Week 6: Conjugate Heat Transfer Simulation
Hello,
In this conjugate heat transfer challenge, as per the given problem statements, first we find the respective parameters to set our case setup accordingly and plan the simulation. To do the same, first go for importing the geometry, and in this we go for geometry build-up using two concentric cylinders in the CONVERGE-STUDIO. After this, go for the normal checks, which must be pointed in the direction of the flow. Then, a diagnosis is done to check for any kind of geometrical error. After verifying it, the case setup is set as per the given inputs and boundary conditions. In this case, all the basic parameters are selected with specific values, and all these values are setup together as input files for the model. During the case setup, the important thing that we need to keep in mind is that the inner wall of the cylinder is an interface wall, which means that that wall is bounded by solid and fluid on both sides. And during boundary selection, the forward direction is given to the fluid side and the reverse to the solid side because the normal direction is on the side of fluid flow. Instead of meshing the huge outer surface to transfer boundary heat at the outer wall, we go for its alternative—just by providing a heat flux of 10,000 units with a negative sign. A negative sign represents that the heat is going into the geometry and not releasing out. So, after setting that all up, we need to do case setup validation and then export the input files into the folder.
The simulation that follows can be converging by using the Cygwin interface, which is required for giving the command to the software. In Cygwin, first we go to the directory where the input files are present and then command them for simulation. This simulation can be done automatically at the back end, and the output files are generated in the same folder as the results of the simulation.
Then those output files have to be exported in Paraview to see the results in the different interfaces and also in their plots in the Converge Studio. For importing the output files in Paraview, first we need to convert the data into a ".vtm file," which is done in the "Post-Processing 3-D" option in Converge-Studio. Then all the 3D and 2-D analyses of the results are analysed separately. The rest of the plots can be seen in Converge-studio itself, specifically under the "line-plotting option."
By doing so, I was able to obtain all of the required results for this particular challenge and take screenshots of them. The CFD analysis of this problem is done three times for three different mesh sizes, and the results are attached in a word file. Kindly find it below.
Detailed explanations about the plots:
The cell count in this challenge is constant from the beginning to the end because there is no adaptive mesh refinement that we are using that would fluctuate the number of cells throughout the simulation process.
The mass flow rate plots appear to be unstable at first touch, but as the flow cycled on, convergence took effect. After achieving the convergence shown in the graph, we observe that the mass of the flow that enters the geometry from the inlet per unit of time is equal to the mass of the flow that exits from the outlet. But due to the sign conventions, the input and output flows are represented, respectively, as positive and negative values for comparison.
Animation Link:https://youtu.be/7COLh2HXJHk
Anubhav