Effects of power pulsations on natural convection from discrete heat sources.

Abstract

The natural convection heat transfer from an array of heaters flush mounted on a vertical test surface in response to both step and periodic input power has been investigated. Baseline surface temperature measurements in water were obtained for several steady power inputs, ranging from 0.2 W to 1.0 W for the vertical test surface. Also, the effects of the presence of a parallel shroud near the test surface on measured temperature values were studied. The effects of periodic variations in input power on the heater element temperatures were then examined at selected locations. The resulting transient heater temperatures were measured for various amplitudes, frequencies and average levels of the periodic input power. These transient measurements are compared with a two-dimensional numerical simulation of the relevant fluid flow and heat transfer processes. The computed heater surface temperatures supported the trends of the measurements and were within the expected range.