在磁場作用下邊界拉伸及溫度變黏度影 響微粒傳輸之研究

Effect of Electromagnetism on Particle Transports for Flow from a Stretching Surface with Temperature Variable Viscosities

陳啟政(CHI-CHENG CHEN)

指導教授 ： 蔡瑞益

中原大學/工學院/機械工程學系/碩士(2008年)

https://doi.org/10.6840/cycu200900514

摘要

摘要
本文探討氣膠微粒受到熱泳效應和電磁性效應時，對於氣膠微粒
在一平板對稱流之微粒附著速度的影響，這兩種傳輸機制的交互作用
下，對微粒附著速度有相當重要性。本文為不可壓縮、穩態和二維層
流之平板對稱流的模型，其統御方程式包括動量、能量及濃度場方程
式。將統御方程式經過無因次化相似轉換過程後，數值計算方面以
Runge-Kutta 積分法配合射擊法求解，進而計算出氣膠微粒附著速
度，至於微粒粒徑則選擇d m p = 0.01~ 50m 。
同時考慮擴散效應，電磁性效應和熱泳效應時，我們發現當微粒
粒徑很小時(d m p < 1m )，微粒附著速度是受到布朗擴散和熱泳機制影
響。微粒粒徑愈小、溫度差愈大且電磁性效應愈大時，則微粒附著速
度愈大，使得微粒附著通量增加；當微粒為大粒徑時(d m) p >1m ，微粒
附著速度是受到熱泳機制及羅倫茲力的影響，反而電磁性效應對於大
粒徑時較不明顯，且當磁場愈大時，微粒附著速度反而愈小。

關鍵字

磁場作用

並列摘要

ABSTRACT
The study of aerosol particle deposition rate affected by themophoresis
and magnetic effect onto stretching surface is proposed. The interaction
between two transport mechanisms is supposed to be very important for
particle deposition rate. In this study, the air flow was modeled as two
dimensional, incompressible and steady-state laminar flow. The similarity
transformation and numerical technique are used to solve governing
equations include mass, momentum, energy and concerntration. The
solutions are obtained by Runge-Kutta integration method and shooting
method. Then the aerosol particle deposition velocity could be calculated
after solving these governing equations. Particle selected are in a range of
d m p = 0.01- 50m .
When Brownian diffusion, magnetism and thermophoretic effects are
considered, we can find that particle deposition rates are controlled by
Brownian diffusion effect and thermophoretic effect for small particle
sizes( d m p < 1m ). When the particle size is getting smaller which
accompany with larger temperature difference and magnetic effect, the
particle deposition rate and particle flux will increase. Particle deposition
are controlled by thermophoresis and Lorentz force for lager particle sizes( d m p > 1m ), whereas the effect of magnetism isn’t obvious. In
addition, the lager magnetic effect would correspond to the smaller
particle deposition rate.

並列關鍵字

Effect of Electromagnetism

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