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-   -   UDF for heat transfer cofficient (https://www.cfd-online.com/Forums/fluent/45062-udf-heat-transfer-cofficient.html)

rosol June 17, 2007 12:17

UDF for heat transfer cofficient
 
Hi

I don't have any idea about using UDF .I need to calculate the distribution of Bulk temperature then the heat transfer cofficeint to calculate the overall heat transfer cofficient of heat exchanger. Please can any one explain the using of UDF and give me the way to calculate the mentioned parameters.

Thanks alot

Jack Martinez June 18, 2007 10:52

Re: UDF for heat transfer cofficient
 
Hello!!

I am also going through same phase. Based on my experience, this is all I can suggest you

1. Use Execute_at_end macro

2. Obtain the temperature at Face and near wall region.

3. Calculate the heat flux (using mear wall approach)... I am informed that there is a predefined macro to extract the heat flux but I couldn't find it out.. if u find anything do pass it on this community ...

4. Use heat flux and the difference of above extracted temperature to calculate the HTC..

All the macros mentioned above are explained in UDF manual.. hope u can find them urself...

Jack ...

romio June 18, 2007 13:11

Re: UDF for heat transfer cofficient
 
Thank you Jack Martinez for your answer Please 1- Can you send me these macros becaouse I don't have suffecient experines about fluent and especially about using the UDF

2- Is the value of heat flux obtained from fluent directly from xy plot in certain surface tru ? and can I use it in my calculations by applying HTC=q/(Tm-Tw)to calculate heat transfer cofficient and then to calculate Nn from Nu=HTC*Dh/k.

Regards

rosol June 19, 2007 08:06

Re: UDF for heat transfer cofficient
 
Thank you very much Jack


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