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-   -   heat exchanger model (http://www.cfd-online.com/Forums/fluent/48848-heat-exchanger-model.html)

jack July 23, 2008 04:43

heat exchanger model
 
What does exactly means the following error: NTU value not converged after 50 iterations. I am getting these message after I tried to apply the heat exchanger model data for my heat exchanger. I am using NTU model with fixed heat rejection. Thnak u for the help

umesh javiya July 23, 2008 13:59

Re: heat exchanger model
 
Internally fluent solve iteratively non-linear relation for NTU for only 50 iterations using initial guess of inlet temperature which is given in heat exchanger panel and it is not converging within this 50 iterations... you can try diferent thing like 1) guess different value of inlet temperature (increase or decrease by 50C) ... 2) ignore this error and continue ur simulations... when flow is converging then this problem may disappear, provided that you have given all data and boundary condition physically right. 3) If none of this work then give zero coolant flow rate data column. means give data for when coolant flow rate is zero. At zero coolant flow rate heat transfer rate will be zero for all value of primary flow rate. like as follow...this will definetly works... This is not a good idea cause the in simulation calculated temperature is out of the range of data input in heat exchanger panel. so try to provide as much as data possible.

coolant flow (kg/s): 0 kg/s

primary flow(kg/s): 0 0.1 0.2 0.3 0.4 0.5 (as per your data) heat transfer(w): 0 0 0 0 0 0


J.SURESHKUMAR July 24, 2008 08:26

Re: heat exchanger model
 
Respected sir,

since i am doing my final year poject in heat exchanger model using fluent software..i need some tutorials so please help for the same

jack July 25, 2008 04:26

Re: heat exchanger model
 
Hi umesh javiya. Thank you for ur answer. After trying ur advice , I actually figured out a big mistake. I forgot to divided by 2 my value of heat rejection cuz I am using a symetry. Sorry for that but thanks for tips


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