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-   -   Natural / free convection over vertical plate (http://www.cfd-online.com/Forums/fluent/122519-natural-free-convection-over-vertical-plate.html)

allendoss79 August 21, 2013 08:38

Natural / free convection over vertical plate
 
5 Attachment(s)
Hello everyone,

My problem is to determine the velocity and temperature profile for free convection over a vertical plate for varying properties of the fluid for constant heat flux.
I have accounted for the variation, in the form of a quadratic equation using properties from the website below:

http://webbook.nist.gov/cgi/fluid.cg...m&RefState=DEF

Domain:0.15m*0.04m
Presure based solver,Steady state.Energy and LAMINAR equation turned on

Boundary conditions:
INLET:Gauge pressure=7500000 Pa
Backflow temperature=298 K
OUTLET:Gauge pressure=7500000 Pa
Backflow temperature= 298 K
PLATE:constant heat flux=1000 W/m2
Far end opposite to plate:Symmetry

I have attached the rest of them.
Attachment 24657

Attachment 24658

Attachment 24659

Attachment 24660

Attachment 24661

Questions:
1.Is this the right way of inputting properties in fluent?
2.Wall temperature should be in range 298-302.But in mine varies between 306-313.
3.If gauge pressure is 75bar at inlet and outlet, should the operating pressure be "0 Pa"?
4.Solution hasn't converged yet.It so happens that when i select compute from all zones in the initialization menu fluent changes the initial pressure to half of 75bar and initializes it, but my solution converges at some iteration.Basically a value below 75bar yields(i have tried 74bar) yields some convergence.Why is this so?

Can someone please have a look at it and help?:(


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