for one multiphase reaction:

CaCO3(solid particle)->CaO(solid particle)+CO2(gas)-1.66E6 J/kg,@870 Celsius degree.

In Ansys CFX 10.0, the reaction rate can be easy set, and the mass rate interphase is solved.

But for the the reaction heat of the chemical reaction, the I try set the "HEAT RELEASE" with two kind way,

The first way:

HEAT RELEASE:

Latent Heat = 1.66E6 [J kg^-1]

Option = Latent Heat

Reference Material = caco3

Reference Parent Material = limestone

Reference Temperature = 800 [C]

END

the second way:

HEAT RELEASE:

Option = Specific Enthalpy

Reference Material = caco3

Reference Parent Material = limestone

Reference Pressure = 1 [atm]

Reference Specific Enthalpy = 1.66E6 [J kg^-1]

Reference Temperature = 0 [C]

END

But according to the solution output, the reaction heat is more than the 1.66E6 J/kg.CaCO3 up to 2 times.

I don't understand clearly the reason about it.

Maybe the released CO2 get into the gas phase with formation heat?

Would someone give me hand on this?

thanks in advance!

In order to add the formation enthanpy of CO2 at 298Cdeg and 1 atm, the "HEAT RELEASE" is modified to

H_co2_f*44/100-1.66E6 [J/kg],

but the result is not good.

what's wrong?