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

本研究的目的是阐明当液滴碰撞到加热表面时，大量微小液滴强烈散射到大气中的小型化现象。特别是，产生的微小气泡（微气泡）的生成行为，其中出现，当液-固接触发生的加热表面和液滴之间形成的薄蒸汽膜的崩溃，被捕获的miniturization机制的说明。在目前使用的石英受热面中，核态沸腾行为一直持续到高温区，而强烈的微小液滴的弥散现象不能被显著识别。然后，将导热性良好的蓝宝石盘、将导电膜薄地溅射到玻璃平面上的ITO（氧化铟锡）膜平面和将铬涂层薄地溅射到石英平面上的平面用作加热表面。利用高速摄像机从每个背面拍摄了每个平面上的沸腾行为，并与石英平面进行了比较。在ITO膜平面和铬涂层平面上的泡核沸腾条件（加热表面和液膜充分润湿的条件的沸腾）的蒸发寿命特性与石英平面中的数据相似。蓝宝石表面的寿命特性接近金属表面的寿命特性。当铬涂层平面的温度超过450°C时，分裂液滴的部分将通过薄的蒸汽膜与加热表面接触。此时，可以确认产生了爆炸性微小液体颗粒的分散。结果表明，这种爆炸性分散的结果是产生了微气泡。

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.