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-   -   heat realease in wall by surface reaction (FLUENT) (http://www.cfd-online.com/Forums/main/11025-heat-realease-wall-surface-reaction-fluent.html)

 Marie-Anne March 17, 2006 17:32

heat realease in wall by surface reaction (FLUENT)

Hi,

I am confused about which boundary conditions to choose for the wall where a surface reaction that releases heat takes place. If I choose constant temperature, then the fact that the wall should be heated is lost. If I choose zero heat flux, then it heats too much because it is considered as adiabatic. Thanks for any advice or previous experience on that.

Marie-Anne

 Andrew Hayes March 17, 2006 17:47

Re: heat realease in wall by surface reaction (FLU

I believe that would be a constant heat flux bc, as long as your reaction is exothermic. You have to know the heating value of the reaction

 Marie Anne March 18, 2006 01:36

Re: heat realease in wall by surface reaction (FLU

Thanks Andrew but I believe that knowing the enthalpy of formation, fluent computes itself the heat produced by the reaction. I just dont know where this heat goes and how to tell Fluent it heats the wall.

Thank you :)

Marie Anne

 Andrew Mettler Hayes March 18, 2006 07:59

Re: heat realease in wall by surface reaction (FLU

when you set up the boundary condition for the wall you can set it up as a constant heat flux. you just have to know how much heat is being released. Though, I have never done any reaction stuff. When I do a constant heat flux in fluent I set up a surface in Gambit that I can define as a 'constant heat flux' in Fluent - sort of hard to explain via the net.

 RoM March 20, 2006 10:15

Re: heat realease in wall by surface reaction (FLU

Another option is to use the convection bc with a high htc (>1000). In this case the free stream temperature is almost equal to the outer wall temperature of your domain. This approach is good if you have already measured vaules for outer wall temperature.

RoM

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