Combustion over water Help!!!!

njw · November 12, 2011, 13:20

Hi there,

I am relatively new to Ansys and CFD in general and am having big problems with setting up a transient methane-oxygen combustion system over a free surface of liquid water on CFX.

I am trying to model both the liquid and gas phases and couple the two to determine evaporation rates and convection cells in both phases.
To start off I only have a simple 2D channel with free-slip walls everywhere except an opening at the end. I know its inaccurate but for the sake of computation time I am using the eddy dissipation and k-e models for combustion and turbulence respectively.

The system works without any ignition source present; the combustible atmosphere exists above the liquid surface. However, when I try to introduce a point energy source to ignite the mixture, the solver crashes on the first iteration loop every time.

Advice would be greatly appreciated!
Thanks

ghorrocks · November 13, 2011, 16:58

Does the free surface move? Have waves? Splashes, foam, bubble entrapment or anything like that?

November 12, 2011, 13:20	Combustion over water Help!!!!	#1
njw New Member Neal Wannell Join Date: Nov 2011 Posts: 5 Rep Power: 14	Hi there, I am relatively new to Ansys and CFD in general and am having big problems with setting up a transient methane-oxygen combustion system over a free surface of liquid water on CFX. I am trying to model both the liquid and gas phases and couple the two to determine evaporation rates and convection cells in both phases. To start off I only have a simple 2D channel with free-slip walls everywhere except an opening at the end. I know its inaccurate but for the sake of computation time I am using the eddy dissipation and k-e models for combustion and turbulence respectively. The system works without any ignition source present; the combustible atmosphere exists above the liquid surface. However, when I try to introduce a point energy source to ignite the mixture, the solver crashes on the first iteration loop every time. Advice would be greatly appreciated! Thanks

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
mass flow in is not equal to mass flow out	saii	CFX	12	March 19, 2018 05:21
Water subcooled boiling	Attesz	CFX	7	January 5, 2013 03:32
Combustion with water cooling	Hlynur Thorkelsson	FLUENT	2	March 21, 2007 14:13
Terrible Mistake In Fluid Dynamics History	Abhi	Main CFD Forum	12	July 8, 2002 09:11
uptodate water distribution network	fredius,magige,tanzanian,(e.a)	Main CFD Forum	0	January 27, 2002 07:10

November 13, 2011, 16:58		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	Does the free surface move? Have waves? Splashes, foam, bubble entrapment or anything like that?