Following formulation is used for conducting thermal FEA.

ρcpTt(kT)=qVol \rho_{cp} \frac{\partial T}{\partial t} - \nabla \cdot (k \nabla T) = q_Vol

ρcp \rho_{cp} is the volumetric heat capavity

k k is the thermal conductivity

qVol q_Vol is the volumetric heat generation.