[mwaqas]

Hello everyone,


I am using OF5x and Ubuntu 17.10.
I am simulation 2D transient heat transfer between solid and fluid using PIMPLE algorithm. I am using chtMultiRegionHeater tutorial as base case.

Initially, the temperature of fluid (liquid) is 30 degree less than the solid (figure 1, Blue part is liquid, red is solid). I used constant density thermo-physaical model.

I have run my simulation for more than 95 sec. After 95 sec, the decrease in solid temperature is very less (figure 2), approx. 2K. Same model has been used in Ansys-fluent and more than 10K drop is temperature has been observed. Experimental results also confirm the Ansys results. I tried many things but unable to identify the reason for this slow temperature gradient.
Initially, I used nOuterCorrectors = 300 and than gradually decreased after 5sec to 30 iterations. Whie after 5 sec, it didn't take long o converge in each time step. I have attached my Initial and Boundary conditions file for fluid and solid as well as fvSchemes and fvSolutions for fluid.
Apparently, it is looking like that no heat is transferring across boundary.
nOuterCorrectors has been controlled through system/fvSolutions

Please give me some suggestions, where I am making mistake.

Thank you




PS: I cannot show my entire domain.



Regards

[mwaqas]

Here is my mesh and for solid regions. Fluid region has uniform mesh size.

[mwaqas]

My problem has been resolved. I was making a silly mistake. I was using kinematic viscosity (KV) in thermo-physical properties. Due to very small value of KV, there was a very slow heat transfer between fluid and solid which was not visible. After changing the KV to dynamic viscosity, everything is working fine.