Thermocapillary Motion of a Compound Drop in a Concentric Spherical Cavity

• Main Authors: Hsin-I Hsun, 尋歆怡
• Other Authors: Huan-Jang Keh
• Format: Others
• Language: en_US
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/04637533662305446390

碩士 === 國立臺灣大學 === 化學工程學研究所 === 96 === An analytical study is presented for the quasisteady thermocapillary migration of a spherically symmetric compound drop, defined as a spherical fluid drop with a small concentric fluid droplet inside it, situated at the center of a spherical cavity in the limit of negligible Peclet and Reynolds numbers. The applied temperature gradient is constant, and both the drop and the droplet are assumed to retain their spherical shape. To solve the thermal and hydrodynamic governing equations, the general solutions are constructed from the fundamental solutions in spherical coordinates. Analytical results and numerical values for the thermocapillary migration velocity of the compound drop relative to that under identical conditions in an unbounded fluid are presented for various values of the relative viscosity and thermal conductivity of the drop as well as the relative separation distance between the drop and the confining cavity. The presence of the cavity always reduces the drop velocity, irrespective of the relative transport properties of the drop. In general, the boundary effects of the cavity wall on the themocapillary motion of a compound drop can be quite significant in appropriate situations.