations P1, P2, ..., P n The concentrations are estimated for each heat source. Heat sources with a strong influence of thermal convection on the target component are thought to cause a large amount of virtual material to reach the surface of the component. Therefore, the resulting concentrations P1, P2, ..., P n The higher the value, the stronger the influence of thermal convection on the target component is estimated to be from the heat source that gives rise to the virtual substance.

[0042] In step A5 (the fifth step), the concentrations P1, P2, ..., P from each heat source are determined. n The ratio of these is the proportion of influence of thermal convection, R1, R2, ..., R nIt is calculated as follows: Influence ratios R1, R2, ..., R n This represents the degree of influence of thermal convection exerted by each heat source on the target component. Influence ratios R1, R2, ..., R n The calculation formula is shown below. A is the target concentration P1, P2, ..., P n It is the sum of [the numbers]. A = P1 + P2 + ... + P n R1=P1 / A, R2=P2 / A, ..., R n =P n / A

[0043] In step A6 (sixth step), the influence ratios of thermal convection are R1, R2, ..., R n The output is sent to output device 5. The black bar graph in Figure 5 shows the quantified influence ratios of thermal convection R1, R2, ..., R n This graph illustrates the following: The influence ratio R of the heat exchanger 16 is the highest, while the influence ratio R of the engine 10, supercharger 13, catalytic converter 14, etc., which are at relatively high temperatures, is relatively low. Therefore, focusing on the influence of thermal convection, it is clear that the position of the heat exchanger 16 and the flow of cooling air need to be considered more than the engine 10, supercharger 13, catalytic converter 14, and transmission 15.

[0044] Furthermore, the white bar graph in Figure 5 represents the influence ratios R1, R2, ..., R n These are reference values ​​derived from test simulations to verify the reliability of the values. In the test simulations, a uniform temperature was applied to only one heat source, and the velocity field in the model space was fixed to the initial velocity field. The temperature rise of the target component was calculated by simulating the general fluid behavior that affects the temperature field, velocity field, and pressure field in the model space. This temperature rise was calculated for each heat source, and the ratio was used as a reference value corresponding to the length of the white bar graph. According to the inventors' verification, the correlation coefficient between the length of the black bar graph and the length of the white bar graph is 0.88, and the above influence ratios R1, R2, ..., R n It was confirmed that it has sufficiently effective accuracy.

[0045] In step A7 (seventh step), based on the concentration distribution of the virtual substance in the model space, isosurfaces 20 of a predetermined concentration are output as a three-dimensional image to the output device 5. Figure 6 shows an example of isosurfaces 20 where the concentration of the virtual substance diffused and convected from the surface of the supercharger 13 is the same. By using such a three-dimensional image, it becomes easier to visually grasp the range of influence of thermal convection caused by the heat source and the tendency of its spread (direction of heat transfer due to thermal convection).

[0046] In the example shown in Figure 6, it can be seen that the area of ​​influence of thermal convection from the supercharger 13 tends to flow towards the rear of the vehicle along with the flow of cooling air, making it difficult for it to reach the target components, the joint 17 and the propeller shaft 18. This is thought to explain one reason why the influence ratio R of the supercharger 13 is lower than the influence ratio R of the heat exchanger 16 when comparing the high-temperature supercharger 13 with the low-temperature heat exchanger 16.

[0047] [4. Effects] (1) The above evaluation method and evaluation program are for quantitatively evaluating the influence ratio of thermal convection from multiple heat sources to a single target component using thermal fluid analysis software 3. The above evaluation device 2 also quantitatively evaluates the influence ratio of thermal convection from multiple heat sources to a single target component using thermal fluid analysis software 3.

[0048] The evaluation method described above comprises, for example, step A1 (first step), step A2 (second step), step A3 (third step), step A4 (fourth step), and step A5 (fifth step), as shown in Figure 3. The evaluation program described above causes the evaluation device 2 (computer) to execute steps A1 to A5. The evaluation device 2 executes the processes corresponding to steps A1 to A5.

[0049] Step A1 is the process of estimating parameters related to the surface temperature of each heat source in a model space that includes multiple heat sources and target parts. Here, for example, reference temperatures T'1, T'2, ..., T' nThe values ​​of heat flux and heat quantity can be determined. Step A2 is the process of setting up a virtual substance with a concentration corresponding to the parameter on the surface of each heat source.

[0050] Step A3 is the process of fixing the velocity and temperature fields in the model space and performing a simulation in which a virtual substance diffuses and convects from the surface of each heat source. Step A4 is the process of determining the reached concentrations P1, P2, ..., P, which are the concentrations of the virtual substance that reach the surface of the target part. n Step A5 is the process of estimating the concentrations P1, P2, ..., P from each heat source. n The ratio of these is the influence ratio of thermal convection, R1, R2, ..., R n This is the process of calculating it as follows.

[0051] The above configuration allows for accurate determination of the influence of thermal convection from multiple heat sources on a single target component (which heat source has the greatest influence on the target component through thermal convection). This enables, for example, determining the most influential components R1, R2, ..., R n By reducing the heat output of a large heat source, or by placing a heat shield between the heat source and the target component, the temperature rise of the target component can be efficiently suppressed. Furthermore, the influence ratios R1, R2, ..., R n Because this can be understood quantitatively, it is possible to improve the accuracy of estimations, for example, of how much temperature reduction can be expected in a target component when the effect of thermal convection from a specific heat source is reduced.

[0052] (2) The above evaluation method is the influence ratio of thermal convection for each heat source R1, R2, ..., R n The system includes step A6 (sixth step) which outputs to output device 5. The influence ratios of thermal convection for each heat source are R1, R2, ..., R n This can be displayed, for example, as a bar graph as shown in Figure 5. This configuration makes it easy to compare the influence of each heat source on thermal convection. Therefore, the effect of thermal convection from multiple heat sources on a single target component can be accurately understood.

[0053] (3) The above evaluation method includes step A7 (seventh step), which outputs isosurfaces of a predetermined concentration as a three-dimensional image to the output device 5 based on the concentration distribution of the virtual substance in the model space. This three-dimensional image can be displayed superimposed on the three-dimensional image of the model space, for example, as shown in Figure 6. With this configuration, the influence range of each heat source related to thermal convection and the direction of heat transfer due to thermal convection can be displayed in an easy-to-understand visual manner. Furthermore, it is possible to display not only the isosurfaces of the virtual substance diffused from one heat source, but also the isosurfaces of the virtual substance diffused from multiple heat sources simultaneously. Therefore, the influence of thermal convection from multiple heat sources on a single target component can be grasped with high accuracy.

[0054] (4) In the above evaluation method, it is preferable that the target component has a surface temperature that is at least the same as or less than the temperature of the adjacent air (or less than or less than the temperature of the adjacent air plus a predetermined positive value). This configuration is useful for confirming that the effects of thermal radiation and thermal conduction on the target component are relatively small. That is, by confirming that the target component is relatively susceptible to the effects of thermal convection and then performing the above evaluation method, the quantified influence ratios R1, R2, ..., R n The reliability of the value can be improved.

[0055] (5) In the above evaluation method, it is preferable that the heat source includes two or more of the engine 10, supercharger 13, catalytic converter 14, transmission 15, and heat exchanger 16 mounted on the automobile. The engine 10 and its auxiliary devices mounted on the automobile are often located in close proximity within the engine compartment, making it difficult to accurately grasp the magnitude of the thermal influence on surrounding parts. On the other hand, by performing the above evaluation method, the influence ratios R1, R2, ..., R from multiple heat sources to a single target part can be determined. n This allows for a quantitative understanding of the effect of heat convection from multiple heat sources to a single target component, enabling a highly accurate assessment.

[0056] (6) In the above evaluation method, the target component is preferably a power transmission system component mounted on an automobile. Power transmission system components mounted on an automobile are often located near the engine 10 and the transmission 15, making it difficult to accurately grasp the magnitude of the thermal influence from surrounding heat sources. On the other hand, by performing the above evaluation method, the influence ratios of thermal convection from multiple heat sources to a single target component R1, R2, ..., R n This allows for a quantitative understanding of the effect of heat convection from multiple heat sources to a single target component, enabling a highly accurate assessment.

[0057] [5. Others] The above embodiments are merely illustrative examples, and there is no intention to exclude various modifications or applications of techniques not explicitly stated in these embodiments. Each configuration of these embodiments can be modified in various ways without departing from their intended purpose. Furthermore, each configuration of these embodiments can be selected or combined as needed.

[0058] Steps A6 and A7 shown in Figure 3 are optional. In this case, the influence ratios of thermal convection R1, R2, ..., R calculated in step A5 are omitted. n The information of the heat source corresponding to the highest influence ratio R may be displayed on the output device 5, or the influence ratios R1, R2, ..., R may be transmitted to other computers via the network. n The information may also be transmitted. The essence of this invention lies in quantitatively evaluating the influence ratio of thermal convection. The specific methods for utilizing and presenting the quantitatively evaluated influence ratio can be arbitrarily selected. [Industrial applicability]

[0059] This technology is applicable to manufacturing industries where the arrangement and performance of heat sources and target components are designed based on the influence ratio of thermal convection from multiple heat sources to a single target component. For example, it is applicable to the automotive, shipbuilding, aerospace, and energy industries. It is also applicable to service industries that quantitatively evaluate the influence ratio of thermal convection from multiple heat sources to a single target component. [Explanation of Symbols]

[0060] 1. Evaluation System 2. Evaluation device (computer) 3. Thermal Fluid Analysis Software 4. Evaluation Program 5. Output device 6 Input devices 10 Engines 11 Intake pipe 12 Exhaust pipes 13 Supercharger 14. Catalytic converter 15. Transmission 16 Heat exchanger 17 Joints 18 Propeller Shafts 20 Isosurface

Claims

1. An evaluation method for quantitatively evaluating the influence ratio of thermal convection from multiple heat sources to a single target component using thermal fluid analysis software, In a model space including the plurality of heat sources and the target component, the first step is to estimate parameters related to the surface temperature of each of the heat sources, A second step involves setting a virtual substance having a concentration corresponding to the parameter on the surface of each of the heat sources, A third step involves fixing the velocity field and temperature field in the model space and performing a simulation in which the virtual material undergoes diffusion and convection from the surface of each of the heat sources, A fourth step involves estimating the attained concentration, which is the concentration of the virtual substance that has reached the surface of the target component, for each heat source. A fifth step in which the ratio of the concentrations obtained from each of the heat sources is calculated as the influence ratio. An evaluation method characterized by comprising the following features.

2. The aforementioned parameter is a reference temperature calculated as the difference between the average temperature on the surface of each heat source and the ambient temperature. The evaluation method according to claim 1, characterized in that

3. The parameter is the amount of heat at the surface of each of the heat sources. The evaluation method according to claim 1, characterized in that

4. The parameter is the heat flux at the surface of each of the heat sources. The evaluation method according to claim 1, characterized in that

5. The sixth step includes outputting the influence ratio for each heat source to an output device. The evaluation method according to claim 1, characterized in that

6. The seventh step involves outputting an isosurface of a predetermined concentration as a three-dimensional image to an output device, based on the concentration distribution of the virtual substance in the model space. The evaluation method according to claim 1, characterized in that

7. The aforementioned component has a surface temperature that is at least the same as or lower than the temperature of the surrounding air. The evaluation method according to claim 1, characterized in that

8. The heat source includes two or more of the following components installed in an automobile: an engine, a supercharger, a catalytic converter, a transmission, and a heat exchanger. The evaluation method according to claim 1, characterized in that

9. The aforementioned component is a power transmission system component installed in an automobile. The evaluation method according to claim 1, characterized in that

10. An evaluation program for quantitatively evaluating the influence ratio of thermal convection from multiple heat sources to a single target component using thermal fluid analysis software, In a model space including the plurality of heat sources and the target component, the first step is to estimate parameters related to the surface temperature of each of the heat sources, A second step involves setting a virtual substance having a concentration corresponding to the parameter on the surface of each of the heat sources, A third step involves fixing the velocity field and temperature field in the model space and performing a simulation in which the virtual material undergoes diffusion and convection from the surface of each of the heat sources, A fourth step involves estimating the attained concentration, which is the concentration of the virtual substance that has reached the surface of the target component, for each heat source. A fifth step in which the ratio of the concentrations obtained from each of the heat sources is calculated as the influence ratio. An evaluation program characterized by causing a computer to execute it.

11. An evaluation device that uses thermal fluid analysis software to quantitatively evaluate the influence ratio of thermal convection from multiple heat sources to a single target component, In the model space including the multiple heat sources and the target component, parameters related to the surface temperature of each heat source are estimated. On the surface of each of the heat sources, a virtual substance having a concentration corresponding to the parameter is set, A simulation is performed in which the velocity field and temperature field in the aforementioned model space are fixed, and the virtual material is subjected to diffusion and convection from the surface of each of the heat sources. The concentration of the virtual substance that has reached the surface of the target component is estimated for each heat source. The ratio of the concentrations obtained from each of the heat sources is calculated as the influence ratio. An evaluation device characterized by the following features.

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