Observations of acetone pool boiling behavior under pulsed laser heating

The variations of temperature on the surface of a specimen and acetone pool boiling behavior under pulsed laser heating are observed transiently. The effects of laser parameters and tiny metal grains on the temperature of the specimen's surface for acetone pool boiling are studied. It is seen that the pulse duration is the main factor that affects the temperature curve and vapor bubble behavior. When the pulse duration increases, the growth time of large vapor bubbles and their departure diameters decrease, but the growth velocity changes little. The growth velocity of large vapor bubbles is different from that under normal conditions. The period of isothermal growth was not observed and the growth velocity rises quickly long after the laser pulse. The process of pool boiling turns vehement when the specimen surface is overlain with tiny metal grains. There are a great number of tiny vapor bubbles continuously generated long after the laser pulse, and the tiny vapor bubble's departure diameter is much less than the value calculated by the classical Fritz formula. © 2001 Scripta Technica, Heat Trans Asian Res, 30(4): 259-266, 2001.