Conjugate heat transfer problem
Posted: 01 Apr 2019, 20:50
Hi,
I'm doing a coupled heat fluid flow simulation with a fluid channel flowing through a solid with a heat load on it's surface (liquid cooled heat-sink), the only path for the heat is into the fluid.
My solution conserves fluid flow, the heat flux into the surface agrees with my Heat Flux boundary condition but the heat energy isn't conserved, i.e. the difference between the integrals of V.rho.c.T over the inlet and outlet is significantly higher (up to 20%) than the heat load?
Does this suggest that my fluid mesh at the no-slip boundary is not good enough? The error does decrease if I make it finer but I only have the option of tetrahedral or prism elements (I only have GMSH for meshing). With a "fine" mesh using 8 cores my solution time with linear elements is >8hrs and increasing the order to quadratic would be prohibitive and would exceed my available memory ;-(
My tolerance settings in both the Navier-Stokes and the Heat equation are already very tight.
The Reynolds number for the flow is ~1000
Are there any settings that would reduce the energy imbalance error?
Any suggestions?
Thanks in advance, Regards
Mark
I'm doing a coupled heat fluid flow simulation with a fluid channel flowing through a solid with a heat load on it's surface (liquid cooled heat-sink), the only path for the heat is into the fluid.
My solution conserves fluid flow, the heat flux into the surface agrees with my Heat Flux boundary condition but the heat energy isn't conserved, i.e. the difference between the integrals of V.rho.c.T over the inlet and outlet is significantly higher (up to 20%) than the heat load?
Does this suggest that my fluid mesh at the no-slip boundary is not good enough? The error does decrease if I make it finer but I only have the option of tetrahedral or prism elements (I only have GMSH for meshing). With a "fine" mesh using 8 cores my solution time with linear elements is >8hrs and increasing the order to quadratic would be prohibitive and would exceed my available memory ;-(
My tolerance settings in both the Navier-Stokes and the Heat equation are already very tight.
The Reynolds number for the flow is ~1000
Are there any settings that would reduce the energy imbalance error?
Any suggestions?
Thanks in advance, Regards
Mark