Radial injection of a hot fluid into a cold porous medium: the effects of local thermal nonequilibrium

We consider the manner in which local thermal nonequilibrium effects influence the development of the thermal field when a hot fluid is injected radially into a cold porous medium. A purely forced convection situation is considered, and the evolving thermal fields depend on four non-dimensional parameters, including the Péclet number and the nondimensional interphase heat-transfer coefficient, H. In this primarily numerical study we find that local thermal equilibrium is always attained eventually, but after a time which depends strongly on the value of H. When the Péclet number is large a thermal shock wave is formed within the fluid phase which degrades slowly by imparting heat to the solid phase.