Conjugate heat transfer Problem for Triple Pipe Heat Exchanger

KapilO8 · May 9, 2018, 09:19

Hi Everyone!

I'm a new user of Converge Studio and have been learning it for the past few weeks. To get over the edge, i tried to simulate a triple pipe heat exchanger in converge, for which we did have experimental results performed in the laboratory.

To my best knowledge I have set the regions and boundary conditions properly. However, when i try to run the problem, i notice the following:

1. The results are very much different. the inlet temperature of hot water is 75deg C. and the Outlet temperature was 62deg C in the results, which was 45deg C experimentally.

2. The output files creation stopped after some time whereas the solver kept running for long without generation of output files.

Noticing this, i had to stop the simulation in between. I'm afraid that I may have messed with simulation parameters such as CFL numbers..

I'm also attaching the .cvg & log file for better information: https://drive.google.com/open?id=1Rw...GL2vhS035EsA33

xieshengbai · May 9, 2018, 19:30

Hi,

Let me try to answer your questions:

1. The results are very much different. the inlet temperature of hot water is 75deg C. and the Outlet temperature was 62deg C in the results, which was 45deg C experimentally.

It is really hard to tell why your results don't match the experimental data without looking at the case setup. However, in order to do so, you have to contact support@convergecfd.com to submit a formal inquiry.

2. The output files creation stopped after some time whereas the solver kept running for long without generation of output files.

Please check the time step (dt) to see if it becomes very small as a result of "recovery" of some sort. The recovery simply indicates that the solver has not converged properly. When a recovery occurs and repeats, the solver would go back to the last time step, reduce dt by half and redo the loop. It is possible that the time marching might be stuck if the recovery persists. So, you have to figure out what causes the recovery and solve it.

May 9, 2018, 09:19	Conjugate heat transfer Problem for Triple Pipe Heat Exchanger	#1
KapilO8 New Member Kapil Join Date: Apr 2018 Location: India Posts: 16 Rep Power: 8	Hi Everyone! I'm a new user of Converge Studio and have been learning it for the past few weeks. To get over the edge, i tried to simulate a triple pipe heat exchanger in converge, for which we did have experimental results performed in the laboratory. To my best knowledge I have set the regions and boundary conditions properly. However, when i try to run the problem, i notice the following: 1. The results are very much different. the inlet temperature of hot water is 75deg C. and the Outlet temperature was 62deg C in the results, which was 45deg C experimentally. 2. The output files creation stopped after some time whereas the solver kept running for long without generation of output files. Noticing this, i had to stop the simulation in between. I'm afraid that I may have messed with simulation parameters such as CFL numbers.. I'm also attaching the .cvg & log file for better information: https://drive.google.com/open?id=1Rw...GL2vhS035EsA33

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May 9, 2018, 19:30		#2
xieshengbai Member Shengbai Xie Join Date: Aug 2016 Location: Convergent Science, Madison WI Posts: 68 Rep Power: 10	Hi, Let me try to answer your questions: 1. The results are very much different. the inlet temperature of hot water is 75deg C. and the Outlet temperature was 62deg C in the results, which was 45deg C experimentally. It is really hard to tell why your results don't match the experimental data without looking at the case setup. However, in order to do so, you have to contact support@convergecfd.com to submit a formal inquiry. 2. The output files creation stopped after some time whereas the solver kept running for long without generation of output files. Please check the time step (dt) to see if it becomes very small as a result of "recovery" of some sort. The recovery simply indicates that the solver has not converged properly. When a recovery occurs and repeats, the solver would go back to the last time step, reduce dt by half and redo the loop. It is possible that the time marching might be stuck if the recovery persists. So, you have to figure out what causes the recovery and solve it.