Respected Sirs,
I am trying to simulate heat transfer coefficient of super-critical water in fluent. Geometry is simple tube with constant heat flux applied at wall operating at 24.52 M Pa. I used the manual input of properties giving 50 points to fluent and the results were reasonable but it didn't covered the whole range of properties due to limitation of 50 points only so i moved towards the NIST real gas model with "water.fld" file and the results got flattered. The reason might be the wrong boundary conditions as i used mass flux inlet with 24.52 M Pa and pressure outlet with same pressure.
Can anyone help me to resolve my problem that how to use this model more efficiently and accurately?
Thanks a lot.
Best Regards
M Kashif Tehseen
Thanks a lot Mr. Xinyou Ke for your response. I am keeping the pressure constant as the pressure drop in my case is negligibly small.
The reason is not the same pressure at the inlet and at the outlet.
"got flattered" means divergence？When you can not get the converged results by using the NIST model, initial the value by "all zone" in the initial panel and decrease the relax factors. Further more, use SIMPC method. Correct the "limits" of pressure and temperature for your calculation in the solution controls panel: solution controls-limits. NIST model supply the properties with limited temperature and pressures.
Thanks a lot Mr. Houjian Zhao for your valued information. By flattered i mean randomness or increased error of results not the divergence. I always get the converged solution with defaults relaxation factors.
Please let me know what should I do in this case.
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