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July 21, 2021 at 3:08 pm
Georf
Subscriber
Hello,
Thank you for your help so far Karthik. As you have mentioned the solution must be converged in every time-step. This does not happen to my case, so in order to achieve that do you believe it is a good idea to run my simulation as steady time until it converges and then as a transient simulation?
My project is the simulation of a shell and tube heat exchanger with a parrafin. As you can see in picture 1, I have 7 tubes with water flowing inside them, and these tubes are covered from the paraffin. The aim of the simulation is to lower water's temperature and melt the parrafin. I have created the pcm as fluid, the tubes as solid and in addition the water as fluid. In picture 2, you can see the mesh setup I used.As you can see I used linear element order and the default size which may be too small given that the paraffin is 1.2 meters long and has a radius of 1 meter but the tubes have outer diameter of 25.4mm and inner diameter of 20mm. In picture 3, 4, 5 you can see the boundary conditions that I have used. For the water inlet, I use velocity inlet with a velocity of 0.12m/s and a temperature of 40 Celsius. My outlets are modelled as outflows. I have also a symmetry plane. As for the other boundary conditions I have considered the surfaces as walls and I have added a conduction layer in order to have natural convection at the contact of the solid with the fluid. The residuals I have kept them to their default settings. The UDF the same. I have the gravity activated.
At the initialization phase, I choose the whole model to be at 5 Celsius and then I patch the water at 40 Celsius.
I hope this description is helpful. Feel free to make any suggestions you want. I look forward to your answer.
Thank you for your help so far Karthik. As you have mentioned the solution must be converged in every time-step. This does not happen to my case, so in order to achieve that do you believe it is a good idea to run my simulation as steady time until it converges and then as a transient simulation?
My project is the simulation of a shell and tube heat exchanger with a parrafin. As you can see in picture 1, I have 7 tubes with water flowing inside them, and these tubes are covered from the paraffin. The aim of the simulation is to lower water's temperature and melt the parrafin. I have created the pcm as fluid, the tubes as solid and in addition the water as fluid. In picture 2, you can see the mesh setup I used.As you can see I used linear element order and the default size which may be too small given that the paraffin is 1.2 meters long and has a radius of 1 meter but the tubes have outer diameter of 25.4mm and inner diameter of 20mm. In picture 3, 4, 5 you can see the boundary conditions that I have used. For the water inlet, I use velocity inlet with a velocity of 0.12m/s and a temperature of 40 Celsius. My outlets are modelled as outflows. I have also a symmetry plane. As for the other boundary conditions I have considered the surfaces as walls and I have added a conduction layer in order to have natural convection at the contact of the solid with the fluid. The residuals I have kept them to their default settings. The UDF the same. I have the gravity activated.
At the initialization phase, I choose the whole model to be at 5 Celsius and then I patch the water at 40 Celsius.
I hope this description is helpful. Feel free to make any suggestions you want. I look forward to your answer.
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