表面回復模型預測紊流場中熱電效應下氣膠微粒子沉澱行為

Predicting Turbulent Aerosol Particle Deposition Behavior on Thermal and Electric Effects by Surface Rejuvenation Model

王帛偉(Po-Wei Wang)

指導教授 ： 田自力

國立虎尾科技大學/工程學院/車輛工程系碩士班/碩士(2012年)

摘要

本研究論文重點系以表面回復模型之邊界條件，帶入微粒子動量方程及質量守恆方程式求解，求解其溫度場、速度場及濃度場趨勢，並求解分析微粒子沉澱速度。本論文研究中以微粒子在高速流體(Re >10000)下的現象為主，黏滯子層在高雷諾數下黏滯子層平均成長周期經由先前的實驗及公式推導之結果，趨近一定值 為本研究的重要參數。
表面回復模型係指壁面一不備渦流影響之低速區段，此數學模型解微粒子連續動量方程式，將微粒子之總值通量分為擴散通量及對流通量，以簡化其連續動量方程式，求出微粒子在邊界層成長前的傳遞機制及參數；求出微粒子濃度邊界層成長方程式，進而求出微粒子沉澱速度。
而影響微粒子沉澱速度除了本身粒徑的變化外，本文加入探討熱泳力(thermophoresis force)及電場力(electric force)對微粒子沉澱速度的影響。其中熱泳力為主流場與壁面間出現溫度差時將微粒子由熱區帶至冷區的現象，由熱泳速度的公式可看出熱泳力對微粒子沉澱速度的影響。而電場力係指當微粒子受到電離輻射、高壓放射、靜電力及高溫流動場等因素造成微粒子帶電所形成的電泳速度所造成的影響。

關鍵字

表面回復模型 ； 紊流場 ； 熱泳速度 ； 庫倫力 ； 微粒子沉澱速度

並列摘要

In this study ,by using the surface rejuvention model’s boundary condictions to develop the momentum equation and mass conservation equation of particle and find its temperture field and velocity field of particles deposition velocity. In this study we Only concentrate on the behavior of particles on high Rrynolds number(Re>10000). The one of the major value in this study is the average residence time of all eddy liftimes has bee found to trend to near a constent by previous work.

The surface rejuvention model meansthe uninterfer low seed sublayer by eddy this formulating model has been extended to solve simultaneously the particles continuity and momentum equntions, the total particle mass flux is separated into the diffusive and convective components, and then the convective velocity of particle can be predicted thtough the redeced momentum equations, then the net particel flux to the wall can be solve ,then we can find particle deposition velocity.
Also, there are many things can affect the particle deposition velocity. Such as thermophoresis force and electric force are all considered in this study.

並列關鍵字

surface rejuvention model ； turbulent ； thermophoresis velocity ； Coulombic force ； particle deposition velocity

參考文獻

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