JP2010069506A - Flow analysis method and flow analysis device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flow analysis method for performing correct flow analysis. <P>SOLUTION: The flow analysis method with which a molten metal is packed into a die so as to produce a molding includes: stages (S100, S 200) in which initial temperature distribution of a liner installed in the die is recognized; and a stage (S300) in which flow analysis is performed in accordance with a heat conduction equation on the basis of the initial temperature distribution of the liner which has been recognized. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a flow analysis of a casting process.For example, by recognizing an initial temperature distribution of a liner, a volatile substance such as water entering from a mold-matching surface causes a defect when vacuum casting is performed. The present invention relates to a flow analysis method and a flow analysis apparatus that can know how to be involved very accurately.

  2. Description of the Related Art In recent years, when a casting product mold is manufactured, a computer-based simulation is performed in order to manufacture a mold that does not have a defect in hot water. For example, in Patent Document 1 below, the flow of molten metal into a mold is simulated, and as a result, how the molten metal is filled into the mold is visually observed, and the undulation at the molten metal at the tip of the molten metal is observed. Analyzing and examining the filling speed based on the phenomenon, etc., it helps to optimize the mold shape.

Further, in Patent Document 2 below, by replacing the air entrained in the closed region of the cavity of the mold with virtual particles, the molten metal is completely distributed to the cavity, and the simulation is more ideal by taking into account the entrained air. It is possible to create a typical mold.
JP-A-8-155625 JP 2002-283001 A

  However, the conventional technology as described above does not recognize the initial temperature distribution of the liner when casting the liner, and the conventional technology as described above considers air entrainment. However, it is not possible to perform a simulation in consideration of volatile substances such as water entering from the mold-matching surface of the mold, for example, when performing vacuum casting.

  In general, when casting a liner, a mold release agent is applied to the inner surface of the mold (upper mold and lower mold) before pouring the molten metal, and the molten metal is poured into the cavity by combining both molds. After the molten metal has solidified, the mold is opened, the product is taken out, and the inner surface of the mold is cleaned with a volatile substance such as water. At this time, the volatile substance scatters in and out of the mold, and remains in a place where the temperature of the depressed portion of the mold is low. This volatile material is purged with compressed air when the next casting is performed, but there are portions that are not completely blown away. The remaining volatile substances enter the cavity from the die-matching surface during vacuum casting, and interfere with the molten metal being introduced into the cavity. The molten metal that interferes with the volatile substance moves through the cavity as it is, and is finally located in a certain part of the product.

  Recent research has shown that the portion of the molten metal that interferes with volatile materials produces hydrogen gas defects that adversely affect welding. Therefore, if the initial temperature distribution of the liner when casting the liner can be recognized and the position and size of the hydrogen gas defects can be accurately grasped, it will help improve the quality of the cast product and create a more ideal mold. It should be.

  The present invention has been made to solve the above-described problems of the prior art, recognizes the initial temperature distribution of the liner when casting the liner, and volatiles such as water entering from the mold-matching surface. It is an object of the present invention to provide a flow analysis method and a flow analysis apparatus capable of more accurate flow analysis in consideration of substances.

  In order to achieve the above object, a flow analysis method according to the present invention is a flow analysis method of a process of manufacturing a molded product by filling a molten metal in a mold, and an initial temperature distribution of a liner installed in the mold And a flow analysis according to a heat conduction equation based on the recognized initial temperature distribution of the liner.

  In addition, a flow analysis method according to the present invention for achieving the above object is a flow analysis method of a process of manufacturing a molded product by filling a mold with a molten metal, and an initial stage of a liner installed in the mold Recognizing a temperature distribution; recognizing a temperature distribution on the surface of the mold before filling with the molten metal; extracting a region where the recognized temperature is a predetermined value or less; A step of disposing a volatile material in part, and starting the introduction of the molten metal into the mold by evacuation, and the volatilization sucked into the mold from the mold-matching surface of the mold by evacuation The step of starting the introduction of the volatile substance, and when the molten metal and the volatile substance interfere in the mold while the molten metal and the volatile substance are introduced into the mold. Dried Calculating the volume of the volatile material at the time, replacing the calculated volume of the volatile material with virtual particles, and adding the virtual particles until the molten metal is filled into the mold. And moving the molten metal together with the movement of the molten metal, and ending the introduction of the molten metal when the molten metal is filled in the mold.

Furthermore, a flow analysis method according to the present invention for achieving the above object is a flow analysis method of a process of manufacturing a molded product by filling a mold with a molten metal, and an initial stage of a liner installed in the mold Recognizing the temperature distribution, recognizing the temperature distribution of the mold surface before filling with the molten metal, extracting the region where the recognized temperature is below a certain value,
Arranging a volatile substance in a part of the extracted region; introducing the molten metal into the mold by evacuation; and introducing the volatile substance sucked from a mold-matching surface of the mold And moving the volatile substance with the movement of the molten metal until the molten metal is filled in the mold.

  A flow analysis apparatus according to the present invention for achieving the above object is a flow analysis apparatus for performing flow analysis of a process of manufacturing a molded product by filling a mold with molten metal, and installed in the mold. Liner temperature distribution recognition means for recognizing the initial temperature distribution of the liner, temperature distribution recognition means for recognizing the temperature distribution of the mold surface before filling the molten metal, and extracting the region where the recognized temperature is below a certain value A region extracting means for disposing the volatile material in a part of the extracted region, starting the introduction of the molten metal by evacuation into the mold, and evacuating the mold into the mold by evacuation; The introduction of the volatile substance sucked from the mold matching surface is started, and the molten metal and the volatile substance are introduced into the mold while the molten metal and the volatile substance are introduced into the mold. When the volatile substance interferes, the volume of the volatile substance at the time of the interference is calculated, the calculated volume of the volatile substance is replaced with virtual particles, and the molten metal is filled in the mold. And calculating means for moving the virtual particles with the movement of the molten metal until the molten metal is moved, and terminating the introduction of the molten metal when the molten metal is filled in the mold.

  The flow analysis method and flow analysis apparatus according to the present invention configured as described above recognizes the initial temperature distribution of the liner installed in the mold and considers volatile substances such as water entering from the mold-matching surface. Therefore, more accurate flow analysis is possible, which can be used for improving the quality of cast products and creating more ideal molds.

  The present embodiment will be described below. In this embodiment, as a premise of flow analysis, the temperature distribution of a liner (specifically, a cylinder liner) to be inserted into a mold is shown in FIG. The temperature distribution in at least one direction of the depth direction, the width direction, and the height method is recognized.

  For example, in FIG. 1A, in the depth direction of the liner inserted into the mold (X direction of the three-dimensional orthogonal coordinate system), at least one of the four liners is directed toward the X direction at a plurality of locations. A measured value is obtained by applying a thermometer. In FIG. 1B, the measured values are obtained by applying thermometers in the Y direction at a plurality of locations for four liners in the width direction (Y direction of the three-dimensional orthogonal coordinate system) of the liner inserted into the mold. Seeking. Further, in FIG. 1C, at least one of the four liners in the height direction of the liner inserted into the mold (the Z direction of the three-dimensional orthogonal coordinate system) is directed to a plurality of Z directions. The measured value is obtained by applying a thermometer.

  Thus, it is natural that the temperature distribution in the X, Y, and Z directions of each liner can be accurately recognized before casting the liner. Accuracy is improved. In the present invention, in order to obtain a flow analysis with further improved accuracy, the initial temperature distribution of the liner installed in the mold is recognized, and volatile substances such as water entering from the mold matching surface are also taken into consideration. ing.

  Therefore, according to the present embodiment, since flow analysis considering the initial temperature distribution of the liner can be performed, flow analysis with higher accuracy can be performed. As described above, it is most preferable to recognize the initial temperature distribution in the X, Y, and Z directions of the liner, but considering the productivity, equipment cost, and the accuracy of the flow analysis for them, the X, Y, and Z directions are considered. The initial temperature distribution may be recognized in any one or two directions. This is because if the flow analysis with satisfactory accuracy is possible, it is advantageous in terms of cost to have a smaller number of initial temperature distribution recognition directions.

  In the present embodiment, the temperature distribution based on the actually measured value of the liner obtained as described above is standardized as an experimental value or an experimental formula, and the standardized value or formula is used for the flow analysis. The liner temperature is exemplified by directly applying a thermometer. However, the present invention is not limited to this, and the temperature distribution of the liner may be measured using a thermometer such as thermography.

  Next, the general operation of the flow analysis method according to the present invention will be briefly described with reference to the flowcharts of FIGS.

  In the flowchart shown in FIG. 2, the initial temperature of the liner is obtained from actual measurement values obtained by repeating the experiment, and the flow analysis is performed using the actual measurement values.

  First, the temperature distribution of the liner immediately before casting is examined while the liner is set in the mold. This temperature distribution may be obtained from an actual measurement value obtained by repeating the experiment as described above, or from a sensor that can recognize the temperature distribution of the liner in real time (S100). .

  A conventionally known analysis model is created from the recognized temperature distribution of the liner, and analysis conditions are set. In this case, the measured value is input as the initial liner temperature (S200).

  Next, the temperature field is implemented according to the heat conduction equation. The implementation of the temperature field according to this heat conduction equation will be described in detail with reference to FIG. 4 and subsequent drawings (S300).

  Next, in the flowchart shown in FIG. 3, the initial temperature of the liner is obtained from a polynomial expressed by a temperature distribution curve as shown in FIG. 1 from an actual measurement value at an arbitrary point. Analysis is performed.

  First, the temperature distribution of the liner immediately before casting is examined while the liner is set in the mold. This temperature distribution may be obtained from an actual measurement value obtained by repeating the experiment as described above, or from a sensor that can recognize the temperature distribution of the liner in real time (S100). .

  Next, a conventionally known analysis model is created and analysis conditions are set. In this case, the initial temperature of the liner is given the temperature distribution of the liner using a three-dimensional polynomial represented by the temperature distribution curves shown in FIGS. (S200 '). If the initial temperature of the liner is expressed by a three-dimensional polynomial, the flow analysis using the three-dimensional polynomial can be directly performed by an analysis device using a computer.

  Next, the temperature field is implemented according to the heat conduction equation. The implementation of the temperature field according to this heat conduction equation will be described in detail with reference to FIG. 4 and subsequent drawings (S300).

  After obtaining the liner initial temperature distribution based on any of the above methods, the following flow analysis is performed in consideration of the initial temperature. In this embodiment, as an example of flow analysis, flow analysis considering volatile substances such as water entering from the mold-matching surface will be described, but it can be applied to other flow analysis. Of course.

  Hereinafter, based on the drawings, a flow analysis method and a flow analysis apparatus according to the present invention will be described by dividing them into [first embodiment] and [second embodiment]. FIG. 4 is a block diagram showing a schematic configuration of a simulation apparatus to which the flow analysis method according to the present invention (common to the first embodiment and the second embodiment) is applied.

  The simulation device 1 includes an analysis unit 11, a data storage device 12, an input device 13, and a display device 14.

  The analysis unit 11 simulates the flow of the molten metal and the volatile substance in consideration of the initial temperature distribution of the liner by the procedure described later, and also replaces virtual particles and displays casting defects (positions where hydrogen gas defects occur). , Display size). The analysis unit 11 functions as a temperature distribution recognition unit, a region extraction unit, and a calculation unit, and analyzes a preprocessor 31 that sets and prepares initial conditions for simulation, a solver 32 that actually executes simulation, and a simulation result. And a post processor 33 that performs processing for graphic display.

  The data storage device 12 stores initial temperature distribution of the liner and CAD data (design data) of the mold, and supplies data to the analysis unit 11 and also saves simulation results.

  The input device 13 is specifically a keyboard, a mouse, a thermotracer that detects the temperature of the mold, and the like, and inputs simulation conditions such as arrangement of volatile substances and time intervals of analysis steps, and temperature distribution of the mold surface. I do.

  Specifically, the display device 14 is a CRT, a liquid crystal display, or the like, and graphically displays the flow of the molten metal or the analysis result in the simulation.

Specifically, the simulation apparatus having the above-described configuration is realized by a computer such as a workstation or a personal computer executing a casting simulation program created according to the processing procedure of the present invention described later. The casting simulation program is usually provided by a computer-readable recording medium. However, the embodiment is not limited thereto, and for example, the casting simulation program is stored in a server computer, and the program is appropriately used as a terminal. It is possible to use various forms such as supplying to a functioning computer and executing a casting simulation program by the computer of this terminal.
[First Embodiment]
FIG. 5 is a subroutine flowchart of the flowchart of S300 shown in FIG. 2 or FIG. 3, and is a flowchart showing a processing procedure of the flow analysis method according to the first embodiment. In the flowchart, water is exemplified as a volatile substance.

  The analysis unit 11 receives a signal from a thermotracer that can detect the temperature of the mold, and recognizes the temperature distribution immediately before mold clamping on the surface of the actual mold based on the signal (S1). Based on the recognized temperature distribution of the mold, the analysis unit 11 extracts a region where the temperature during mold clamping is 100 ° C. or less. This is because volatile substances may accumulate in the region where the temperature is 100 ° C. or lower (S2).

  As shown in FIG. 6, the analyst uses a keyboard or mouse to place the volatile substance in a region where the temperature is 100 ° C. or less (a hollow portion where the volatile substance easily accumulates). As described above, each time the cast product is removed from the mold, the inner surface of the mold is cleaned with a volatile substance. The volatile substance used for cleaning accumulates in the indentation at a temperature of 100 ° C. or lower. easy. The analyst investigates in which part of the mold a volatile substance is likely to be accumulated in a casting operation that is usually performed, and arranges the volatile substance based on the investigation result. The arrangement of the volatile substance is performed by defining the center of gravity coordinate of the volatile substance and the radius (size of the volatile substance) from the center of gravity coordinate, and setting the flow rate to F = 2. When arranging a volatile substance in an analysis model, it arranges simply as shown in Drawing 7A. In this embodiment, the analyst arranges the volatile substance based on the survey result, but the survey result may be stored in the data storage device 12 (S3).

The analyst inputs data necessary for analysis, such as mesh conditions and time intervals of analysis steps, using a keyboard and a mouse. Here, the mesh condition is for determining what analysis density to simulate for the mold. For example, in the case of a three-dimensional orthogonal coordinate system, each of the X, Y, and Z axes. Determine mesh spacing. In a normal case, the mesh intervals of the X, Y, and Z axes are the same (S4).
The preprocessor 31 of the analysis unit 11 reads the CAD data of the mold stored in the data storage device 12 to create an analysis model, and sets and prepares initial conditions for simulation. Note that the analysis model is created by a conventionally used method (S5). Subsequently, a casting simulation by the solver 32 is performed. This simulation basically uses flow field analysis simulation, and the molten metal is filled into the mold based on the input design data for each cell set by the mesh conditions, and the volatile substances move. The process of going is simulated for each set time step. The simulation is performed using a free surface transport equation as shown below.

  In this transport equation, F represents a fluid ratio, F = 0 for a mesh in a cavity region not filled with molten metal, and F = 0-0.1 for a mesh at an interface where molten metal and gas are mixed. However, F = 1 is set for the mesh in the cavity region where the molten metal is filled, and F = 2 is set for the mesh in the region where the volatile substance is present (S6).

  The molten metal and volatile substances are moved on the free surface in time steps. In the case of vacuum casting, since the melt is introduced by evacuating the cavity, the volatile material remaining outside the mold is sucked from the mold-matching surface between the mold and the mold as shown in FIG. 7B. (S7). During the simulation, it is determined whether or not the volatile substance interferes with the molten metal. As shown in FIG. 7C, the interference between the volatile substance and the molten metal is performed by determining whether or not the mesh set to F = 1 and the mesh set to F = 2 are adjacent to each other ( S8).

  If interference between the volatile substance and the molten metal is detected (S8: YES), the volume of the volatile substance at that time is calculated. The volume of the volatile substance can be easily calculated by integrating the number of meshes set to F = 2. The calculated volume is temporarily stored in the data storage device 12 (S9). Next, the volatile substance portion is replaced with virtual particles as shown in FIG. 7D. In the process of replacing with virtual particles, the mesh set to F = 2 is changed to F = 1, the center of gravity of the changed region is obtained, and small virtual particles such as dots are arranged at the center of gravity. Completion (S10). Next, the virtual particles are moved based on the transport equation (S11).

  Next, when the movement of the virtual particles is completed, or when it is determined in step S8 that the volatile substance does not interfere with the molten metal (S8: NO), whether the analysis termination condition is satisfied (mold) Whether or not the filling rate of the molten metal introduced into the cavity becomes 99% or more). This determination is based on the number of meshes indicating the molten metal (the number of meshes set to F = 1), the number of meshes indicating the molten metal (the number of meshes set to F = 1) and the space of the cavity. This is done by dividing by the sum of the number of meshes shown (the number of meshes set to F = 0) and calculating whether the value is 0.99 or more (S12). If the analysis end condition is not satisfied (S12: NO), it is necessary to continue the simulation. Therefore, the analysis step time is incremented, the process returns to the step S6, and the processes of the steps S6 to S11 are repeated again. By repeatedly performing the processing of steps S6 to S11, the virtual particles move together with the molten metal.

  On the other hand, if the analysis end condition is satisfied (S12: YES), the solver 32 ends the flow analysis simulation (S13). As shown in FIG. 7E, the post processor 33 displays the location where the virtual particles finally arrived on the display device 14 as a result of the simulation, and also stores the volatile data stored in the data storage device 12 around the virtual particles. A region corresponding to the volume of the active substance is displayed on the display device 14. When the analysis result is displayed in this manner, it can be visually observed that a hydrogen gas defect is generated in the displayed portion in the template that is the object of the simulation (S14).

According to the above embodiment, the initial temperature distribution of the liner installed in the mold is recognized, and volatile substances such as water entering from the mold-matching surface are also taken into account, enabling more accurate flow analysis. Therefore, it can be used to improve the quality of cast products and to create more ideal molds.
[Second Embodiment]
FIG. 8 is a flowchart illustrating a processing procedure of the flow analysis method according to the second embodiment. Unlike the first embodiment, the present embodiment performs flow analysis without using virtual particles.

  The analysis unit 11 receives a signal from a thermotracer that can detect the temperature of the mold, and recognizes the temperature distribution immediately before mold clamping on the surface of the actual mold based on the signal (S21). Based on the recognized temperature distribution of the mold, the analysis unit 11 extracts a region where the temperature during mold clamping is 100 ° C. or less (S22).

  As shown in FIG. 9, the analyst uses a keyboard or a mouse to place a volatile substance in a region where the temperature is 100 ° C. or less (a hollow part where volatile substances are likely to accumulate). The analyst investigates in which part of the mold a volatile substance is likely to be accumulated in a casting operation that is usually performed, and arranges the volatile substance based on the investigation result. Arrangement of the volatile material is performed by setting its fluid rate to F = 2. When disposing a volatile substance in the analysis model, it is simply disposed as shown in FIG. 9A. In this embodiment, the analyst arranges the volatile substance based on the investigation result, but the investigation result may be stored in the data storage device 12 (S23). The analyst inputs data necessary for analysis, for example, mesh conditions and time intervals of analysis steps, using a keyboard and a mouse (S24).

  The preprocessor 31 of the analysis unit 11 reads the CAD data of the mold stored in the data storage device 12 to create an analysis model, and sets and prepares initial conditions for simulation. Note that the analysis model is created by a generally used method (S25).

  Subsequently, a casting simulation by the solver 32 is performed. This simulation basically uses flow field analysis simulation, and the molten metal is filled into the mold based on the input design data for each cell set by the mesh conditions, and the volatile substances move. The process of going is simulated for each set time step. The simulation is performed by solving simultaneous equations using a mass conservation equation, a momentum conservation equation, and an energy conservation equation as shown below.

  The simulations performed in these conservation equations are general ones that have been performed conventionally, and are performed while mixing the molten metal and volatile substances (the value of density ρ differs between the molten metal and volatile substances) ( S26).

  The molten metal and volatile substances are moved on the free surface in time steps. In the case of vacuum casting, since the melt is introduced by evacuating the cavity, the volatile material remaining outside the mold is sucked from the mold-matching surface between the mold and the mold as shown in FIG. 9B. (S27).

  The simulation with the volatile substance and the molten metal mixed is continued, and it is determined whether the filling rate of the molten metal introduced into the mold cavity is 99% or more (whether the analysis end condition is satisfied). The This determination is made by dividing the number of meshes showing the molten metal by the sum of the number of meshes showing the molten metal and the number of meshes showing the cavity space, and calculating whether the value is 0.99 or more. (S28).

  If the filling rate is not 99% or more (S28: NO), it is necessary to continue the simulation. Therefore, the analysis step time is incremented, the process returns to the step of S26, and the processes of the steps of S26 and S27 are repeated again. By repeatedly performing the processes of steps S26 and S27, both the molten metal and the volatile substance move.

  On the other hand, if the filling rate is 99% or more (S28: YES), the solver 32 ends the simulation of the flow analysis (S29). As a result of the above simulation, the post processor 33 displays on the display device 14 the location and size of the volatile substance sucked from the mold-matching surface between the mold and the final mold as shown in FIG. 9C. Let When the analysis result is displayed in this manner, it can be visually observed that a hydrogen gas defect is generated in the displayed portion in the template that is the object of the simulation (S30).

  As described above, in the present invention, the initial temperature distribution of the liner installed in the mold is recognized, and volatile substances such as volatile substances entering from the mold-matching surface are also considered, so that more accurate flow analysis Can be used to improve the quality of cast products and to create more ideal molds.

The present invention can be used particularly in the field of flow analysis of vacuum casting.

It is a figure which shows typically the temperature distribution of a liner. It is a flowchart which shows the procedure of the flow analysis method which concerns on this invention. It is a flowchart which shows the procedure of the flow analysis method which concerns on this invention. It is a block diagram which shows schematic structure of the simulation apparatus to which the flow analysis method based on this invention is applied. It is a flowchart which shows the process sequence of the flow analysis method which concerns on 1st Embodiment. It is a figure where it uses for description of the flow analysis method which concerns on 1st Embodiment. It is a figure where it uses for description of the flow analysis method which concerns on 1st Embodiment. It is a figure where it uses for description of the flow analysis method which concerns on 1st Embodiment. It is a figure where it uses for description of the flow analysis method which concerns on 1st Embodiment. It is a figure where it uses for description of the flow analysis method which concerns on 1st Embodiment. It is a figure where it uses for description of the flow analysis method which concerns on 1st Embodiment. It is a flowchart which shows the process sequence of the flow analysis method which concerns on 2nd Embodiment. It is a figure where it uses for description of the flow analysis method which concerns on 2nd Embodiment. It is a figure where it uses for description of the flow analysis method which concerns on 2nd Embodiment. It is a figure where it uses for description of the flow analysis method which concerns on 2nd Embodiment.

Explanation of symbols

1 simulation equipment,
11 Analysis Department
12 data storage device,
13 input devices,
14 display device,
31 preprocessor,
32 Solver,
33 Postprocessor.

Claims (11)

A flow analysis method for a process of manufacturing a molded product by filling molten metal in a mold,
Recognizing the initial temperature distribution of the liner installed in the mold;
Performing flow analysis according to a heat conduction equation based on the recognized initial temperature distribution of the liner;
A flow analysis method comprising:   2. The flow analysis method according to claim 1, wherein the initial temperature distribution of the liner recognizes the temperature distribution in at least one of a height method, a width direction, and a depth direction of the liner for at least one liner.   The flow analysis method according to claim 2, wherein the temperature distribution is expressed by a three-dimensional polynomial by actually measuring an arbitrary point of the liner. A flow analysis method for a process of manufacturing a molded product by filling molten metal in a mold,
Recognizing the initial temperature distribution of the liner installed in the mold;
Recognizing the temperature distribution on the surface of the mold before filling with the molten metal;
Extracting a region where the recognized temperature is below a certain value;
Placing volatile materials in a portion of the extracted area;
Starting the introduction of the molten metal into the mold by evacuation and starting the introduction of the volatile material sucked from the mold-matching surface of the mold into the mold by evacuation;
When the molten metal and the volatile substance interfere in the mold while the molten metal and the volatile substance are introduced into the mold, the volume of the volatile substance at the time of interference A step of calculating
Replacing the calculated volume of the volatile material with virtual particles;
Moving the virtual particles with the movement of the molten metal until the molten metal is filled into the mold;
Ending the introduction of the molten metal once the molten metal is filled into the mold;
A flow analysis method comprising: A flow analysis method for a process of manufacturing a molded product by filling molten metal in a mold,
Recognizing the initial temperature distribution of the liner installed in the mold;
Recognizing the temperature distribution on the surface of the mold before filling with the molten metal;
Extracting a region where the recognized temperature is below a certain value;
Placing volatile materials in a portion of the extracted area;
Introducing the molten metal into the mold by evacuation and introducing the volatile material sucked from the mold matching surface of the mold; and
Moving the volatile material with movement of the molten metal until the mold is filled with the molten metal;
A flow analysis method comprising: After the step of moving the virtual particles together with the movement of the molten metal, further estimating that a defect is generated in a portion where the virtual particles have finally moved; and
Displaying a portion where the defect occurs;
The flow analysis method according to claim 4 or 5, characterized by comprising:   The flow analysis method according to claim 4, wherein the volatile substance is water.   6. The flow analysis method according to claim 4, wherein the flow analysis is performed using a Naviestokes equation (NS). A flow analysis apparatus for performing flow analysis of a process of manufacturing a molded product by filling a mold with molten metal,
Liner temperature distribution recognition means for recognizing the initial temperature distribution of the liner installed in the mold,
Temperature distribution recognition means for recognizing the temperature distribution of the surface of the mold before filling with the molten metal;
Area extraction means for extracting an area where the recognized temperature is below a certain value;
A volatile substance is disposed in a part of the extracted region, and the introduction of the molten metal is started by evacuation into the mold and sucked from the mold-matching surface of the mold by the evacuation into the mold. When the molten metal and the volatile substance interfere in the mold while the molten metal and the volatile substance are introduced into the mold. Calculates the volume of the volatile substance at the time of interference, replaces the calculated volume of the volatile substance with virtual particles, and melts the virtual particles until the molten metal is filled in the mold. An arithmetic means that moves together with the movement of the metal and terminates the introduction of the molten metal when the molten metal is filled in the mold,
A flow analysis apparatus comprising:   The flow analysis apparatus according to claim 9, wherein the initial temperature distribution of the liner recognizes the temperature distribution in at least one of a height method, a width direction, and a depth direction of the liner for at least one liner.   The flow analysis method according to claim 10, wherein the temperature distribution is expressed by a three-dimensional polynomial by actually measuring an arbitrary point of the liner.

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