NATURAL-CONVECTION HEAT-TRANSFER IN A NONUNIFORM FINITE ANNULUS WITH CONCENTRIC HEAT-SOURCE

In this paper, the mechanisms of natural-convection heat transfer insi de a nonuniform finite annulus have been numerically investigated. The system is actually a streamlined, water-filled latex balloon with a c oaxial cylindrical heating element. The balloon can be applied as a lo cal hyperthermia treatment device for the removal of undesirable tissu e if sufficiently high temperatures and preferably uniform surface hea t fluxes can be maintained. A validated control-volume-based method ha s been employed to solve the coupled transient three-dimensional trans port equations for laminar free convection. The effects of heat-source temperature distributions and device orientations on the heat transfe r have been studied. Possible design improvements of this device are d iscussed.