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-   -   steady state evaluation! (http://www.cfd-online.com/Forums/cfx/63817-steady-state-evaluation.html)

princeps11 April 21, 2009 02:18

steady state evaluation!
 
Dear memebrs;

I always appreciate your valuable comments and ideas.

Now I try to simulate heating panel embedded water pipe.

except one surface, all faces are adiabatic conditions.

at the surface, heating load is placed on the boundary(about -500W)

water is supplied at 35C.

From the first law, water outlet temperature will be around 25C when the water mass flow is set at 0.0138 kg/s.

I want to know the surface temperature and water outlet temperature thourgh S/S condition in CFX.

If the panel set 15C then water is start to circulate, should I set the initial condition of the panel(solid) at 15C or expected temperature (around 27C)? I mean the panel surface temperature will be around 27C (I expected) after water is fully circulated.

What is a suitable option for time scale control? (autotime scale or physical time scale factor)

Whenever I changed the time scale control (Auto -aggressive, conservative) and initial condition of solid and fluid(water), output is very different. I'm not sure what is reasonable data.

please let me know the best shot!

regards!

rikio April 21, 2009 04:18

Hi,

The temperature of the surface will reach a balanced one once your steady state solution converged. So just set a heat flux for this surface since -500W is given.
Regarding the timescale, just follow the Advice on Flow Modelling on Timestep Selection. Do all of the models of different timescale settings have converged ? If not, it is normal to differ greatly.


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