A RESEARCH ON RAPID EVAPORATION OF THE MICRO BUBBLE AND ITS INJECTION-COLLAPSE BEHAVIOR

本研究的目的是为了阐明大量微小液滴在受热面上碰撞时强烈分散到大气中的小型化现象。特别是，为了解释微型化机理，捕捉到了微气泡(微气泡)的产生行为，该微气泡是由于加热面与液滴之间形成的薄汽膜坍塌而发生液-固接触时产生的。在迄今使用的石英加热面上，晶核沸腾行为一直持续到高温范围，强烈的微小液滴的分散现象并不明显。然后，采用导热性好的蓝宝石圆盘、在玻璃平面上溅射导电膜的ITO(Indium Tin Oxide)薄膜平面和在石英面上溅射镀铬层的平面作为加热表面。用高速摄像机从每个背面捕捉到每个平面上的沸腾行为，并与石英平面进行了比较。ITO薄膜平面和镀铬层平面上的成核沸腾状态(受热面和液膜充分湿的状态下的沸腾)的蒸发寿命特性与石英面上的数据相似。从蓝宝石光泽的寿命特性到金属表面的寿命。当镀铬层温度超过450℃时，分离出的液滴部分通过薄的蒸汽膜与受热面接触，从而证实了爆炸性微小液体粒子的分散。实验证明，这种爆炸性分散的结果是微气泡。

The purpose of this study is to clarify the miniaturization phenomenon in which large number of minute droplets intensely scatters to the atmosphere, when the droplet collided on the heating surface. Especially, the generation behavior of the minute bubble(micro bubble), which arose, when the liquid-solid contact occurred by a collapse of the thin vapor film formed between the heating surface and the droplet, was caught for the elucidation of the minituarization mechanism. In quartz heating surface used until now, the nucleate boiling behavior continued to the high-temperature range, and the dispersion phenomena of the intense and minute droplets could not be remarkably recognized. Then, sapphire disk of which thermal conductivity is good, ITO(Indium Tin Oxide)film plane which thinly spattered conductive film to the glass plane and the plane which thinly spattered chromium coating on the quartz plane were used as a heating surface. Boiling behavior on each plane was caught by high-speed camera from each back surface, and it was compared with the quartz plane. Evaporation lifetime property of the nucleate boiling condition(boiling of the condition in which heating surface and liquid film sufficiently got wet)on the ITO film plane and the chromium coating plane is similar to the data in the quartz plane. The lifetime property on the sapphire closs to the lifetime for metal surface. The part of divided droplet would contact with heating surface through the thin vapor film, when the temperature of the chromium coating plane exceeds 450°C.At this time, it could be confirmed that the dispersion of the explosive minute liquid particle was generated. It was proven that the result of inducing this explosive dispersion was a micro bubble.