橢球粒子之熱泳與光泳運動

Thermophoretic and photophoretic motions of aerosol spheroids

歐昌霖(Chang-Lin Ou)

指導教授 ： 葛煥彰

國立臺灣大學/工學院/化學工程學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.00450

摘要

本文是以解析方法研究一自由懸浮之橢球形氣膠粒子在一相對於其對稱軸為任意方向的均勻溫度梯度或光射性之熱通量中的熱泳與光泳運動。假設Knudsen數很小以致於流體流動可看似一連續體狀態，且在粒子表面存在有熱滑移現象。在Peclet數和Reynolds數亦很小的情況下，使用雙焦座標系統，可獲得在擬穩定狀態下適當的能量與動量方程式之解。對於長橢球與扁橢球粒子之各種情況，皆可進一步得到熱泳與光泳的速度與作用力。
對於一包含完全相同且無交互作用的橢球粒子懸浮系統而言，本文亦得到隨意方向分佈粒子之平均熱泳與光泳的速度與作用力。結果顯示，橢球粒子之形狀、熱傳導度、以及其相對於施加之溫度梯度或入射光之方位關係，在熱泳與光泳的行為上有著重大的影響。

關鍵字

熱泳 ； 光泳

並列摘要

An analytical study is presented for the thermophoretic and photophoretic motions of a freely suspended aerosol spheroid in a uniform prescribed temperature gradient or radiative heat flux that is oriented arbitrarily with respect to its axis of revolution. The Knudsen number is assumed to be small so that the fluid flow is described by a continuum model with a thermal slip at the particle surface. In the limit of small Peclet and Reynolds numbers, the appropriate energy and momentum equations are solved in the quasisteady situation using the bifocal-coordinate transformations. Explicit expressions for the thermophoretic and photophoretic velocities and forces are obtained for various cases of prolate and oblate spheroidal particles.
The average thermophoretic and photophoretic velocities and forces for an ensemble of identical, non-interacting spheroids with random orientation distribution are also determined. The results indicate that the shape and relative thermal conductivity of a spheroidal particle and its orientation with the thermal gradient or the incident light can have significant effects on its thermophoretic or photophoretic behavior.

並列關鍵字

thermophoresis ； photophoresis

參考文獻

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