Heat Transfer Behavior on Small Horizontal Heaters During Pool Boiling of FC-72

Abstract

Detailed local measurements of wall heat flux during saturated pool boiling of FC-72 on a small heated area without sidewalls were made using an array of 96 temperature-controlled heaters. Data were obtained in the nucleate boiling, critical heat flux, and transition boiling regimes. The space and time resolved data were used to conditionally sample the heat flux according to whether or not boiling occurred on the surface, enabling the separation of the heat flux due to boiling from that due to natural convection or vapor contact. The heat transfer from the edge heaters was observed to be much higher than that for the inner heaters above the critical temperature. The heat transfer during liquid contact in transition boiling was constant for a given wall superheat for the inner heaters, and was observed to decrease with increasing wall superheat.