Transient heat transfer in porous media.

Abstract

The general differential equations describing unsteady-state heat transfer with a fluid flowing through a porous medium are derived. These equations represent a physical model for heat transfer in thermal oilrecovery process, packed-bed chemical reactors, and heat regenerators. Fluid-solid convective heat transfer and longitudinal conduction in both the fluid and solid phases are considered. Laplace transformation and numerical inversion are used to solve the system of partial differential equations. A digital computer program obtains the numerical results which are compared to those of Green and Perry using finite difference technique, and to experimental data of Preston. Also presented are analytical solutions for the cases where the longitudinal conduction is neglected and the convective heat transfer coefficient is assumed to be infinite. These solutions are programmed and results are compared to those from the general case. The effect of different heat transfer mechanisms on temperature profiles at low fluid velocities is studied. The results show that this numerical method gives accurate results with relatively short computational time.