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Eugene January 14, 2002 05:18

Heat transfer coefficient
Hello! I'm student and have some problem... Can somebody help me: were I can find some information how calculate heat transfer coefficient from cfd data: (1) when I use wall function and boundary gradients (2) may be another methods? My problem is heat sink for cooling semiconductor elements with force convection.

Paul Ramshaw January 14, 2002 06:07

Re: Heat transfer coefficient
Dear Eugene,

Flotherm is the market leading CFD thermal modelling software used in the electronics industry worldwide. Please refer to for more information.

Michael Malin January 14, 2002 06:58

Re: Heat transfer coefficient
The wall-function formulae employ a local Stanton number St from which the local heat transfer coefficient (htc) can be determined from St*density*relative velocity*specific heat. The formula for St depends on the actual empirical correlation used. For an example see ). Commericial codes usually make provision for the output of the htc, but if you are using a research code you will have to calculate it yourself.

Eugene January 14, 2002 10:01

Re: Heat transfer coefficient
Hello! Can you advice me how to calculate Heat transfer coefficient from Phoenics. I have STAN and SKIN for wall function 'log-law' and KE-EP turbulence model. My case is air flow in channel. For boundary cell I have: (1) Alfa1=Ro(air)*U1*Cp(air)*STAN were U1-fist point in air. (2) Nu(real)=STAN*(Tw-T1)/(Tw-T(overal))*U1/U(overall)*Re*Pr were U(overall)=Integral(Udx)/Integral(dx) T(overall)=Integral(U*T*dx)/Integral(U*dx) (3) Alfa(real)/Alfa(1)=(Tw-T1)/(Tw-T(overall))

But this algoritm is not working in conner area. And STAN have have strange profile ->1/Alfa1... Why?

Michael Malin January 14, 2002 12:48

Re: Heat transfer coefficient
STORE(HTCO) should elicit storage and printout of the heat transfer coefficient.

I suspect that the printed corner Stanton number refers to one of the corner faces (whichever was calculated last) and is not a weighted average of the two corner faces.

I don't understand what is meant by: "And STAN have have strange profile ->1/Alfa1...". Provide a more detailed and precise explanation.

I suggest that you submit PHOENICS questions to the PHOENICS Discussion Group rather than the Main one.

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