Enthalpy Diffusion Testcase

gregor · September 7, 2013, 07:15

Hi guys,

i am currently compiling a set of test cases to see if my solver derived from reactingFoam 2.0.x conserves specific properties. One test case that worries me a bit is the diffusion of a temperature profile. With all source terms switched off in the sensible enthalpy equation i am looking at the mean enthalpy of the gas in my domain. However with all tested solvers it seems that the enthalpy decreases over time. Maybe its just a boundary or set up problem or something that i am overlooking.

You can find the relevant files at:

https://github.com/greole/ValidationCases

Thanks alot

Gregor

adhiraj · September 8, 2013, 01:14

Do you account for enthakpy diffusion?
Try running the solver with Le=1. and see if that helps.

gregor · September 8, 2013, 09:46

Hi Adhiraj,

thx for your reply. I am running the test case with the reactingFoam solver which accounts for enthalpy diffusion. Le=1 didn't change anything (I use Y_N2=1 everywhere, anyway). What i find interesting is that if i solve for a passive scalar the mean value is conserved. Can someone confirm the behaviour of missing enthalpy or sees any problem with the test case ?

Gregor

September 7, 2013, 07:15	Enthalpy Diffusion Testcase	#1
gregor Member Gregor Olenik Join Date: Jun 2009 Location: http://greole.github.io/ Posts: 89 Rep Power: 16	Hi guys, i am currently compiling a set of test cases to see if my solver derived from reactingFoam 2.0.x conserves specific properties. One test case that worries me a bit is the diffusion of a temperature profile. With all source terms switched off in the sensible enthalpy equation i am looking at the mean enthalpy of the gas in my domain. However with all tested solvers it seems that the enthalpy decreases over time. Maybe its just a boundary or set up problem or something that i am overlooking. You can find the relevant files at: https://github.com/greole/ValidationCases Thanks alot Gregor

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September 8, 2013, 01:14		#2
adhiraj Senior Member Adhiraj Join Date: Sep 2010 Location: Karnataka, India Posts: 187 Rep Power: 15	Do you account for enthakpy diffusion? Try running the solver with Le=1. and see if that helps.

September 8, 2013, 09:46		#3
gregor Member Gregor Olenik Join Date: Jun 2009 Location: http://greole.github.io/ Posts: 89 Rep Power: 16	Hi Adhiraj, thx for your reply. I am running the test case with the reactingFoam solver which accounts for enthalpy diffusion. Le=1 didn't change anything (I use Y_N2=1 everywhere, anyway). What i find interesting is that if i solve for a passive scalar the mean value is conserved. Can someone confirm the behaviour of missing enthalpy or sees any problem with the test case ? Gregor