短脉冲激光作用下丙酮液池沸腾现象的瞬态观测

INSTANT OBSERVATION ON THE ACETONE POOL BOILING BEHAVIOR UNDER PULSED LASER-HEATED

本文对短脉冲激光作用下试件表面的温度变化和丙酮液体汽泡行为进行了瞬态观测，研 究了激光参数和细小金属颗粒等因素对丙酮液体沸腾行为的影响。结果表明：激光参数中，脉宽是 影响温度曲线和汽泡行为的主要因素，随着激光脉宽增大，大汽泡的长大时间和脱离直径减小；汽 泡长大速度与常规沸腾时的完全不同，没有出现等温生长阶段，在激光脉冲后很长时间内汽泡长大 速度快速增大；试件表面覆盖细小金属颗粒后，沸腾过程变得非常剧烈。

The variations of temperature on the surface of specimen and acetone pool boiling behavior under pulsed laser-heated are observed instantly. The affections of laser parameters and tiny metal grains on the temperature of specimen's surface and acetone pool boiling behavior are studied. It shows that the pulse width is the main factor that affects the temperature curve and vapor bubble behavior. When the pulse width goes up, the growth time of large vapor bubble and its departure diameter decrease, but its growth velocity changes little. The growth velocity of large vapor bubble is different from which is under normal condition - the phase of isothermal growth has not been observed and the growth velocity rises quickly long after laser pulse. The process of pool boiling turns to be vehemently when the surface of specimen is overlaid with tiny metal grains.