Learning Forum

[ll00023]

a previous thread discuss the dimension of heat-of-reaction.

https://innovationspace.ansys.com/forum/forums/topic/dimension-of-heat-of-reaction/

see the dimension of Rj/Mj is (mass/volume)/(mass/volume), hj - J/kg, right? 

Sh's dimension is J/kg. 

in the previous thread, you said, watt is originated from the solver's perspective.  I don't understand this.

for a local view, it should be a volumetric result, even for a node. the node value could represent a local volumetric value in reality, right?

another thing you mention is: even though the unit is watt, it actually represents W/m3, right?

the last question is: since the volumetric value is needed here, instead of the value from the point of solver, why ANSYS fluent didn't add the variable directly in the software?

Thank you.

 

[Rob]

Stuff reacts and heat is released, that will be Watts. But, we may then report that based on cell volume, but in reality we may consider a reactor volume or mass of reactants. Hence you may need to make a distinction between experimental data and Fluent results as in CFD we have different information. 

Not sure about the last point. 

[ll00023]

 

 

I found a source of the heat-of-reaction dimension.

So the heat of reaction variable does show the result based on volume (W/m3). Is this an inconsistency?

since I need to eliminate mesh's impact on the result, is mesh independent test enough for me to say : heat of reaction is not affected by mesh size, just like temperature?

or how to eliminate it in other ways?

you hit the point: the distinction between experimental data and Fluent results.

heat of reaction is Fluent results; why Fluent does not include the variables for experimental data directly?

I need to study the concepts of reaction and heat release further to understand you better.

Thank you.

 

[Rob]

Mesh resolution/independence will ensure you capture the species, thermal and flow field & gradients. That in turn resolves the heat of reaction accuracy. 

CFD and experiment are different. In an experiment I may know I've released 160W, I can get that from CFD but I can also find where that heat was released within the domain. Both are useful.