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Thermal transfert diffusion and convection

MP6513
Participant

Thermal transfert diffusion and convection

Hello,

 

I have a problem : I want to analyse the thermal heat evolution of a wall with fluid heat variation. Can you help me ?

 

Thank you.

 

Michel

6 REPLIES 6

Re: Thermal transfert diffusion and convection

You have two constraints for Phi_d(x,t):

With 'Flux' it is equal to:     -a * Temp.x(x,t)                    which may be a function of t AND x
With 'Cond. aux limites':    Phi_h_S(t)-Phi_h_P(t),        which is a function of t, not of x.

If I define:

LucMeekes_0-1592588558549.png

I can:

LucMeekes_1-1592588600096.png

Then the solve block becomes:

LucMeekes_3-1592588709353.png

So you have two different constraints for Phi_d(x,t), but you could also state:

LucMeekes_4-1592588825720.png

Which leaves Phi_d.x(x,t) undefined, and that might explain why I get an 'undefined variable or function' error message.

If you could set initial conditions for Phi_d(x,t), you might be able to solve for Temp and Phi_d simultaneously.

 

Success!
Luc

 

 

Re: Thermal transfert diffusion and convection

Hi,

In order not to confuse and not to waste time in the interpretation of your file, you should provide us with the text and the equations to be used in Mathcad, including the initial and boundary conditions.

Re: Thermal transfert diffusion and convection

The topic interests me, however thanks anyway.

Re: Thermal transfert diffusion and convection

I publish something about the cooling. I don't know if you are interested:

cooling 0.jpgcooling 1.jpgcooling 2.jpg

Re: Thermal transfert diffusion and convection

How about the attached?

You have weird boundary conditions though:  one end varies from -10 to +10, the other from -300 to + 300.

 

g0.jpg

 

Alan

Re: Thermal transfert diffusion and convection

I am very interested in all yours responses. Thank you very much for spending time helping me for this problem. The data being confidential, I had simplified the functions, which could have made the subject less comprehensible to you. The thermal exchange and boundary condition functions are described with very severe transients. now I will put in practice your precious advice.

 

Thank you all.

 

Michel

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