HEAT TRANSFER IN THE THERMAL ENTRANCE REGION OF AN INTERNALLY HEATED FLOW

The passage of an electrical current through a liquid causes the evolution of heat and when the electrical conductivity depends on the temperature, the rate of evolution varies from point to point in the fluid. Within the thermal entrance region of a duct flow, competition between the rate of evolution and the rate of conduction to bounding surfaces, coupled with differences in residence time between points in planes perpendicular to the flow direction causes local maxima in the temperature field in such planes. The evolution of such temperature fields is studied here using Galerkin's method to approximate solutions of the appropriate differential equation. Temperature fields of this sort influence the electrophoretic migration of small particles in the process known as continuous flow electrophoresis.