Simulation of Multiphase Heat Exchanger

faisal_ahmed92 · June 8, 2012, 14:54

Hello all, I've been using Cfx 13 to simulate a heat exchanger simulation, with water flowing through outer chamber taking heat from inner coil, through which acetone flows. Due to heat given to water acetone condenses
My approach to solving:
Define two separate domains, water and acetone zone, and then in the domain interface define a heat exchange with copper of 1mm thickness. Problem is my solver keeps crashing after 3 or 4 iterations with
Floating Point Error : Overflow,
The one time I got a complete run, the CFD post doesn't show any streamlines for the coil domain. Please help, Ive been at it for weeks now!!

faisal_ahmed92 · June 10, 2012, 11:12

Anybody PLEASSE!! Ive been stuck on this a very long time!!

ghorrocks · June 11, 2012, 21:14

http://www.cfd-online.com/Wiki/Ansys...do_about_it.3F

faisal_ahmed92 · June 12, 2012, 04:06

Just wanted to say that you are legend over here!!. Many thanks, I tried using those steps and got a solution, but the problem is the solver doesn't solve for the inner(coil) domain at all. I looked up the condensation tutorial, but that has a mixed gas phase and a liquid phase, whereas i am looking for a gas and a liquid phase in one single domain(coil). Any thoughts?

ghorrocks · June 12, 2012, 20:44

I would do some development work with the inner domain only. Run that as a model by itself and see what settings it likes to converge. Then combine that with the full simulation.

faisal_ahmed92 · June 13, 2012, 04:22

I tried doing that for single phase fluids and it worked WITH the outer domain as well, but when I switch to a condensation model (Acetone vapor continous phase and acetone liquid dispersed fluid), the solver just doesnt solve for the inner domain

ghorrocks · June 13, 2012, 08:33

Condensation models are tricky multiphase models - so replace the outer domain with a constant temperature wall and work on getting condensation working in that simpler case before coupling it together.

June 8, 2012, 14:54	Simulation of Multiphase Heat Exchanger	#1
faisal_ahmed92 New Member Faisal Join Date: Jun 2012 Posts: 5 Rep Power: 14	Hello all, I've been using Cfx 13 to simulate a heat exchanger simulation, with water flowing through outer chamber taking heat from inner coil, through which acetone flows. Due to heat given to water acetone condenses My approach to solving: Define two separate domains, water and acetone zone, and then in the domain interface define a heat exchange with copper of 1mm thickness. Problem is my solver keeps crashing after 3 or 4 iterations with Floating Point Error : Overflow, The one time I got a complete run, the CFD post doesn't show any streamlines for the coil domain. Please help, Ive been at it for weeks now!!

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June 10, 2012, 11:12		#2
faisal_ahmed92 New Member Faisal Join Date: Jun 2012 Posts: 5 Rep Power: 14	Anybody PLEASSE!! Ive been stuck on this a very long time!!

June 11, 2012, 21:14		#3
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	http://www.cfd-online.com/Wiki/Ansys...do_about_it.3F

June 12, 2012, 04:06		#4
faisal_ahmed92 New Member Faisal Join Date: Jun 2012 Posts: 5 Rep Power: 14	Just wanted to say that you are legend over here!!. Many thanks, I tried using those steps and got a solution, but the problem is the solver doesn't solve for the inner(coil) domain at all. I looked up the condensation tutorial, but that has a mixed gas phase and a liquid phase, whereas i am looking for a gas and a liquid phase in one single domain(coil). Any thoughts?

June 12, 2012, 20:44		#5
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	I would do some development work with the inner domain only. Run that as a model by itself and see what settings it likes to converge. Then combine that with the full simulation.

June 13, 2012, 04:22		#6
faisal_ahmed92 New Member Faisal Join Date: Jun 2012 Posts: 5 Rep Power: 14	I tried doing that for single phase fluids and it worked WITH the outer domain as well, but when I switch to a condensation model (Acetone vapor continous phase and acetone liquid dispersed fluid), the solver just doesnt solve for the inner domain

June 13, 2012, 08:33		#7
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	Condensation models are tricky multiphase models - so replace the outer domain with a constant temperature wall and work on getting condensation working in that simpler case before coupling it together.