MEASUREMENT OF HEAT-TRANSFER AT THE PHASE INTERFACE OF CONDENSING BUBBLES

Using holographic interferometry and high-speed cinematography the heat transfer at the phase interface of vapor bubbles condensing in a subcooled liquid of the same substance was measured with ethanol, propanol, refrigerant R113 and water. To evaluate the axisymmetric temperature field around the bubble from the interference fringe field, the Abel integral method is not sufficient. A correction procedure considering the light deflection caused by the local temperature gradient has been developed and applied to calculate the heat transfer coefficient. The measurements were performed in the range 2 < Pr < 15 and 1 < Ja < 120. Measured data could be well-correlated as functions of the Prandtl and Reynolds numbers for the heat transfer coefficient and as functions of the Reynolds, Prandtl and Jacob numbers for the bubble collapse time.