Heat of reaction

sara137 · June 15, 2020, 10:38

Hello,
I am trying to model 3D, reacting case. I defined my fluids and their enthalpies also the kinetic model and Arrhenius constants. However the heat of reaction source in the result reports is zero. Does it means that I have exothermic reactions or there is a mistake?
Thank you!

vinerm · June 15, 2020, 10:57

It is calculated using standard state enthalpies provided by the user in the materials panel.

sara137 · June 15, 2020, 11:22

Thank you Vinerm for your reply.
I already defined standard state enthalpies as constant in the material panel, that makes me confused!

vinerm · June 15, 2020, 16:30

Also check for their values. If the sum of the enthalpies, of course along with the moles of the products and reactants, is 0, then heat of reaction would be 0. So, values should be realistic. Try some random values and see if it changes anything. And it would not show up after initialization. Case has to be run, at least for 1 iteration.

June 15, 2020, 10:38	Heat of reaction	#1
sara137 New Member sara Join Date: Jun 2020 Posts: 11 Rep Power: 6	Hello, I am trying to model 3D, reacting case. I defined my fluids and their enthalpies also the kinetic model and Arrhenius constants. However the heat of reaction source in the result reports is zero. Does it means that I have exothermic reactions or there is a mistake? Thank you!

June 15, 2020, 10:57	Heat of Reaction	#2
vinerm Senior Member Vinerm Join Date: Jun 2009 Location: Nederland Posts: 2,946 Blog Entries: 1 Rep Power: 36	It is calculated using standard state enthalpies provided by the user in the materials panel. __________________ Regards, Vinerm PM to be used if and only if you do not want something to be shared publicly. PM is considered to be of the least priority.

June 15, 2020, 16:30	Standard State Enthalpies	#4
vinerm Senior Member Vinerm Join Date: Jun 2009 Location: Nederland Posts: 2,946 Blog Entries: 1 Rep Power: 36	Also check for their values. If the sum of the enthalpies, of course along with the moles of the products and reactants, is 0, then heat of reaction would be 0. So, values should be realistic. Try some random values and see if it changes anything. And it would not show up after initialization. Case has to be run, at least for 1 iteration. __________________ Regards, Vinerm PM to be used if and only if you do not want something to be shared publicly. PM is considered to be of the least priority.

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June 15, 2020, 11:22		#3
sara137 New Member sara Join Date: Jun 2020 Posts: 11 Rep Power: 6	Thank you Vinerm for your reply. I already defined standard state enthalpies as constant in the material panel, that makes me confused!