Controlled cooling of a hot plate with a water jet

Abstract

Experiments are performed, under steady-state conditions, to study the boiling heat transfer from a hot plate to a planar jet of water. Temperature control of the heating surface enables the determination of entire boiling curves and the identification of each boiling regime from forced convection to film boiling. By solving the two-dimensional inverse heat conduction problem the local heat flux and corresponding temperature can be computed up to a distance of 55 mm from the stagnation line. Measurements are carried out under atmospheric pressure in a heater temperature range from 100 to 650 °C. The jet temperature is varied to study the influence of subcooling in any regime of the boiling curve. Furthermore experiments are carried out with variable jet velocity and distance between nozzle and heater, for an immersed jet and for a free surface jet, respectively. The transition from nucleate to film boiling at the stagnation point can clearly be determined. Film boiling occurs, e.g., at about 450 °C surface temperature at a jet velocity of 0.8 m/s and a subcooling of 16 K.