JP6354320B2 - Temperature prediction method and temperature prediction device for parts - Google Patents

Description

  The present invention relates to a method and apparatus for predicting the temperature of a part present in a fluid region.

  Conventionally, in the design and development stage of industrial products, the temperature of parts constituting a finished product is predicted using computer simulation. For example, in Patent Document 1, the temperature distribution of an exhaust pipe is analyzed using an exhaust system model that includes an exhaust pipe through which exhaust flows and a heat shield disposed around the exhaust pipe with a space therebetween. A method is disclosed. In this method, a predetermined calculation grid is set in the exhaust system model, a predetermined boundary condition is given, and steady analysis is performed, thereby calculating the temperature distribution of the exhaust pipe at a certain point in time. As described above, by estimating the temperature distribution of a part at the drawing stage, it is possible to perform design in consideration of the temperature of the part, and optimization of product dimensions, layout, material characteristics, and the like is facilitated.

Japanese Patent No. 5397634

  However, since the technique of the above-mentioned Patent Document 1 performs calculations based on the steady analysis method, only the stable temperature during steady running can be predicted, and it cannot be applied to the temperature prediction of parts that cause unsteady phenomena. Here, the case where the key-off (engine stop) is performed from the steady running state in which the component temperature is stable due to the balance between the radiant heat input from the exhaust system and the convection heat radiation to the running wind will be considered. The amount of heat input from the exhaust system does not change greatly before and after key-off, and slowly decreases. On the other hand, the convective heat radiation amount decreases sharply when the traveling wind disappears. Therefore, the component temperature is expected to decrease after being temporarily increased. Since such a temperature change is a non-stationary phenomenon, a non-stationary analysis is required to predict it.

  As a method of unsteady analysis, there is a method in which all convection, heat conduction, and radiation are solved in a strong coupled analysis of a solid fluid, and a temperature change of the component is calculated. However, even if the prediction accuracy of the component temperature can be improved, a huge amount of calculation resources and calculation time are required, which makes it difficult to apply to product development. On the other hand, it is also conceivable to predict the component temperature by unsteady analysis using a weakly coupled method in which convection, heat conduction, and radiation are calculated separately. However, the calculation of the amount of heat transfer by convection does not take into account the exact temperature distribution and heat transfer direction of the wall surface, so it is difficult to increase the prediction accuracy of the component temperature even though the calculation time can be shortened. Such a problem is not limited to the exhaust system parts of the vehicle, and a similar problem may occur when predicting the temperature of a part existing in a fluid region such as air.

  One of the objects of the present case was created in view of the above-described problems, and is to provide a method and an apparatus that can predict the temperature of a component with high accuracy while reducing the calculation time. The present invention is not limited to this purpose, and is a function and effect derived from each configuration shown in the embodiments for carrying out the invention described later, and other effects of the present invention are to obtain a function and effect that cannot be obtained by conventional techniques. Can be positioned.

(1) The method for predicting the temperature of a component disclosed herein includes: a solid model obtained by modeling a part existing in a fluid region by dividing a contact portion of the part with the fluid into a plurality of cells; In this method, a fluid model obtained by dividing a contact portion with the component into a plurality of cells is set, and the temperature of the component is predicted by using thermal fluid analysis software.
The temperature prediction method includes, for each cell of the fluid model, a steady analysis step of calculating a fluid temperature of each cell and a wall surface temperature of each cell of the solid model adjacent to each cell by steady analysis; Based on the fluid temperature and the wall surface temperature at a plurality of time points calculated in the analysis step, a map creating step for creating a map in which the fluid temperature is expressed as a function of the wall surface temperature, and for each cell of the solid model, Calculating a heat transfer amount by unsteady analysis using the map created in the map creation step, and calculating a temperature based on the heat transfer amount, and in the map creation step, the fluid temperature The map is prepared that is approximated as a linear function of the wall surface temperature and provided with a limiting function that limits the extrapolated value of the fluid temperature.

(2) In the map creation step, it is preferable to divide a time region in which the function is calculated for each cell of the solid model every time the heat transfer direction changes .
( 3 ) It is preferable that the limiting function has the same sign as the slope of the linear function.

( 4 ) In the temperature prediction method, for each cell of the fluid model, the fluid temperature of each cell and the wall surface temperature of each cell of the solid model adjacent to each cell by a steady analysis using a predetermined boundary condition And calculating an initial map showing the relationship between the fluid temperature and the wall surface temperature, and using the initial map created in the initial map creation step for each cell of the solid model. It is preferable to include a boundary temperature calculation step of calculating a heat transfer amount by steady analysis and calculating a boundary temperature based on the heat transfer amount. In this case, in the steady analysis step, it is preferable to perform the steady analysis using the boundary temperature calculated in the boundary temperature calculation step.

( 5 ) The component temperature prediction device disclosed herein is a device that predicts the temperature of a component existing in the fluid region using thermal fluid analysis software.
The temperature prediction device is modeled by dividing a contact portion of the part with the fluid into a plurality of cells and modeling the solid part and a contact portion of the fluid with the part into a plurality of cells. A model setting unit for setting a fluid model, and for each cell of the fluid model, the fluid temperature of each cell and the wall surface temperature of each cell of the solid model adjacent to each cell are calculated by steady-state analysis. A map creation unit that creates a map in which the fluid temperature is expressed as a function of the wall surface temperature based on the fluid temperature and the wall surface temperature at a plurality of times, and the map creation unit for each cell of the solid model in calculating the heat transfer amount by transient analysis using the map created, and a temperature calculation section for calculating the temperature based on the total heat, the map creating unit before the fluid temperature With it approximated as a linear function of the wall temperature, to create the map in which a restricted function that limits the extrapolated value of the fluid temperature.

( 6 ) It is preferable that the map creation unit divides a time region in which the function is calculated for each cell of the solid model every time the heat transfer direction changes.

  According to the disclosed temperature prediction method for components, the components existing in the fluid region are divided into the fluid model and the solid model, and the steady analysis is performed on the fluid model, so that the calculation time can be greatly shortened. In addition, by creating a map in which the fluid temperature is expressed as a function of wall surface temperature from the fluid temperature and wall surface temperature at multiple time points obtained by steady analysis of the fluid model, adjacent to each cell of the solid model The fluid temperature, which is the temperature of each cell in the fluid model, can be derived. Thereby, the amount of heat transfer by convection can be calculated in the unsteady analysis.

Further, since each heat transfer amount by heat conduction and radiation can be calculated regardless of the fluid temperature, the temperature of each cell of the solid model can be calculated based on these heat transfer amounts. In other words, the amount of heat transferred by each of the three heat transfer modes can be calculated with high accuracy, so that the temperature of the component can be predicted with high accuracy, and the temperature change and temperature distribution of the component can also be predicted with high accuracy. It is. Furthermore, in the process of creating the map, the fluid temperature is approximated as a linear function of the wall surface temperature, and a limiting function for limiting the extrapolated value of the fluid temperature is provided, so that excessive or too low fluid temperature is prevented from being derived. be able to. As a result, the divergence of the analysis can be prevented, and the stability of the analysis can be ensured.

It is a schematic diagram for demonstrating the temperature prediction method of the components which concern on one Embodiment, (a) is a perspective view of a hanger rubber, (b) is the fluid model in the area | region R of Fig.1 (a), (c) is The solid model in the area | region R of Fig.1 (a) is shown. It is a block diagram which illustrates the composition of the temperature prediction device of the parts concerning one embodiment. It is a figure explaining the analysis process of the temperature prediction method of the component which concerns on one Embodiment. (A) is the graph which showed the change of the wall surface temperature of the solid side boundary cell corresponding to the point P of a hanger rubber, and the change of the fluid temperature of the fluid side boundary cell adjacent to this solid side boundary cell, (b) ) Is a graph showing the relationship of the fluid temperature to the wall surface temperature at each time point in FIG. 4A, and FIG. 4C is a graph obtained by dividing the time domain with respect to the graph of FIG. It is. It is an example of the map created by the map creation unit, in which (a) shows that the change in wall temperature and the change in fluid temperature are substantially the same, (b) shows the change in fluid temperature relative to the change in wall temperature. The case where the amount of change is large is shown. It is a graph which illustrates the temperature prediction result by the temperature prediction method of the parts concerning one embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. Note that the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described in the following embodiment. Each configuration of the following embodiments can be implemented with various modifications without departing from the spirit thereof, and can be selected as necessary or can be appropriately combined.

[1. Analysis model]
The part temperature prediction method and temperature prediction apparatus according to the present embodiment are a method and apparatus for predicting the temperature of a part existing in a fluid region using thermal fluid analysis software. In this embodiment, a hanger rubber that supports an exhaust pipe or a muffler of a vehicle on the vehicle body is taken as an example of a part, and the temperature change and temperature distribution of the hanger rubber when key-off (engine stop) is performed after steady running.

  As shown in FIG. 1 (a), the hanger rubber 1 to be analyzed is a rubber part disposed below the vehicle body floor, and a hole 1a to which a vehicle body side bracket (not shown) is connected. And a hole (not shown) to which a bracket 4 (hereinafter referred to as a hanger bracket 4) on the exhaust pipe 5 side indicated by a two-dot chain line is connected. Since the hanger rubber 1 is disposed immediately above the exhaust pipe 5, it is a component that is strongly affected by heat conduction from the hanger bracket 4 and radiation from the exhaust pipe 5 in addition to heat transfer by convection.

  Therefore, in order to predict the temperature of the hanger rubber 1 with high accuracy, it is necessary to calculate the heat amounts (heat transfer amounts) of the three heat transfer modes by unsteady analysis. However, when calculating the temperature of a component using a strongly coupled method that calculates heat conduction, radiation, and convection simultaneously as one system, enormous calculation resources and calculation time are required. Therefore, in this embodiment, a strong coupling method is not used, and a three-dimensional analysis model simulating the hanger rubber 1 is divided into a solid portion (that is, a model of the hanger rubber 1 itself) and a surrounding fluid portion (that is, a model of surrounding air). The calculation time is greatly shortened by performing unsteady analysis for the solid portion and steady analysis that does not calculate the state change for the fluid portion.

  An example of the analysis model is shown in FIGS. These drawings show the internal cross section of the model corresponding to the region R surrounded by the alternate long and short dash line in FIG. 1A, and FIG. 1B shows the fluid model 2 and FIG. Is solid model 3. The fluid model 2 is set by dividing the air region around the hanger rubber 1 into a plurality of cells 20 (calculation grids). Among the plurality of cells 20 of the fluid model 2, the cell 20 located at the contact portion with the hanger rubber 1 (that is, the boundary portion with the solid model 3) is particularly referred to as a fluid side boundary cell 21.

  The solid model 3 is set by dividing the hanger rubber 1 into a plurality of cells 30 (calculation grids). Among the plurality of cells 30 of the solid model 3, the cell 30 located at a contact portion with air (that is, a boundary portion with the fluid model 2) is particularly referred to as a solid-side boundary cell 31. Hereinafter, when the fluid side boundary cell 21 and the solid side boundary cell 31 are not particularly distinguished, they are simply referred to as boundary cells 21 and 31. In FIGS. 1B and 1C, reference numerals are given to some of the boundary cells 21 and 31.

  Various numerical data such as parameters for defining the size and shape of the cells 20, 30, parameters indicating temperature, parameters such as mass, specific heat and thermal conductivity are set in each of the plurality of cells 20, 30. Has been. The size, the number of divisions, the division position, etc. of each of the cells 20 and 30 are not particularly limited. For example, as shown in FIGS. 1B and 1C, the boundary cells 21 and 31 are set to be smaller than the other cells 20 and 30 at the boundary portion between the fluid model 2 and the solid model 3. Analysis accuracy may be increased. Further, the cell size may be set to increase as the distance from the boundary portion increases, or all cells may be set to substantially the same size.

[2. Device configuration]
The component temperature prediction apparatus of the present embodiment is realized by, for example, a general-purpose computer that can execute a computer program 17 for thermal fluid analysis. FIG. 2 is a schematic configuration diagram in the case of configuring a component temperature prediction apparatus using the computer 10. FIG. 3 is a diagram showing an analysis process performed using the computer 10.

  As shown in FIG. 2, a computer 10 (temperature prediction device) includes a CPU 11 (Central Processing Unit), a memory 12 [Read Only Memory (ROM), Random Access Memory (RAM), etc.], an external storage device 13 [Hard Disk Drive (HDD), Solid State Drive (SSD), optical drive, etc.], input device 14 (keyboard, mouse, etc.) and output device 15 (display, printer device, etc.). These are connected to be communicable with each other via a bus 16 (control bus, data bus, etc.) provided in the computer 10. The computer program 17 for numerical fluid analysis is installed in the external storage device 13.

  The CPU 11 reads the program installed in the external storage device 13 on the memory 12 and executes it, and outputs the calculation result to the output device 15. The shape of the hanger rubber 1 serving as an analysis model is set by diverting data created by, for example, general-purpose three-dimensional CAD (Computer Aided Design) software to the computer program 17 or by input from the input device 14. The initial conditions and boundary conditions of analysis, specific parameter setting values, etc. are set based on inputs from the input device 14 or as values given in advance.

  The function of the computer program 17 for numerical fluid analysis is schematically shown in FIG. The computer program 17 includes a model setting unit 17a, an initial condition setting unit 17b, an initial map creation unit 17c, a boundary temperature calculation unit 17d, a map creation unit 17e, and a temperature calculation unit 17f. Each of these elements may be realized by an electronic circuit (hardware), or a part of these functions may be provided as hardware and the other part may be software.

  The model setting unit 17a sets the analysis model described above. As shown in FIGS. 1B and 1C, the model setting unit 17a includes a fluid model 2 in which the air region around the hanger rubber 1 is divided into a plurality of cells 20 and the hanger rubber 1 is modeled. A solid model 3 divided into a plurality of cells 30 and modeled is set. Of the plurality of cells 20 and 30, cells located at the boundary between the fluid model 2 and the solid model 3 are set as a fluid-side boundary cell 21 and a solid-side boundary cell 31, respectively.

  The initial condition setting unit 17b sets initial conditions and boundary conditions used for analysis. In this embodiment, since it is assumed that the key is turned off after steady running, the initial condition setting unit 17b first calculates the temperature (stable temperature) of the hanger rubber 1 during steady running. For this calculation, a known method including the method described in Patent Document 1 described in the background art can be used. For example, create a full model that models all parts of the car body, analyze heat transfer of heat conduction, radiation, and convection at the same time, and calculate the equilibrium temperature for each cell included in the full model as the stable temperature of that cell. May be. The initial condition setting unit 17b sets the solid internal temperature Ts for all the cells 30 of the solid model 3 using the stable temperature.

Further, the initial condition setting unit 17b adds a value obtained by adding a constant value to all the solid surface temperatures T ₁ (stable temperature of the solid side boundary cell 31) for the interpolation calculation described later, and the second solid surface temperature T _2. And a value obtained by subtracting a certain value from all the solid surface temperatures T _{1 is} set as the third solid surface temperature T ₃ . The solid surface temperature T ₁ is a boundary condition given to all the solid side boundary cells 31. The second solid surface temperature T ₂ and the third solid surface temperature T ₃ are values that are arbitrarily set. The three solid surface temperatures T ₁ , T ₂ , and T ₃ are boundary conditions used in steady-state analysis. The solid internal temperature Ts is used in unsteady analysis by the boundary temperature calculation unit 17d described later.

The initial map creation unit 17c creates a map Mp (hereinafter referred to as an initial map Mp) for using the steady analysis result in the fluid model 2 for the unsteady analysis in the solid model 3, and all the fluid side For the boundary cell 21, one initial map Mp is created for each fluid-side boundary cell 21. First, the initial map creating unit 17c first sets the boundary conditions (that is, three solid surface temperatures T ₁ , T ₂ , T ₃ ) set by the initial condition setting unit 17b for each of the fluid side boundary cells 21 of the fluid model 2. Each is used for steady state analysis. Here, as shown in FIG. 3, for each fluid-side boundary cell 21, steady analysis 1-1 with the solid surface temperature T ₁ as an input value and steady analysis with the second solid surface temperature T ₂ as an input value. and 1-2, to implement and constant analysis 1-3 with an input value of the third solid surface temperature T _3.

The steady analysis here is, for example, when the solid surface temperature T ₁ which is one boundary condition is given, the temperature of each cell of the fluid model 2 having the boundary condition converges to what steady temperature. Or a numerical analysis of the distribution of the steady-state temperature. Each of the solid surface temperatures T ₁ , T ₂ , and T ₃ gives a temperature distribution at the boundary between the fluid model 2 and the solid model 3. Therefore, the amount of heat transfer between the fluid side boundary cell 21 located at the outermost shell of the fluid model 2 and the solid model 3 side adjacent thereto is determined by the solid surface temperatures T ₁ , T ₂ , T ₃ and the fluid side. It can be calculated based on the temperature of the boundary cell 21.

According to the above three steady-state analyses, for each fluid-side boundary cell 21, the heat transfer coefficient h, the temperature Tf of each fluid-side boundary cell 21 (hereinafter referred to as fluid temperature Tf), and the fluid-side boundary cell 21 are adjacent to each other. Three temperatures Tw (hereinafter referred to as wall surface temperature Tw) of each solid side boundary cell 31 are calculated. That is, as shown in FIG. 3, in the steady analysis 1-1, the heat transfer coefficient h ₁ , the fluid temperature Tf ₁ and the wall surface temperature Tw ₁ are calculated, and in the steady analysis 1-2, the heat transfer coefficient h ₂ and the fluid temperature Tf. ₂ and the wall surface temperature Tw ₂ are calculated, and in the steady analysis 1-3, the heat transfer coefficient h ₃ , the fluid temperature Tf _3, and the wall surface temperature Tw ₃ are calculated.

The initial map creation unit 17c displays three sets of wall temperature Tw and fluid temperature Tf [ie, coordinates (Tw ₁ , Tf) obtained by steady analysis in a graph with the wall surface temperature Tw on the horizontal axis and the fluid temperature Tf on the vertical axis. ₁ ), (Tw ₂ , Tf ₂ ), (Tw ₃ , Tf ₃ )] and plot an approximate line (regression line, interpolation function) using the least squares method, principal component analysis method, etc. A map Mp is created. The approximate straight line calculated here is a fluid temperature Tf expressed as a function of the wall surface temperature Tw. Thus, the ratio of the change amount of the fluid temperature Tf to the change amount of the wall surface temperature Tw (the change amount of the fluid temperature Tf / the change amount of the wall surface temperature Tw, that is, the inclination of the approximate line) is grasped for each fluid side boundary cell 21. be able to.

  The boundary temperature calculation unit 17d performs unsteady analysis on each of the solid side boundary cells 31 of the solid model 3 and calculates the wall surface temperature Tw of each solid side boundary cell 31 as the boundary temperature. The boundary temperature calculated here is used in the next map creation unit 17e. The boundary temperature calculation unit 17d calculates the heat transfer amount qt by heat conduction, the heat transfer amount qr by radiation, and the heat transfer amount qc by convection by unsteady analysis for each solid-side boundary cell 31, and these heat transfer amounts qt, qr, qc The wall surface temperature Tw is calculated on the basis of the total heat transfer amount q obtained by adding the above.

  The non-stationary analysis here refers to, for example, when the solid internal temperature Ts of the solid model 3 which is one initial condition is given, the temperature of each cell of the solid model 3 having the initial condition changes with time. It is a numerical analysis of how the temperature changes or the distribution of temperature.

The temperature of each cell of the solid model 3 is given as the solid internal temperature Ts set by the initial condition setting unit 17b. The solid internal temperature Ts does not include information on the ambient temperature at which the solid model 3 is surrounded, that is, the boundary condition at the boundary between the fluid model 2 and the solid model 3 is not determined. On the other hand, in the initial map Mp created by the initial map creation unit 17c, the fluid temperature Tf given as a function of the wall surface temperature Tw is expressed. That is, if the solid surface temperature T ₁ is substituted for the wall surface temperature Tw of this function, the fluid temperature Tf corresponding to the solid surface temperature T ₁ is calculated. Therefore, the amount of heat transfer between the solid side boundary cell 31 located in the outermost shell of the solid model 3 and the fluid model 2 side adjacent thereto can be calculated.

At this time, the boundary temperature calculation unit 17d outputs the calculated wall surface temperature Tw to the memory 12 as the boundary temperature T _N at that time (N represents the number of outputs) at several points during the calculation. For example, the wall surface temperature Tw and the boundary temperature _TN are output every tens of seconds after the unsteady analysis is started. When the unsteady calculation of the wall surface temperature Tw is performed at a predetermined time interval (for example, 900 [seconds]) starting from the time when the boundary temperature calculation unit 17d is keyed off after the steady running, the seven times during the unsteady calculation. If it is to round the output, so that the wall temperature Tw at each output time point is outputted as the boundary temperature _{T 1, T 2, ... T} 7 , respectively. Note that the number N of outputs is appropriately set in consideration of the balance between calculation accuracy and calculation load, and details will be described later. Since T _{1 to} T _N are parameters used in the steady analysis described later, here, they are expressed by the same symbols as the above-described solid surface temperatures T _{1 to} T ₃ .

  Here, the heat transfer amount qt due to heat conduction and the heat transfer amount qr due to radiation can be calculated only by calculation on the solid model 3 side, but the heat transfer amount qc due to convection is temperature information of the fluid model 2 adjacent to the solid model 3. Without it, you can't calculate. Therefore, the boundary temperature calculation unit 17d applies the solid internal temperature Ts set by the initial condition setting unit 17b as the wall surface temperature Tw to the initial map Mp created by the initial map creation unit 17c, so that the solid side boundary cell 31 The temperature Tf of the fluid side boundary cell 21 adjacent to is obtained. Then, by substituting the solid internal temperature Ts (for example, the temperature of the solid side boundary cell 31) as the wall surface temperature Tw and the fluid temperature Tf obtained from the initial map Mp into the following equation (1), the convective heat transfer amount qc is obtained. calculate.

Here, the heat transfer coefficient h in the equation (1) is the average value of the plurality of heat transfer coefficients h ₁ , h ₂ , h ₃ calculated by the initial map creation unit 17c, or the heat transfer coefficients h ₁ , A weighted average value obtained by applying a predetermined weighting process to h ₂ and h ₃ can be used. As a result of calculating the total heat transfer amount q, it is grasped how the temperature of each cell of the solid model 3 changes, and the solid internal temperature Ts in the calculation cycle is estimated. In the next calculation cycle, the heat transfer amount qc by convection is calculated based on the solid internal temperature Ts (temperature of the solid side boundary cell 31), and this is reflected in the total heat transfer amount q.

Similar to the initial map creation unit 17c, the map creation unit 17e creates a map M for using the steady analysis result in the fluid model 2 for the unsteady analysis in the solid model 3. For the side boundary cells 21, one map M is created for each fluid side boundary cell 21. However, the map creation unit 17e uses the boundary temperatures T ₁ , T ₂ ,... _TN at the respective time points output by the boundary temperature calculation unit 17d as conditions for steady analysis. That is, the map creation unit 17e uses the boundary temperatures T ₁ , T ₂ ,... _TN at each point of time output from the boundary temperature calculation unit 17d for each of the fluid side boundary cells 21 of the fluid model 2 to be stationary. Perform analysis. That is, the steady temperature of each cell (including each fluid-side boundary cell 21) of the fluid model 2 when the boundary temperatures T ₁ , T ₂ ,... _TN are given is calculated.

Here, as shown in FIG. 3, for each fluid-side boundary cell 21, steady analysis 2-1 using the boundary temperature T ₁ at the _first output time as the input value, the boundary temperature T ₂ at the second output time. A steady analysis 2-2 using the boundary temperature T _N at the output time of the Nth time as an input value is performed. By these N times of steady state analysis, for each fluid side boundary cell 21, the heat transfer coefficient h, the fluid temperature Tf of each fluid side boundary cell 21, and each solid side boundary cell 31 adjacent to each fluid side boundary cell 21. N wall surface temperatures Tw are calculated.

As shown in FIG. 5A, the map creating unit 17e displays N sets of wall surface temperatures Tw and fluid temperatures Tf obtained by steady analysis on a graph with the wall surface temperature Tw on the horizontal axis and the fluid temperature Tf on the vertical axis. [That is, the coordinates (Tw ₁ , Tf ₁ ), (Tw ₂ , Tf ₂ ),... (Tw _N , Tf _N )] are plotted, and an approximate straight line f ( A map M is created by calculating a regression line and an interpolation function. FIG. 5A is an example of a map M created by the map creation unit 17e. The wall temperature Tw on the horizontal axis and the fluid temperature Tf on the vertical axis are in the same temperature range (for example, 300 to 400 [K], etc.). ).

  Thus, the ratio of the change amount of the fluid temperature Tf to the change amount of the wall surface temperature Tw (the change amount of the fluid temperature Tf / the change amount of the wall surface temperature Tw, that is, the inclination of the approximate line f) is grasped for each fluid side boundary cell 21. can do. The approximate straight line f calculated here is a fluid temperature Tf expressed as a function of the wall surface temperature Tw, and is expressed by a linear function as in the following equation (2). In addition, a and b in Formula (2) are predetermined constants.

  Here, when calculating the approximate straight line f, the map creating unit 17e calculates the approximate straight line f each time the heat transfer direction of the solid-side boundary cell 31 changes (that is, a section in which interpolation is performed, an interpolation section). Separate. The heat transfer direction here means the direction in which heat is transmitted (moved), and the heat transfer direction of the solid side boundary cell 31 includes a direction to absorb heat (heat absorption) and a direction to release heat (heat dissipation). There are two forms. The change in the heat transfer direction of the solid side boundary cell 31 occurs when the magnitude relationship between the temperatures of the adjacent fluid side boundary cell 21 and the solid side boundary cell 31 is reversed. This is because the solid side boundary cell 31 absorbs heat if the temperature of the adjacent fluid side boundary cell 21 and the solid side boundary cell 31 is higher in the former, and the solid side boundary cell 31 releases heat if the latter is higher. Because.

This will be described with reference to FIGS. FIG. 4A shows the change in the wall surface temperature Tw of the solid side boundary cell 31 (hereinafter referred to as the solid side boundary cell 31p) corresponding to the point P of the hanger rubber 1 shown in FIG. It is the graph which illustrated change of fluid temperature Tf of fluid side boundary cell 21 (henceforth this is especially called fluid side boundary cell 21p) adjacent to cell 31p. Black circles and white squares in the graph are wall surfaces calculated by the map creation unit 17e through steady analysis using the boundary temperatures T ₁ , T ₂ ,... _TN output from the transient analysis by the boundary temperature calculation unit 17d. Temperature Tw and fluid temperature Tf are shown, respectively. That is, the plot time point in FIG. 4A substantially coincides with the output time point of the transient analysis by the boundary temperature calculation unit 17d.

  FIG. 4B is a graph showing the relationship of the fluid temperature Tf with respect to the wall surface temperature Tw at each time point in FIG. 4A, and FIG. 4C shows the time relative to the graph of FIG. The approximate straight line is calculated by dividing the area. In these drawings, the wall temperature Tw on the horizontal axis and the fluid temperature Tf on the vertical axis are set to the same temperature range (for example, 300 to 400 [K], etc.).

As shown in FIG. 4 (a), when the time of the key-off after steady running a time t _0, the wall temperature from time t ₀ is the first output time point Tw and the fluid temperature Tf of transient analyzes can temporarily rise. This is because the heat transfer amount qt (heat absorption amount) due to radiation from the exhaust pipe 5 and heat conduction from the hanger bracket 4 hardly changes immediately after the key-off, but the heat transfer amount qc (heat release amount) due to convection by eliminating running wind. This is because becomes smaller. Then, until after time t ₁ which is the output point of the third time, the wall temperature Tw is lower than the fluid temperature Tf, solid side boundary cell 31p is in the heat absorbing state.

However, at time t ₂ which is the output point of the fourth-time, higher than the wall temperature Tw is the fluid temperature Tf by reversed magnitude relation between wall temperature Tw and the fluid temperature Tf, the heat transfer direction to heat radiation from the heat absorption It has changed. At time t ₃ the is the output point five time immediately after, becomes lower than the re-wall temperature Tw is the fluid temperature Tf, the heat transfer direction is changed to heat absorption from the heat radiation. Further, at time t ₄ is the output point six round again wall temperature Tw is higher than the fluid temperature Tf, the heat transfer direction is changed to heat radiation from the heat absorption, then the heat dissipation state continues.

Therefore, as shown in FIG. 4B, the temporal relationship between the wall surface temperature Tw and the fluid temperature Tf is not a straight line but changes in a zigzag manner. That is, the wall surface temperature Tw and the fluid temperature Tf rise in the same way from time t ₀ to time t ₁ , but the magnitude relationship is switched at times t ₂ , t ₃ , and t ₄ , and from time t ₄ to time t It decreases again in the same way until ₅ . For the solid-side boundary cell 31 having such a complicated heat transfer form, the map creating unit 17e divides and divides the time region for calculating the approximate line f every time the heat transfer direction of the solid-side boundary cell 31 changes. A map M corresponding to each subsequent area is created individually.

Specifically, the map creation unit 17e determines the time at the previous output time when the magnitude relationship between the wall surface temperature Tw and the fluid temperature Tf at the current output time is opposite to the magnitude relationship at the previous output time. Separate areas. For example, in the example shown in FIG. 4 (a), since the magnitude relationship between the wall temperature Tw and the fluid temperature Tf at the time t ₂ is opposite to the magnitude relation at time t _1, the map creation unit 17e at time t ₁ , the time region is divided, and the time interval from time t ₀ to time t ₁ is, for example, time region A. Similarly, since the magnitude relationship between the two temperatures Tw and Tf at time t ₃ is opposite to the magnitude relationship at time t ₂ , the map creation unit 17e separates the time region at time t _{2 and} starts from time t _1. A time interval until time t ₂ is defined as a time region B. In this way, the map creation unit 17e divides the time region into regions A to E each time the heat transfer direction changes, and approximates straight lines f _A to F for each of the time regions A to E as shown in FIG. f _E is calculated. Here, although the approximate lines f _{A to} f _E are shown superimposed on one map M, these are set to individual maps M.

  Since the number N of output of the unsteady analysis results by the boundary temperature calculation unit 17d is the number of times of steady analysis by the map creation unit 17e, it matches the plot points when the map M is created. Therefore, if the number of times of output N is set to be small (that is, the time interval for output is set large), the time region (interpolation section) for calculating the approximate straight line f becomes large. It is difficult to capture the direction, and the temperature prediction error can be large.

  On the other hand, when the number N of outputs is set to be large, the error can be reduced because the output time interval is reduced. However, if the output number N is large, the number of times of steady analysis by the map creating unit 17e also increases. Therefore, the output count N is appropriately set in consideration of the balance between calculation accuracy and calculation load as described above. Since the N steady analyzes by the map creating unit 17e can be calculated independently, parallel processing is possible if there are sufficient calculation resources, and the time required for the calculation processing varies greatly even if the number of outputs N is large. It is not considered. For this reason, for example, when there are sufficient calculation resources, it is possible to set the number of outputs N larger to further increase the calculation accuracy.

Furthermore, in addition to the approximate straight line f, the map creation unit 17e calculates a limiting function g that limits the extrapolated value of the fluid temperature Tf with respect to the wall surface temperature Tw, and provides the limiting function g in the map M. The limiting function g is a function for limiting the fluid temperature Tf with respect to the wall surface temperature Tw within a predetermined range so that the fluid temperature Tf does not become excessive or excessive with respect to the wall surface temperature Tw, and is shown in FIG. As described above, there are one set on the high temperature side of the wall surface temperature Tw (limit function g _H on the high temperature side) and one set on the low temperature side of the wall surface temperature Tw (limit function g _L on the low temperature side). FIG. 5B is an example of the map M created by the map creation unit 17e, and the wall surface temperature Tw on the horizontal axis and the fluid temperature Tf on the vertical axis are in the same temperature range (for example, 300 to 400 [K], etc.). ).

The limiting function g _H on the high temperature side is expressed by the following equation (3-1), where Tw _{H is} the wall temperature of the point H where the wall surface temperature Tw is the highest among a plurality of plot points, and Tf _H is the fluid temperature. Expressed by a linear function. Further, the low-temperature side limiting function g _L is expressed by the following equation (3-2), where Tw _{L is} the wall surface temperature of the point L where the wall surface temperature Tw is the lowest among the plurality of plot points, and Tf _L is the fluid temperature. It is expressed as a linear function. The following two equations are for the case where the constant a of the approximate line f in Equation (2) is a positive value (a> 0). In addition, c in the following formula is a positive constant, and if c is set large, there is an advantage that the calculation accuracy of extrapolation becomes high, but there is a side that the calculation is likely to be unstable. And the stability of calculation are set as appropriate.

Note that the limiting function g ′ when the constant a of the approximate straight line f in Expression (2) is a negative value (a <0) is, for example, linear as shown in Expressions (3-3) and (3-4) below. It can be expressed as a function. Expression (3-3) is set on the high temperature side of the wall surface temperature Tw (high temperature side limiting function g _H ′), and Expression (3-4) is set on the low temperature side of the wall surface temperature Tw. (Restriction function g _L ′ on the low temperature side).

  That is, the limiting functions g and g ′ are calculated as linear functions having the same sign as the inclination a of the approximate line f. As a result, as shown in FIG. 5B, even when the approximate straight line f in which the fluid temperature Tf varies greatly with respect to the slight variation in the wall surface temperature Tw is calculated, the above equation (3- Since the extrapolated value of the fluid temperature Tf is limited by 1) to (3-4), the stability of the analysis is ensured.

  The temperature calculation unit 17f performs a non-stationary analysis for each of the solid-side boundary cells 31 of the solid model 3 and calculates a wall surface temperature Tw of each solid-side boundary cell 31 to obtain a temperature change. Similarly to the boundary temperature calculation unit 17d, the temperature calculation unit 17f calculates the heat transfer amount qt by heat conduction, the heat transfer amount qr by radiation, and the heat transfer amount qc by convection by unsteady analysis for each solid side boundary cell 31. The wall surface temperature Tw is calculated based on the total heat transfer amount q obtained by adding the heat transfer amounts qt, qr, and qc. Thereby, the temperature change of the hanger rubber 1 is estimated.

  As described above, since the heat transfer amount qc due to convection cannot be calculated without the temperature information of the fluid model 2 adjacent to the solid model 3, the temperature calculation unit 17f adds the initial condition to the map M created by the map creation unit 17e. The solid internal temperature Ts set by the setting unit 17b is applied as the wall surface temperature Tw to obtain the temperature Tf of the fluid side boundary cell 21 adjacent to the solid side boundary cell 31. At this time, the temperature calculation unit 17f refers to the real time and obtains the fluid temperature Tf by appropriately using the approximate straight line f and the limiting functions g and g ′ in the corresponding time region of the map M. The real time here means the elapsed time from the start point when the point of time when the key is turned off after the steady running is set as the start point of the non-steady state analysis.

For example, when calculating the temperature change for the solid side boundary cell 31p corresponding to the point P of the hanger rubber 1 shown in FIG. 1 by the unsteady analysis, the temperature calculation unit 17f displays the map M shown in FIG. It is used to obtain the fluid temperature Tf when the solid internal temperature Ts (for example, the temperature of the solid side boundary cell 31) is the wall surface temperature Tw. At this time, the temperature calculating section 17f is, during the period from the start of the transient analysis to the time t ₁ is calculated and approximated straight line f _A calculated in the time domain A, with respect to the approximate line f _A two The fluid temperature Tf is acquired by appropriately using two limiting functions g (not shown). That is, the temperature calculation unit 17f performs the unsteady analysis in accordance with the passage of time of the unsteady analysis in the boundary temperature calculation unit 17d.

Here, a method of selecting the approximate line f and the limit function g by the temperature calculation unit 17f will be described. First, as shown in FIG. 5B, a wall surface temperature Tw (solid internal temperature Ts) exists between a point H where the wall surface temperature Tw is the highest and a point L where the wall surface temperature Tw is the lowest among a plurality of plot points ( (Tw _L ≦ Tw ≦ Tw _H ), the temperature calculation unit 17f acquires the fluid temperature Tf using the approximate straight line f. On the other hand, when the wall surface temperature Tw is not within this range, it is determined from the sign of the slope a of the approximate line f and the magnitude relationship between the approximate line f and the limiting function g.

Specifically, when the slope a of the approximate straight line f is a positive value, that is, in the case of the map M as shown in FIG. 5B, the range in which the wall surface temperature Tw is higher than the point H (Tw _H <Tw ), The lower fluid temperature Tf is selected from the fluid temperature Tf acquired using the approximate straight line f and the fluid temperature Tf acquired using the limiting function g _H shown in Expression (3-1). In the range where the wall surface temperature Tw is lower than the point L (Tw <Tw _L ), the wall temperature Tw is acquired using the fluid temperature Tf acquired using the approximate straight line f and the limiting function g _L shown in Expression (3-2). Of the fluid temperatures Tf, the higher fluid temperature Tf is selected.

On the other hand, when the slope a of the approximate straight line f is a negative value, the fluid temperature Tf obtained using the approximate straight line f in the range where the wall surface temperature Tw is higher than the point H (Tw _H <Tw) and the equation (3) 3) Select a higher fluid temperature Tf from the fluid temperatures Tf acquired using the limiting function g _H ′ shown in FIG. In the range where the wall surface temperature Tw is lower than the point L (Tw <Tw _L ), the fluid temperature Tf obtained using the approximate straight line f and the restriction function g _L ′ shown in the equation (3-4) are used. The lower one of the fluid temperatures Tf is selected.

Then, the temperature calculation unit 17f calculates the convective heat transfer amount qc by substituting the solid internal temperature Ts as the wall surface temperature Tw and the fluid temperature Tf acquired from the map M into the above equation (1). In this case, the average value of the plurality of heat transfer coefficients h ₁ , h ₂ ,... H _N calculated by the map creation unit 17e is used as the heat transfer coefficient h in the equation (1).

[3. flowchart]
A procedure (temperature prediction method) when the computer 10 executes the computer program 17 will be described using the analysis process of FIG.

In step S10, data of the hanger rubber 1 serving as an analysis model is prepared or input from the external storage device 13, the input device 14, or the like, and the fluid model 2 and the solid model 3 are set by the model setting unit 17a. The initial condition setting unit 17b sets the solid internal temperature Ts, and three solid surface temperatures T ₁ , T ₂ and T ₃ are set.

In step S20, the initial map creation unit 17c performs steady analysis 1-1, 1-2, _1-3 using the three solid surface temperatures T ₁ , T ₂ , T ₃ set in step S10. For each fluid-side boundary cell 21, the heat transfer coefficient h, the fluid temperature Tf, and the wall surface temperature Tw are calculated three by three. In the following step S30, the initial map creation unit 17c plots the three wall surface temperatures Tw and the fluid temperature Tf obtained by steady analysis by plotting the wall surface temperature Tw on the horizontal axis and the fluid temperature Tf on the vertical axis. An approximate straight line is calculated using multiplication or the like, and an initial map Mp is created for each fluid-side boundary cell 21 (initial map creating step).

  In step S40, the boundary temperature calculation unit 17d performs the unsteady analysis 1 on each of the solid side boundary cells 31 of the solid model 3, and calculates the wall surface temperature Tw of each solid side boundary cell 31 as the boundary temperature (boundary Temperature calculation step). Then, after the unsteady analysis 1 is started, the calculated boundary temperature is output in predetermined time increments. In this calculation process, the solid internal temperature Ts set in step S10 and the initial map Mp created in step S30 are used when calculating the convective heat transfer amount qc.

In step S50, the map creation unit 17e performs steady-state analysis 2-1, 2-2,..., 2-N using the boundary temperature output in step S40, and the heat transfer coefficient for each fluid-side boundary cell 21. h, fluid temperature Tf, and wall surface temperature Tw are calculated for each N (steady state analysis step).
In subsequent step S60, the map creating unit 17e plots the N sets of wall surface temperatures Tw and fluid temperatures Tf obtained by steady analysis, with the wall surface temperature Tw on the horizontal axis and the fluid temperature Tf on the vertical axis. Each time the heat transfer direction changes, the time domain is divided, and within each time domain, an approximate straight line f is calculated by the least square method or the like, and a limiting function g is provided to map each fluid side boundary cell 21. M is created (map creation process).

  In step S70, the temperature calculation unit 17f performs the unsteady analysis 2 on each of the solid side boundary cells 31 of the solid model 3, and calculates the wall surface temperature Tw of each solid side boundary cell 31 to obtain a temperature change ( Temperature calculation step). In this calculation process, the map M created in step S60 is used. At this time, the fluid temperature Tf is set by appropriately using the approximate straight line f in the time domain corresponding to the real time of the unsteady analysis 2 and the limiting function g. To be acquired. In addition, since the wall surface temperature Tw of all the solid side boundary cells 31 is calculated in the unsteady analysis 2, in addition to the temperature change of the hanger rubber 1, temperature distribution is also calculated | required.

[4. Analysis results and effects]
FIG. 6 is a result of predicting how the temperature at the point P of the hanger rubber 1 shown in FIG. 1 changes from the time of key-off after steady running. A solid line graph indicates a temperature change predicted by the present temperature prediction method (this method) using the computer 10 described above, and a broken line graph indicates a temperature change predicted by strong coupling, which is a conventional method. As can be seen by comparing these two graphs, the temperature change predicted by this method is almost the same as the temperature change predicted by strong coupling, and this method has high calculation accuracy equivalent to that of strong coupling. Temperature prediction is possible.

  Note that the two-dot chain line graph in FIG. 6 shows changes in the boundary temperature calculated by the boundary temperature calculation unit 17d in the unsteady analysis. That is, the two-dot chain line graph shows the prediction result in the first transient analysis of this temperature prediction method. After performing the steady analysis of the fluid model 2 using this, the transient analysis of the solid model 3 is further performed. It is the graph which the temperature change estimated by performing is shown as a continuous line. From these graphs, the temperature prediction according to the present method can be performed with high accuracy equivalent to the temperature prediction by the strong coupling by performing the unsteady analysis on the solid model 3 in two stages.

  Therefore, according to the above-described temperature prediction method and temperature prediction apparatus, the part (the hanger rubber 1 in this embodiment) existing in the fluid region is divided into the fluid model 2 and the solid model 3, and the fluid model 2 is steady. Since the analysis is performed, the calculation time can be greatly reduced. In addition, by creating a map M in which the fluid temperature Tf is expressed as a function of the wall surface temperature Tw from the fluid temperature Tf and the wall surface temperature Tw at a plurality of times obtained by steady analysis of the fluid model 2, The fluid temperature Tf that is the temperature of each cell 21 of the fluid model 2 adjacent to each cell 31 of the model 3 can be derived. Thereby, the heat transfer amount qc by convection can be calculated in the unsteady analysis.

  Further, since the heat transfer amounts qt and qr due to heat conduction and radiation can be calculated regardless of the fluid temperature Tf, the temperature Tw of each cell 31 of the solid model 3 can be calculated based on these heat transfer amounts. That is, since the amount of heat transfer by the three heat transfer modes can be calculated with high accuracy, the temperature of the component 1 can be predicted with high accuracy, and thus the temperature change and temperature distribution of the component 1 can be also highly accurate. Predictable.

  Further, according to the temperature prediction method and the temperature prediction apparatus described above, a function (approximate straight line) is generated each time the heat transfer direction changes for each cell 31 of the solid model 3 in the map creation step (step S60) by the map creation unit 17e. Divide the time domain for calculating f). That is, since the relationship between the fluid temperature Tf and the wall surface temperature Tw is represented and mapped by a function taking the heat transfer direction into consideration, the calculation accuracy in the unsteady analysis of the solid model 3 can be improved. Thereby, even for a component having a complicated heat transfer form in which the heat transfer direction changes, the temperature change of the component can be estimated with the same high accuracy as that of the strong coupling method.

Further, in the above-described temperature prediction method, in the step of creating the map M, the fluid temperature Tf is approximated as a linear function of the wall surface temperature Tw, and the limiting function g for limiting the extrapolated value of the fluid temperature Tf is provided. Alternatively, it is possible to prevent the excessive fluid temperature Tf from being derived. As a result, the divergence of the analysis can be prevented, and the stability of the analysis can be ensured.
Furthermore, in the above-described temperature prediction method, the limiting function g is calculated as a linear function having the same sign as the slope a of the approximate line f, so that the analysis accuracy can be improved while ensuring the stability of the analysis.

  In the temperature prediction method described above, first, steady analysis is performed on each cell 21 of the fluid model 2 using a predetermined boundary condition, and an initial map Mp indicating the relationship between the fluid temperature Tf and the wall surface temperature Tw is created. Subsequently, for each cell 31 of the solid model 3, a transient analysis is performed using this initial map Mp to calculate the boundary temperature. In the steady analysis of the fluid model 2 performed when the map M is created, this boundary temperature is used. For this reason, as shown in FIG. 6, the temperature change (solid line) of the part that is finally predicted is the temperature of the part that is predicted by stronger coupling than the change of the boundary temperature (two-dot chain line) that is being calculated. It can approach the change (dashed line). That is, by performing the unsteady analysis in two stages, the temperature prediction accuracy of the part can be further increased.

[5. Others]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
In the above-described embodiment, the case where the fluid temperature Tf is expressed as a linear function of the wall surface temperature Tw in each step of creating the map M and the initial map Mp is exemplified. However, a plurality of wall surface temperatures Tw and fluid obtained by steady analysis are exemplified. The interpolation function for plotting the temperature Tf and calculating using the least square method or the like is not limited to a linear function, and may be another function such as a quadratic function or an exponential function.

  In the above embodiment, the fluid model 2 and the solid model 3 created by the model setting unit 17a are merely examples, and are not limited to those described above. For example, the solid model 3 may be modeled by dividing the contact portion of the hanger rubber 1 with the air into a plurality of cells, and the fluid model 2 is the air at the contact portion of the air and the hanger rubber 1. The area may be modeled by dividing it into a plurality of cells. That is, the fluid model 2 and the solid model 3 only need to include at least the fluid side boundary cell 21 and the solid side boundary cell 31 described above.

In the above embodiment, three solid surface temperatures T ₁ , T ₂ , and T ₃ are set as boundary conditions used by the initial condition setting unit 17b in the steady analysis, but even if four or more solid surface temperatures are set. Good.
Moreover, although the case where the map M corresponding to each area | region after a division | segmentation was produced individually was illustrated in the said embodiment, the several interpolation function and the some restriction | limiting function may be set to one map M. FIG.
In addition, when creating the map M, the area for calculating the interpolation function is divided every time the heat transfer direction changes. However, regardless of the change in the heat transfer direction, for example, the time area is divided every predetermined number of outputs. The interpolation function may be calculated.

  Further, the limiting function g is not essential, and may be a map that limits the range of the fluid temperature Tf by setting an upper limit value and a lower limit value of the fluid temperature Tf, for example. Moreover, in the said embodiment, when calculating the heat transfer amount qc by a convection, although the average value of the several heat transfer coefficient calculated in the initial map creation part 17c or the map creation part 17e is used, heat transfer coefficient h May not be an average value. For example, the convective heat transfer amount qc may be calculated using the heat transfer coefficient h calculated at a timing close to the real time with reference to the real time.

  In the above embodiment, the hanger rubber 1 provided in the exhaust system of the vehicle is illustrated as an analysis target. However, the temperature prediction target is not limited to this, and other exhaust systems such as the exhaust pipe 5 and the hanger bracket 4 are described. It may be a part or not a vehicle part. Also, the assumed situation of analysis is not limited to immediately after the key-off after the steady running described above, and it is possible to predict the temperature of parts in various situations by giving initial conditions and boundary conditions according to the situation where the analysis is performed. Furthermore, according to this method, even a complex part having a heat transfer mode can predict a temperature change and a temperature distribution with high accuracy while reducing a calculation time.

1 Hanger rubber (parts)
2 Fluid model 3 Solid model 10 Computer (temperature prediction device)
17 computer program 17a model setting unit 17b initial condition setting unit 17c initial map creating unit 17d boundary temperature calculating unit 17e map creating unit 17f temperature calculating unit 20 fluid model cell 21 fluid side boundary cell 30 solid model cell 31 solid side boundary cell
Tw Wall temperature
Tf Fluid temperature M map Mp initial map

Claims (6)

For a part existing in a fluid region, a solid model obtained by modeling the part of the part in contact with the fluid divided into a plurality of cells, and a part of the fluid in contact with the part divided into a plurality of cells. A method for predicting the temperature of the part by setting a modeled fluid model and using thermal fluid analysis software,
For each cell of the fluid model, a steady analysis step of calculating a fluid temperature of each cell and a wall surface temperature of each cell of the solid model adjacent to each cell by steady analysis;
A map creating step for creating a map in which the fluid temperature is expressed as a function of the wall surface temperature based on the fluid temperature and the wall surface temperature at a plurality of time points calculated in the steady analysis step;
For each cell of the solid model, the amount of heat transfer is calculated by unsteady analysis using the map created in the map creation step, and a temperature calculation step of calculating the temperature based on the amount of heat transfer is provided .
In the map creating step, the fluid temperature is approximated as a linear function of the wall surface temperature, and the map having a limiting function for limiting an extrapolated value of the fluid temperature is created. , Part temperature prediction method. 2. The component temperature prediction method according to claim 1, wherein in the map creation step, a time region in which the function is calculated is divided for each cell of the solid model every time a heat transfer direction changes . The restriction function is characterized in that the the slope the same sign of a linear function, the temperature predicting method component according to claim 1 or 2, wherein. For each cell of the fluid model, a plurality of fluid temperatures of the cells and wall surfaces of the cells of the solid model adjacent to the cells are calculated by steady analysis using predetermined boundary conditions, and the fluid temperature And an initial map creation step for creating an initial map showing the relationship between the wall temperature and the wall temperature,
For each cell of the solid model, a heat transfer amount is calculated by unsteady analysis using the initial map created in the initial map creation step, and a boundary temperature calculation step of calculating a boundary temperature based on the heat transfer amount is provided. ,
Wherein in the normal analysis process, characterized in that said performing the steady-state analysis using the boundary temperature calculated by the boundary temperature calculation step, the temperature predicting method component according to any one of claims 1-3. An apparatus for predicting the temperature of a part existing in a fluid region using thermal fluid analysis software,
A solid model in which a part of the part that contacts the fluid is divided into a plurality of cells and modeled, and a fluid model that is modeled by dividing the part of the fluid in contact with the part into a plurality of cells is set. A model setting section;
For each cell of the fluid model, the fluid temperature of each cell and the wall surface temperature of each cell of the solid model adjacent to each cell are calculated by steady analysis, and the fluid temperature and the wall surface at the calculated time points A map creating unit that creates a map based on temperature, in which the fluid temperature is expressed as a function of the wall surface temperature;
For each cell of the solid model, a heat transfer amount is calculated by unsteady analysis using a map created by the map creation unit, and a temperature calculation unit that calculates a temperature based on the heat transfer amount, and
The map creating unit creates the map provided with a limiting function for limiting the extrapolated value of the fluid temperature while approximating the fluid temperature as a linear function of the wall surface temperature. , Temperature prediction device for parts. The said map preparation part divides | segments the time area | region which calculates the said function, whenever the heat transfer direction changes about each cell of the said solid model, The temperature prediction apparatus of the components of Claim 5 characterized by the above-mentioned.

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