I am following this paper:

The solid phase is a combustible material which burns and turns to gas and also releases energy.

I included the energy released as a source term in energy equation and the mass transfer from solid to gas using DEFINE_MASS_TRANSFER.

For this case, is it necessary to mention the enthalpy of formation for the materials? I took the enthalpy of formation as 0 for gas and solid and performed the simulation.

The pressure is not rising as rapidly as in the paper and the solid is also burning slower than in the paper.

In that paper nothing is given about the enthalpy of formation in material properties.Can you please help.I am not getting what I did wrong.