High-heat-flux forced convection boiling from small regions

Results of an experimental investigation of boiling heat transfer from small heat sources to a subcooled flow are presented. The heater patch is on the floor of a 10 mm wide by 3 mm high rectangular channel. Platinum heater patches with streamwise lengths of 1.0 mm and 3.0 mm are used. A thin film of platinum deposited on a quartz substrate serves as an integrated heater element and resistance thermometer. An inert fluorocarbon liquid (FC-72) is circulated through the channel at velocities up to 8.6 m/s with pressures up to 274 kPa and subcooling values from 13 to 46°C. The results show that a temperature excursion occurs upon incipience of nucleate boiling which is unaffected by changes in the heated length.