Floating Point Exception in reaction channel

idil · December 19, 2012, 05:56

Hello, I'am trying to simulate a highly exothermic reaction mechanism in a microchannel reactor. Solution Initialization gives an error: foating point exception. And I can't proceed to iterations. Is it about the solver parameters or my initial conditions? Anyone can help?

RodriguezFatz · December 19, 2012, 07:55

Hey,
In 100% of the cases this happened to me is was due to a mesh error (negative volume / faces error...). Did you check your mesh?

idil · December 19, 2012, 08:00

yes I checked the mesh, no negative value for volume or face area. mesh seems normal. Also I checked my rxn and diffusivity udf's they're normal too. What could be the cause of this problem?

RodriguezFatz · December 19, 2012, 08:03

Why don't you start a new project and load the mesh. Maybe set some simple BCs.
Now try to initialize. If this works then switch on all "extras", but one by one. Try to initialize each time.

idil · December 19, 2012, 08:33

Actually I assigned the BC's in gambit (velocity in-, pressure out, interface etc.) then read the mesh in fluent and I put initial values to speicific boundries ( superficial velocity etc) in fluent. Is it OK to assign the BC's in Fluent? because it is hard to identify default names fluent gives to different boundaries. by the way I have 2D geometry and 4 different layers in my system (up-to down: coolant-wall-catalyst-channel)

RodriguezFatz · December 19, 2012, 11:09

I am sorry, I allways set the BCs in fluent...

December 19, 2012, 05:56	Floating Point Exception in reaction channel	#1
idil New Member idil tezcan Join Date: Oct 2012 Posts: 13 Rep Power: 14	Hello, I'am trying to simulate a highly exothermic reaction mechanism in a microchannel reactor. Solution Initialization gives an error: foating point exception. And I can't proceed to iterations. Is it about the solver parameters or my initial conditions? Anyone can help?

December 19, 2012, 07:55		#2
RodriguezFatz Senior Member Philipp Join Date: Jun 2011 Location: Germany Posts: 1,297 Rep Power: 27	Hey, In 100% of the cases this happened to me is was due to a mesh error (negative volume / faces error...). Did you check your mesh? __________________ The skeleton ran out of shampoo in the shower.

December 19, 2012, 08:03		#4
RodriguezFatz Senior Member Philipp Join Date: Jun 2011 Location: Germany Posts: 1,297 Rep Power: 27	Why don't you start a new project and load the mesh. Maybe set some simple BCs. Now try to initialize. If this works then switch on all "extras", but one by one. Try to initialize each time. __________________ The skeleton ran out of shampoo in the shower.

December 19, 2012, 11:09		#6
RodriguezFatz Senior Member Philipp Join Date: Jun 2011 Location: Germany Posts: 1,297 Rep Power: 27	I am sorry, I allways set the BCs in fluent... __________________ The skeleton ran out of shampoo in the shower.

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December 19, 2012, 08:00		#3
idil New Member idil tezcan Join Date: Oct 2012 Posts: 13 Rep Power: 14	yes I checked the mesh, no negative value for volume or face area. mesh seems normal. Also I checked my rxn and diffusivity udf's they're normal too. What could be the cause of this problem?

December 19, 2012, 08:33		#5
idil New Member idil tezcan Join Date: Oct 2012 Posts: 13 Rep Power: 14	Actually I assigned the BC's in gambit (velocity in-, pressure out, interface etc.) then read the mesh in fluent and I put initial values to speicific boundries ( superficial velocity etc) in fluent. Is it OK to assign the BC's in Fluent? because it is hard to identify default names fluent gives to different boundaries. by the way I have 2D geometry and 4 different layers in my system (up-to down: coolant-wall-catalyst-channel)