微小重力下における界面張力差駆動対流の機構とその制御に関する研究

点击翻译按钮获取中文摘要

To suggest new approaches for high quality material processing under micro-gravity condition, systems of surface tension driven convection (Marangoni convection) and its control, e.g. acceleration and deceleration, were studied.In this study, model experiments of Floating Zone Method and Horizontal Bridgeman Method (both two method were usually used on making semiconductor single crystals) were carried out to clarify momentum and heat transfer in laminar flow using model fluid and melt of semiconductor under normal gravity condition and micro-gravity condition utilized parabolic flight and drop shaft. Moreover experimental results were compared with two-dimensional steady numerical simulation.This study clarified effects of physical properties (Prandtl number), temperature difference, length of free surface, depth of melt and strength of magnetic field on surface tension driven convection, effects of gravity, length of free surface and shape of melt on critical condition between laminar and oscillatory flow, and effects of gravity, temperature difference, length of free surface and shape of melt on feature of velocity and temperature oscillation.Transport phenomena in a melt under micro-gravity conditions were clarified. Moreover under normal gravity condition, control of surface tension driven convection is going to make an new approach for high quality material processing possible.