Water jacket boiling correction method, system and equipment and storage medium

Abstract

The invention discloses a water jacket boiling correction method, system and equipment and a storage medium, belongs to the technical field of engine heat transfer analysis, and solves the technical problem of poor precision of traditional heat transfer analysis. The method comprises the steps that the water side wall face temperature tw is calculated in real time through a subprogram, when tw exceeds the set temperature, the heat exchange coefficient HTC is corrected according to the temperature difference between the wall face temperature and the cooling liquid temperature, the correction equation is H = h + (18000-h) * (tw-120) / (180-120), h is the HTC provided by CFD simulation, and H is the corrected heat exchange coefficient; the set temperature is 120 DEG C; and the heat exchange coefficient HTC is automatically corrected through the FORTRAN subprogram. According to the method, the process of increasing the water jacket nucleate boiling heat transfer coefficient can be simulated, and the calculation precision is higher.

Description

Technical Field

[0001] This invention relates to the field of engine heat transfer analysis technology, and more specifically, to a water jacket boiling correction method, system, device, and storage medium. Background Art

[0002] With the development of technology, CAE (Computer Aided Engineering) simulation analysis has become an important tool in engine development. For example, fluid-structure interaction analysis can be used to obtain the temperature field distribution of an engine under operating conditions. The workflow is as follows: Fluid engineers first perform in-cylinder combustion CFD (Computational Fluid Dynamics) analysis to obtain the combustion gas wall temperature and heat transfer coefficient, and water jacket CFD analysis to obtain the coolant wall temperature and heat transfer coefficient. The instantaneous wall heat transfer information from the CFD analysis results is averaged over a period of time (such as one cycle) and then transmitted to the structural engineer. The structural engineer uses the heat transfer information transmitted by the fluid engineer as a third type of boundary condition and uses FEA (Finite Element Analysis) software to perform heat transfer analysis to solve for the temperature field. For example, the temperature field can be solved by performing heat transfer analysis using ABAQUS (a finite element software for engineering simulation).

[0003] However, traditional heat transfer analysis does not consider the boiling heat transfer phenomenon in the water jacket, and the applied water-side boundary (temperature, heat transfer coefficient) is fixed, which will affect the calculation accuracy. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the above-mentioned shortcomings of the prior art. The purpose of the present invention is to provide a water jacket boiling correction method that can improve the calculation accuracy.

[0005] The second objective of this invention is to provide a water jacket boiling correction system.

[0006] The third objective of this invention is to provide a computer device.

[0007] The fourth objective of this invention is to provide a computer storage medium.

[0008] To achieve the above objective, this invention provides a water jacket boiling correction method, which calculates the water-side wall temperature tw in real time through a subroutine. When tw exceeds the set temperature, the heat transfer coefficient HTC is corrected based on the temperature difference between the wall temperature and the coolant temperature.

[0009] As a further improvement, the corrected equation is: H=h+(18000-h)*(tw-120) / (180-120), where h is the HTC provided by the CFD simulation and H is the corrected heat transfer coefficient.

[0010] Furthermore, the set temperature is 120°C.

[0011] Furthermore, the modification is implemented through FORTRAN subroutines, and the specific process includes the following steps:

[0012] Step 1. Modify the water jacket boundary file. Obtain the water jacket boundary file provided by the fluid engineer. Add NU after the unit face number in the water jacket boundary file, that is, change F1 to F1NU. This indicates that the heat transfer coefficient is no longer uniform and constant, but is variable in real time based on subroutine calculation.

[0013] Step 2. Extract the number of parts and convert the part's own unit number to the ABAQUS internal unit number. The calculation formula is that the internal unit number of a part is equal to the sequence number of its own unit number plus the number of units of all the parts preceding it in ABAQUS.

[0014] Step 3. Write the data source .dat file. Write a FORTRAN-readable data source .dat file based on the water jacket boundary file.

[0015] Step 4. Merge the data source .dat files.

[0016] If there are multiple water jacket boundary files, repeat step 3 until all water jacket boundary files are compiled into a FORTRAN-readable data source dat file.

[0017] Run the edited data source dat file to generate the subroutine data source dat file required by the FORTRAN subroutine;

[0018] The generated subroutine data source dat files are merged into one file to form the final callable data source dat file of the FORTRAN subroutine;

[0019] Step 5. Edit the subroutine.for file, view the merged data source dat from Step 4, assign the number of lines in the file to N and the file path to File, and the FORTRAN subroutine will be edited.

[0020] Step 6. Import the calculation .inp file into the Job module, specify the FORTRAN subroutine edited in Step 5 under the General tab, and then submit the calculation.

[0021] Furthermore, in step 1, F1 to F4 are all replaced one-to-one with F1NU to F4NU.

[0022] Furthermore, in step 2, the number of units for all parts in ABAQUS is extracted using a Python program. Specifically, the CAE model is opened, and instances are traversed to obtain the number of units and nodes for all parts.

[0023] Furthermore, in step 3, the water jacket boundary file is written into a FORTRAN-readable data source dat file using a Python program. The specific process is as follows: Open "Write User Subroutine dat file.py", and define the data source dat file name, fluid water side boundary file name, part name, and element quantity parameter required for FORTRAN subroutine calculation according to the actual situation.

[0024] To achieve the second objective mentioned above, the present invention provides a water jacket boiling correction system, comprising:

[0025] The modification module is used to modify the water jacket boundary file. It obtains the water jacket boundary file provided by the fluid engineer and adds NU after the unit face number in the water jacket boundary file, that is, F1 is changed to F1NU. This indicates that the heat transfer coefficient is no longer uniform and constant, but is variable in real time based on subroutine calculation.

[0026] The extraction module is used to extract the number of parts and convert the part's own unit number into an ABAQUS internal unit number. The calculation formula is that the internal unit number of a part is equal to the sequence number of its own unit number plus the number of units of all the parts preceding it in ABAQUS.

[0027] Write a module to write data source .dat files, and write FORTRAN-readable data source .dat files based on water jacket boundary files;

[0028] The merge module is used to merge data source .dat files.

[0029] If there are multiple water jacket boundary files, repeat step 3 until all water jacket boundary files are compiled into a FORTRAN-readable data source dat file.

[0030] Run the edited data source dat file to generate the subroutine data source dat file required by the FORTRAN subroutine;

[0031] The generated subroutine data source dat files are merged into one file to form the final callable data source dat file of the FORTRAN subroutine;

[0032] The editing module is used to edit the subroutine.for file, view the merged data source dat in step 4, assign the file line number to N and the file path to File, and the FORTRAN subroutine can be edited.

[0033] The calculation module is used to import the calculation .inp file into the Job module. Under the General tab, specify the FORTRAN subroutine edited in step 5, and then submit the calculation.

[0034] To achieve the above-mentioned objective three, the present invention provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the above-mentioned water jacket boiling correction method.

[0035] To achieve the fourth objective mentioned above, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the aforementioned water jacket boiling correction method.

[0036] Beneficial effects

[0037] Compared with the prior art, the advantages of this invention are as follows:

[0038] In this invention, when the water-side wall temperature exceeds 120°C, the nucleation boiling correction formula begins to take effect. The correction equation is automatically calculated and corrected through FORTRAN subroutines, which can effectively simulate the process of increasing the water jacket nucleation boiling heat transfer coefficient and achieve higher calculation accuracy. Attached Figure Description

[0039] Figure 1 This is a flowchart of the present invention.

[0040] Figure 2 This is a screenshot of the Job interface. Detailed Implementation

[0041] The present invention will be further described below with reference to specific embodiments shown in the accompanying drawings.

[0042] Traditional heat transfer analysis does not consider boiling heat transfer in water jackets. The applied water-side boundary (temperature, heat transfer coefficient) is fixed, which affects the accuracy of calculations. Boiling heat transfer refers to the phenomenon where, when the water jacket wall temperature exceeds the coolant saturation temperature and the temperature difference reaches a certain level, bubbles are generated in the coolant, leading to an increase in the heat transfer coefficient. Nucleus boiling typically begins when the temperature difference reaches 4°C. As the temperature difference increases, this phenomenon becomes more intense, and the heat transfer coefficient increases significantly. However, when the temperature difference exceeds a certain value, the heat transfer coefficient decreases because the bursting bubbles form a thin air film on the boundary layer, hindering heat transfer. Nucleus boiling begins to transition to film boiling; this stage is also called transition boiling. With further increases in temperature difference, radiative heat transfer becomes dominant, and the heat transfer coefficient begins to increase again.

[0043] See Figures 1-2 To improve calculation accuracy, this invention provides a water jacket boiling correction method to simulate the process of increasing the water jacket nucleation boiling heat transfer coefficient. The method calculates the water-side wall temperature tw in real time through a subroutine. When tw exceeds the set temperature, the heat transfer coefficient HTC is corrected based on the temperature difference between the wall temperature and the coolant temperature.

[0044] The corrected equation is: H=h+(18000-h)*(tw-120) / (180-120), where h is the HTC provided by the CFD simulation and H is the corrected heat transfer coefficient.

[0045] In this embodiment, the temperature is set to 120°C.

[0046] The correction is implemented through FORTRAN subroutines, and the specific process includes the following steps 1 to 6:

[0047] Step 1. Modify the water jacket boundary file. In order to achieve boiling correction and make the subroutine work, you need to obtain the water jacket boundary file provided by the fluid engineer. Add NU after the cell face number in the water jacket boundary file, that is, change F1 to F1NU. This indicates that the heat transfer coefficient is no longer uniform and constant, but is variable in real time based on the subroutine calculation.

[0048] The water jacket boundary file format provided by the fluid engineer is as follows:

[0049] **Element No,FACE No,Tfluid[Celsius],HTC[W / mm^2K]

[0050] *FILM

[0051] mypipe-1.21889,F1,97.114,0.193E-01# Before modification

[0052] mypipe-1.21889,F1NU,97.114,0.193E-01# Modified

[0053] ...

[0054] Of course, you need to replace all F1 to F4 with F1NU to F4NU one by one.

[0055] Step 2. Extract the number of elements in the part. The element number in the fluid boundary file is the element number of the part corresponding to that boundary. When the part is imported into the ABAQUS software, ABAQUS will reorder all parts in the model starting from 1. In this way, each part has an internal element number. The FORTRAN subroutine needs to access the external data and the internal data in the ABAQUS solver in real time during operation. The element number must be consistent to ensure the accuracy of the calculation.

[0056] Therefore, it is necessary to convert the part's own cell number to the ABAQUS internal cell number. The calculation formula is that the part's internal cell number is equal to the sequence number of its own cell number plus the number of cells of all the parts preceding it in ABAQUS.

[0057] To facilitate cell number conversion, it's necessary to extract the cell count of all parts in ABAQUS. This can be done using a Python program: open the CAE model, iterate through the instances, and obtain the cell and node counts of all parts.

[0058] Step 3. Write the data source dat file. The subroutine correction equation requires the water jacket boundary file provided by the fluid engineer as input. However, the water jacket boundary file cannot be directly read by FORTRAN and needs to be converted to be recognized. Therefore, it is necessary to write a FORTRAN-readable data source dat file based on the water jacket boundary file.

[0059] This document describes how to convert a water jacket boundary file into a FORTRAN-readable data source (.dat) file using a Python program. The specific process involves opening "Write User Subroutine .dat file.py" and defining the necessary FORTRAN subroutine calculation parameters, including the data source (.dat) filename, the fluid water-side boundary filename, the part name, and the number of elements. The format is as follows:

[0060] #! / user / bin / python

[0061] #-*-coding:UTF-8-*-

[0062] import sys,os,string

[0063] ###parameter define of a mappingfile to boiling

[0064] subroutineDataFile = 'subdat_WJ_pipe.dat' # Define the subroutine data source filename (.dat file).

[0065] mappingInpFileName = 'mapping_mypipe_Mapping_inface_in.inp' # Defines the filename for the fluid waterside boundary.

[0066] partName = 'mypipe' + '-1' # Define the part name

[0067] numOfBeforePartElements = 0 # Defines the number of elements of all parts preceding this part in ABAQUS.

[0068] Step 4. Merge the data source .dat files.

[0069] If there are multiple water jacket boundary files, repeat step 3 until all water jacket boundary files are compiled into a FORTRAN-readable data source dat file.

[0070] Run the edited data source dat file (i.e., run it via FORTRAN) to generate the subroutine data source dat file required by the FORTRAN subroutine.

[0071] The generated subroutine data source dat files are merged into one file to form the final callable data source dat file for the FORTRAN subroutine.

[0072] The format is as follows:

[0073]

[0074]

[0075] Step 5. Edit the subroutine.for file, view the merged data source dat from Step 4, assign the file line number to N (line 11) and the file path to File (line 16), and the FORTRAN subroutine is now complete. The subroutine code is as follows:

[0076]

[0077]

[0078]

[0079] Step 6. Import the calculation .inp file into the Job module (i.e., the ABAQUS Job module), specify the FORTRAN subroutine edited in step 5 under the General tab, and then submit the calculation. The Job module interface is as follows. Figure 2 As shown.

[0080] A water jacket boiling correction system, comprising:

[0081] The modification module is used to modify the water jacket boundary file. It obtains the water jacket boundary file provided by the fluid engineer and adds NU after the unit face number in the water jacket boundary file, that is, F1 is changed to F1NU. This indicates that the heat transfer coefficient is no longer uniform and constant, but is variable in real time based on subroutine calculation.

[0082] The extraction module is used to extract the number of parts and convert the part's own unit number into an ABAQUS internal unit number. The calculation formula is that the internal unit number of a part is equal to the sequence number of its own unit number plus the number of units of all the parts preceding it in ABAQUS.

[0083] Write a module to write data source .dat files, and write FORTRAN-readable data source .dat files based on water jacket boundary files;

[0084] The merge module is used to merge data source .dat files.

[0085] If there are multiple water jacket boundary files, repeat step 3 until all water jacket boundary files are compiled into a FORTRAN-readable data source dat file.

[0086] Run the edited data source dat file to generate the subroutine data source dat file required by the FORTRAN subroutine;

[0087] The generated subroutine data source dat files are merged into one file to form the final callable data source dat file of the FORTRAN subroutine;

[0088] The editing module is used to edit the subroutine.for file, view the merged data source dat in step 4, assign the file line number to N and the file path to File, and the FORTRAN subroutine can be edited.

[0089] The calculation module is used to import the calculation .inp file into the Job module. Under the General tab, specify the FORTRAN subroutine edited in step 5, and then submit the calculation.

[0090] A computer device includes a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the above-described water jacket boiling correction method.

[0091] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the aforementioned water jacket boiling correction method.

[0092] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention, and these will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.

Claims

1. A method for correcting boiling in a water jacket, characterized in that, The water-side wall temperature tw is calculated in real time through a subroutine. When tw exceeds the set temperature, the heat transfer coefficient HTC is corrected based on the temperature difference between the wall temperature and the coolant temperature.

2. The water jacket boiling correction method according to claim 1, characterized in that, The corrected equation is: H=h+(18000-h)*(tw-120) / (180-120), where h is the HTC provided by the CFD simulation and H is the corrected heat transfer coefficient.

3. The water jacket boiling correction method according to claim 1, characterized in that, The set temperature is 120℃.

4. A water jacket boiling correction method according to claim 1, 2, or 3, characterized in that, The correction is implemented through FORTRAN subroutines, and the specific process includes the following steps: Step 1. Modify the water jacket boundary file. Obtain the water jacket boundary file provided by the fluid engineer. Add NU after the unit face number in the water jacket boundary file, that is, change F1 to F1NU. This indicates that the heat transfer coefficient is no longer uniform and constant, but is variable in real time based on subroutine calculation. Step 2. Extract the number of parts and convert the part's own unit number to the ABAQUS internal unit number. The calculation formula is that the internal unit number of a part is equal to the sequence number of its own unit number plus the number of units of all the parts preceding it in ABAQUS. Step 3. Write the data source .dat file. Write a FORTRAN-readable data source .dat file based on the water jacket boundary file. Step 4. Merge the data source .dat files. If there are multiple water jacket boundary files, repeat step 3 until all water jacket boundary files are compiled into a FORTRAN-readable data source dat file. Run the edited data source dat file to generate the subroutine data source dat file required by the FORTRAN subroutine; The generated subroutine data source dat files are merged into one file to form the final callable data source dat file of the FORTRAN subroutine; Step 5. Edit the subroutine.for file, view the merged data source dat from Step 4, assign the number of lines in the file to N and the file path to File, and the FORTRAN subroutine will be edited. Step 6. Import the calculation .inp file into the Job module, specify the FORTRAN subroutine edited in Step 5 under the General tab, and then submit the calculation.

5. The water jacket boiling correction method according to claim 4, characterized in that, In step 1, replace all F1 to F4 with F1NU to F4NU one by one.

6. The water jacket boiling correction method according to claim 4, characterized in that, In step 2, the number of cells for all parts in ABAQUS is extracted using a Python program. Specifically, the CAE model is opened, and the instances are traversed to obtain the number of cells and nodes for all parts.

7. The water jacket boiling correction method according to claim 4, characterized in that, In step 3, the water jacket boundary file is written into a FORTRAN-readable data source dat file using a Python program. The specific process is as follows: Open "Write User Subroutine dat file.py", and define the data source dat file name, fluid water side boundary file name, part name, and element quantity parameter required for FORTRAN subroutine calculation according to the actual situation.

8. A water jacket boiling correction system, characterized in that, include: The modification module is used to modify the water jacket boundary file. It obtains the water jacket boundary file provided by the fluid engineer and adds NU after the unit face number in the water jacket boundary file, that is, F1 is changed to F1NU. This indicates that the heat transfer coefficient is no longer uniform and constant, but is variable in real time based on subroutine calculation. The extraction module is used to extract the number of parts and convert the part's own unit number into an ABAQUS internal unit number. The calculation formula is that the internal unit number of a part is equal to the sequence number of its own unit number plus the number of units of all the parts preceding it in ABAQUS. Write a module to write data source .dat files, and write FORTRAN-readable data source .dat files based on water jacket boundary files; The merge module is used to merge data source .dat files. If there are multiple water jacket boundary files, repeat step 3 until all water jacket boundary files are compiled into a FORTRAN-readable data source dat file. Run the edited data source dat file to generate the subroutine data source dat file required by the FORTRAN subroutine; The generated subroutine data source dat files are merged into one file to form the final callable data source dat file of the FORTRAN subroutine; The editing module is used to edit the subroutine.for file, view the merged data source dat in step 4, assign the file line number to N and the file path to File, and the FORTRAN subroutine can be edited. The calculation module is used to import the calculation .inp file into the Job module. Under the General tab, specify the FORTRAN subroutine edited in step 5, and then submit the calculation.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements a water jacket boiling correction method according to any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements a water jacket boiling correction method according to any one of claims 1-7.

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