[AustinK_8]

I'm running a multiphase transient simulation of saturated liquid water flowing through a tube with constant heat flux from one side. I'm using ANSYS 2022 student edition. My required heat flux is 2*10^6 W/m^2 (2 MW/m^2) and the issue is after a very short period of flow time (<0.1 sec) the Courant number suddenly jumps to over 250 and I get a floating point exception error.

I have tried a number of troubleshooting tips - most of which are detailed on the "CFD Setup" slide of the slide deck linked below. The greatest improvement has come from reducing the heat flux by orders of magnitude, but I'm still getting flow times below 1 second before error. Even with heat fluxes as low as 2*10^3 or 2 kW/m^2 it stops at about 1.5 sec.


https://drive.google.com/file/d/14ng...ew?usp=sharing

Thank you in advance for your help!