Thermal fluid analysis method
By classifying thermal fluid analysis targets into divided units based on heat transfer processes and generating functional modules for numerical calculations, the method addresses the inefficiencies of existing thermal fluid analysis methods, achieving reduced calculation targets and shorter analysis times.
Patent Information
- Application Number
- JP2023206940
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-12-07
- Publication Date
- 2025-06-19
AI Technical Summary
The existing thermal fluid analysis methods using CFD require a large number of meshes, leading to increased analysis load and time, which prolongs the thermal design and development process of thermal fluid devices.
The proposed method classifies the analysis target into divided units based on the heat transfer process, generating an analysis model composed of functional modules, and performs numerical calculations on this model to reduce the number of numerical calculation targets and shorten analysis time.
This approach significantly reduces the number of numerical calculation targets and shortens the analysis time, thereby accelerating the thermal design and development process of thermal fluid devices.
Smart Images
Figure 2025091606000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a method for thermal fluid analysis.
Background Art
[0002] Non-Patent Document 1 below discloses the application of a thermal fluid resistance network method to fluid analysis in a thin housing for the purpose of constructing a forced convection heat design scheme and identifying problems for ensuring high accuracy by using a thermal fluid resistance network method that combines a fluid resistance network method and a thermal circuit network method. In this background art, a thermal analysis of a thin housing based on the thermal fluid resistance network method is performed by using a CFD (Computational Fluid Dynamics) code for heat design, and based on the results of this thermal analysis, a forced convection heat design scheme is constructed and problems for ensuring high accuracy are identified.
Prior Art Documents
Non-Patent Documents
[0003]
Non-Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] By the way, in the above CFD, a mesh model in which a thermal fluid device such as a thin housing is divided into a large number of meshes is created on a computer, and the analytical results of the thermal fluid to be analyzed are obtained by solving the model equations set for each mesh with a computer. However, the number of meshes that are the target of numerical calculation is directly related to the analysis load of the thermal fluid device.
[0005] That is, as the number of meshes increases, the analysis load on the thermal fluid device increases, and as a result, the analysis time by the computer increases. Such an increase in the analysis time lengthens the time required for the thermal design of the thermal fluid device, and consequently becomes a factor in lengthening the development period of the thermal fluid device.
[0006] The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a thermal fluid analysis method capable of reducing the number of numerical calculation targets compared to the prior art and shortening the analysis time.
Means for Solving the Problem
[0007] In order to achieve the above object, in the present invention, as a first solution means for the thermal fluid analysis method, an analysis target classification step of classifying an analysis target into a plurality of divided units based on a heat transfer process, and applying a predetermined thermal fluid analysis method to the plurality of divided units, thereby generating an analysis model composed of a plurality of functional modules, and an analysis step of obtaining a thermal fluid analysis result by performing numerical calculation processing on the analysis model.
[0008] In the present invention, as a second solution means for the thermal fluid analysis method, in the above first solution means, the analysis target is a heat exchanger having a flat overall shape.
[0009] In the present invention, as a third solution means for the thermal fluid analysis method, in the above second solution means, the functional module is generated by vertically and horizontally dividing the heat exchanger.
[0010] In the present invention, as a fourth solution means for the thermal fluid analysis method, in the above second or third solution means, the heat exchanger includes a heat medium inlet and a heat medium outlet arranged apart from each other, a plurality of measurement points are set between the heat medium inlet and the heat medium outlet, and the validity of the thermal fluid analysis result is evaluated based on a comparison with the temperature measurement result at the measurement point.
[0011] In the present invention, as a fifth solution means related to the thermal fluid analysis method, in the above fourth solution means, the means of adopting the thermal fluid analysis method as the thermal fluid resistance network method is employed.
Advantages of the Invention
[0012] According to the present invention, it is possible to provide a thermal fluid analysis method capable of reducing the number of numerical calculation targets compared with the prior art and realizing shortening of the analysis time.
Brief Description of the Drawings
[0013]
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Modes for Carrying Out the Invention
[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, the analysis target in the present embodiment will be described with reference to FIG. 1. The analysis target in the present embodiment is the cooling jacket A and the plurality of heaters B shown in FIG. 1.
[0015] The cooling jacket A is a heat exchanger with a flat overall shape as shown in the figure, and it is a type of heat fluid device. The cooling jacket A includes a main body portion 1, an inflow portion 2, and an outflow portion 3. The main body portion 1 is a flat and rectangular plate portion, and a flow path through which a heat medium (working fluid) flows is formed inside. This flow path is a space surrounded by an upper plate 1a, a lower plate 1b, a right side wall 1c, and a left side wall 1d, and a plurality of heat transfer fins 1e are provided at predetermined intervals.
[0016] That is, the main body portion 1 is formed by the upper plate 1a, the lower plate 1b, the right side wall 1c, the left side wall 1d, and a plurality of heat transfer fins 1e, and includes a plurality of strip-shaped flow paths adjacent to each other in a parallel state. In such a plurality of strip-shaped flow paths, the heat medium (working fluid) flows from the inflow portion 2 toward the outflow portion 3.
[0017] The inflow portion 2 is adjacently arranged on one end side (upstream side) in the extending direction of the plurality of strip-shaped flow paths in the main body portion 1 so as to communicate with the main body portion 1. The internal space (inlet space) of the inflow portion 2 communicates with one end of the plurality of strip-shaped flow paths, and a heat medium inlet 2a is formed. Such an inflow portion 2 supplies the heat medium (working fluid) supplied from the outside through the heat medium inlet 2a to the inlet space to the plurality of strip-shaped flow paths in the main body portion 1.
[0018] The outflow portion 3 is adjacently arranged on the other end side (downstream side) in the extending direction of the plurality of strip-shaped flow paths in the main body portion 1 so as to communicate with the main body portion 1. The internal space (outlet space) of the outflow portion 3 communicates with the other end of the plurality of strip-shaped flow paths, and a heat medium outlet 3a is formed. Such an outflow portion 3 discharges the heat medium (working fluid) supplied from the plurality of strip-shaped flow paths in the main body portion 1 to the outlet space to the outside through the heat medium outlet 3a.
[0019] In FIG. 1, reference numeral B denotes a plurality of heaters that simulate the object to be cooled by the cooling jacket A in this embodiment. In FIG. 4, for the sake of convenience, the plurality of heaters B are depicted as being separated from the lower plate 1b, but the plurality of heaters B are orthogonally arranged like a checkerboard on the surface of the lower plate 1b in the main body portion 1.
[0020] The plurality of heaters B are each formed in a rectangular shape as shown in the figure, and are orthogonally arranged so that two opposite sides (long sides) are parallel to two opposite sides (long sides) of the upper plate 1a and the lower plate 1b of the main body 1. Such a plurality of heaters B are the heat sources in the cooling jacket A, that is, the objects to be cooled. The thermal fluid analysis method according to the present embodiment analyzes such a cooling jacket A and a plurality of heaters B.
[0021] In the design of such a cooling jacket A, the heat exchange performance between the cooling jacket A and the plurality of heaters B (objects to be cooled) is a major consideration. The thermal fluid analysis method according to the present embodiment is for evaluating the heat exchange performance between the cooling jacket A and the plurality of heaters B. In the thermal fluid analysis method according to the present embodiment, in order to evaluate its validity, a plurality of measurement points are set on the cooling jacket A, and the validity is evaluated based on the comparison between the analysis result and the temperature measurement result of each measurement point.
[0022] The plurality of measurement points described above are set between the heat medium inlet 2a and the heat medium outlet 3a as optimal points for evaluating the heat exchange performance between the cooling jacket A and the plurality of heaters B. Such a plurality of measurement points are set at five points at predetermined intervals on the central strip-shaped flow path (central strip-shaped flow path) among the plurality of strip-shaped flow paths in the main body 1, as shown as measurement points P1 to P5 in FIG. 2.
[0023] The thermal fluid analysis method according to the present embodiment uses a computer equipped with a predetermined analysis program to perform various arithmetic processes on the data related to the above-described analysis objects (cooling jacket A and plurality of heaters B) to generate a divided model M1 and an analysis model M2, and performs numerical calculation processing on the analysis model M2 to obtain a thermal fluid analysis result (simulation result).
[0024] In this thermal fluid analysis method, a divided model M1 is first generated by using data related to the analysis target (cooling jacket A and a plurality of heaters B). As shown in FIG. 1, this divided model M1 is composed of a plurality of divided units s11 to s55 obtained by orthogonally dividing the main body 1 into a grid pattern, an inflow section 2, and an outflow section 3.
[0025] The plurality of divided units s11 to s55 are obtained by dividing the main body 1 into a total of 25 units corresponding to 25 heaters B. Since each of these divided units s11 to s55 corresponds to a plurality of heaters B, it can be considered that they are parts where the heat transfer process is the same or similar in the main body 1.
[0026] That is, in the thermal fluid analysis method according to the present embodiment, the analysis target is divided into a plurality of divided units s11 to s55 based on the heat transfer process. The process of setting the divided model M1 composed of such a plurality of divided units s11 to s55 corresponds to the analysis target division step in the present invention.
[0027] Here, the above-described measurement points P1 to P5 are located on five divided units s13, s12, S33, s43, s53 located at the center in the direction (left - right direction) orthogonal to the extending direction of the five strip - shaped flow paths L1 to L5 in the divided model M1. That is, the first measurement point P1 is located on the third strip - shaped flow path L3 and at the center of the divided unit s13.
[0028] The second measurement point P2 is also located on the third strip - shaped flow path L3 and at the center of the divided unit s23. The third measurement point P3 is located on the third strip - shaped flow path L3 and at the center of the divided unit s33. The fourth measurement point P4 is located on the third strip - shaped flow path L3 and at the center of the divided unit s43. The fifth measurement point P5 is located on the third strip - shaped flow path L3 and at the center of the divided unit s53.
[0029] Next, in the thermal fluid analysis method according to the present embodiment, as shown in FIG. 1, an analysis model M2 composed of a plurality of functional modules FM11 to FM55 is generated based on the divided model M1. This analysis model M2 is numerically modeled by applying a predetermined thermal fluid analysis method to a plurality of divided units s11 to s55 in the divided model M1.
[0030] As the thermal fluid analysis method in the present embodiment, for example, the thermal fluid resistance network method described in Non-Patent Document 1 is adopted. That is, the plurality of functional modules FM11 to FM55 are numerically modeled based on the thermal fluid resistance network method in which a well-known thermal circuit network method and a fluid resistance network method are connected in series.
[0031] Since such a plurality of functional modules FM11 to FM55 are based on a plurality of divided units s11 to s55 provided corresponding to the plurality of heaters B, the heat transfer processes are the same or similar. The generation process of the analysis model M2 composed of the plurality of functional modules FM11 to FM55 corresponds to the analysis model generation step of the present invention.
[0032] Here, FIG. 3 is a schematic diagram showing the heat conduction of the analysis target (cooling jacket A and a plurality of heaters B) in the present embodiment. As shown in these FIG. 3, the heat generated by the plurality of heaters B, which are heat sources, is transferred to the lower plate 1b, and diffusion due to heat conduction occurs in the lower plate 1b. That is, the lower plate 1b is heated substantially evenly by the plurality of heaters B. Note that a part of the heat generated by the plurality of heaters B (heat sources) dissipates to the surroundings by natural convection or radiation.
[0033] The heat transferred from the plurality of heaters B (heat sources) to the lower plate 1b is transferred to the plurality of heat transfer fins 1e in the main body 1. Then, the plurality of heat transfer fins 1e transfer a part of the heat to the heat medium (working fluid) by heat exchange with the heat medium (working fluid) flowing through the five strip-shaped flow paths L1 to L5.
[0034] Heat conduction as shown in Fig. 4 occurs between the plurality of heat transfer fins 1e and the heat medium (working fluid) flowing through the five strip-shaped flow paths L1 to L5. That is, when focusing on one strip-shaped flow path, the heat medium (working fluid) flowing through the strip-shaped flow path is heated by heat transfer from the left and right heat transfer fins forming the strip-shaped flow path.
[0035] Also, among the heat transferred from the plurality of heaters B (heat sources) to the lower plate 1b, the rest is transferred from the plurality of heat transfer fins 1e to the upper plate 1a. In the upper plate 1a, diffusion due to heat conduction occurs, and the upper plate 1a is heated substantially evenly by the heat transferred from the plurality of heat transfer fins 1e. Then, the heat transferred to the upper plate 1a dissipates to the surroundings by natural convection and radiation.
[0036] Here, when applying the conventional thermal fluid analysis method based on CFD to the analysis targets (cooling jacket A and plurality of heaters B) in this embodiment, a mesh model in which the cooling jacket A and the plurality of heaters B are divided into a large number of meshes is created on a computer, and the model equations set for each mesh are solved by the computer.
[0037] In contrast, in this embodiment, a plurality of divided units s11 to s55 are set on a computer for each of the plurality of heaters B for which the heat transfer process can be considered to be the same, and by numerically modeling each of the divided units s11 to s55, a plurality of functional modules FM11 to FM55 corresponding to each heater B are generated on the computer.
[0038] Subsequently, in the thermal fluid analysis method according to this embodiment, a thermal fluid analysis result (simulation result) is obtained by performing numerical calculation processing on the analysis model M2 generated in this way. The numerical calculation processing for this analysis model M2 corresponds to the analysis step of the present invention.
[0039] FIG. 5 is a characteristic diagram showing the effectiveness of the thermal fluid analysis method according to the present embodiment. Among the two characteristic diagrams shown in FIG. 5, the characteristic diagram of FIG. 5(a) compares the temperature rise in the third strip-shaped flow path L3 with the analysis result of the thermal fluid analysis method according to the present embodiment and the measurement results at five measurement points P1 to P5.
[0040] In the characteristic diagram of FIG. 5(a), the horizontal axis is a value obtained by normalizing the distance from the heat medium inlet 2a. The analysis result and the measurement result were 9.6% when Red = 230 and 6.0% when Red = 310. The analysis result and the measurement result are in good agreement, sufficiently showing the effectiveness of the thermal fluid analysis method according to the present embodiment.
[0041] Also, the characteristic diagram of FIG. 5(b) compares the heat medium temperature (working fluid temperature) at the heat medium outlet 3a based on the analysis result of the thermal fluid analysis method according to the present embodiment with the measurement result of the heat medium temperature (working fluid temperature) at the heat medium outlet 3a. As shown in the characteristic diagram of FIG. 5(b), the heat medium temperature (working fluid temperature) at the heat medium outlet 3a is in good agreement with the analysis result and the measurement result of the thermal fluid analysis method according to the present embodiment.
[0042] In such a thermal fluid analysis method according to the present embodiment, a divided model M1 is generated by dividing the analysis target (cooling jacket A and a plurality of heaters B) for each part where the heat transfer process can be considered to be the same in the analysis target (cooling jacket A and a plurality of heaters B).
[0043] Then, in the thermal fluid analysis method according to the present embodiment, a plurality of functional modules FM11 to FM55 are generated based on this divided model M1, thereby simulating the heat exchange performance of the analysis target (cooling jacket A and a plurality of heaters B). According to such a present embodiment, it is possible to provide a thermal fluid analysis method capable of reducing the number of numerical calculation targets compared to the prior art and shortening the analysis time.
[0044] Further, according to the present embodiment, it is possible to provide a thermal fluid analysis method capable of reducing the number of numerical calculation targets compared to the conventional method and shortening the analysis time for a cooling jacket A which is a heat exchanger having a flat overall shape.
[0045] Further, according to the present embodiment, by using a plurality of functional modules FM11 to FM55 generated by vertically and horizontally dividing the cooling jacket A (heat exchanger) into orthogonal parts, it is possible to provide a thermal fluid analysis method capable of reducing the number of numerical calculation targets compared to the conventional method and shortening the analysis time.
[0046] Furthermore, according to the present embodiment, the cooling jacket A (heat exchanger) includes a heat medium inlet 2a and a heat medium outlet 3a which are spaced apart, and a plurality of measurement points P1 to P5 are set between the heat medium inlet 2a and the heat medium outlet 3a. Since the validity of the thermal fluid analysis method according to the present embodiment is evaluated based on the comparison between the thermal fluid analysis results and the temperature measurement results at the plurality of measurement points P1 to P5, the effectiveness of the thermal fluid analysis method according to the present embodiment can be accurately evaluated.
[0047] Note that the present invention is not limited to the above embodiment, and for example, the following modification examples can be considered. (1) In the above embodiment, the cooling jacket A and the plurality of heaters B are used as the thermal fluid devices (analysis targets), but the present invention is not limited to this. The present invention can be applied to various thermal fluid devices other than the cooling jacket A and the plurality of heaters B.
[0048] (2) In the above embodiment, the cooling jacket A having a flat overall shape is used as the heat exchanger as the thermal fluid device, but the present invention is not limited to this. That is, the heat exchanger in the present invention is not limited to the cooling jacket A.
[0049] (3) In the above embodiment, the thermal fluid resistance network method is adopted as the thermal fluid analysis method, but the present invention is not limited to this. As the predetermined thermal fluid analysis method in the present invention, a method other than the thermal fluid resistance network method in which the thermal circuit network method and the fluid resistance network method are connected in series may be adopted.
Description of Symbols
[0050] A Cooling Jacket M1 Segmentation Model M2 Analysis Model FM11 to FM55 Functional Modules B Heater (Heat Source) 1 Main Body 1a Upper Plate 1b Lower Plate 1c Right Wall 1d Left Wall 1e Heat Transfer Fin 2 Inflow Section 2a Heat Medium Inlet 3 Outflow Section 3a Heat Medium Outlet
Claims
1. An analysis target classification step of classifying an analysis target into a plurality of divided units based on a heat transfer process, An analysis model generation step of generating an analysis model composed of a plurality of functional modules by applying a predetermined heat fluid analysis method to the plurality of divided units, An analysis step of obtaining a heat fluid analysis result by performing numerical calculation processing on the analysis model A heat fluid analysis method characterized by comprising the above.
2. The heat fluid analysis method according to claim 1, wherein the analysis target is a heat exchanger having a flat overall shape.
3. The heat fluid analysis method according to claim 2, wherein the functional module is generated by vertically and horizontally dividing the heat exchanger.
4. The heat exchanger includes a heat medium inlet and a heat medium outlet arranged apart from each other, A plurality of measurement points are set between the heat medium inlet and the heat medium outlet, The heat fluid analysis result is evaluated for validity based on comparison with the temperature measurement results at the measurement points, according to the heat fluid analysis method of claim 2 or 3.
5. The heat fluid analysis method according to claim 1 or 2, wherein the heat fluid analysis method is a heat fluid resistance network method.