NATURAL CONVECTION FROM A BURIED PIPE WITH EXTERNAL BAFFLES

Abstract

Numerical solutions are presented for the natural convection heat transfer from a pipe with two baffles attached along its surface buried beneath a semi-infinite, saturated, porous medium. The surface of the medium is assumed to be permeable. The governing equations for Darcy flow are solved using finite differences. The complicated geometry is handled through the use of a body-fitted curvilinear coordinate system. Results are presented for three baffle lengths and a range of burial depths and Rayleigh numbers. The numerical simulations indicate that substantial energy savings can be realized if baffles are used. The results obtained in terms of the Nusselt number for the case of no-baffle are in excellent agreement with analytical and experimental results available in the literature. A simple correlation for Nu has been developed as a function of Ra, pipe burial depth h/R, and baffle length l/R.