磁性顆粒在磁場與流場交互作用下之凝絮情形

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Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/3520

Title:	磁性顆粒在磁場與流場交互作用下之凝絮情形
Authors:	薛人豪;jen-hao hsueh
Contributors:	環境工程研究所
Keywords:	碎形維度;凝絮速率;磁性顆粒;fractal dimension;rate of aggregation;magnetic particle
Date:	2007-03-23
Issue Date:	2009-09-21 12:17:27 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	本研究探討磁性顆粒受磁場及流場交互作用下的凝絮情形，利用影像擷取系統及分析軟體，在不同磁場方向設定下分別探討磁場及流場對凝絮的影響，最後利用無因次參數，做出凝絮速率的迴歸模式。結果發現，在粒徑長成方面，磁場強度的增強對凝絮的速率及粒徑成長皆有提升的作用；在不同流速下，則會因Cm-s值的不同而有相異的凝絮情形：Cm-s值在大於1的情況下，若流速增加則會使得凝絮速率增加，在Cm-s值小於1的情況下，流速上升反而使得凝絮物成長到達一定時間即停止。在碎形維度方面，磁場強度若升高，碎形維度會有上升的情形，而流速的變化對碎形維度並沒有明顯的影響。最後，利用凝絮速率V與無因次參數Cm-s所得到的迴歸模式為：V=－0.096318＋0.326564×√Cm-s，做出來的迴歸式可利用計算出的Cm-s值，來預測其凝絮速率。 In this study, aggregation of magnetic particles is affected by the interaction of external magnetic field and flow rate. We analyze the result of aggregation with different direction of external magnetic field, respectively. The circumstances of aggregation are investigated via microscopic visualization system and digital image analysis. Finally, the regression of aggregation is made by dimensionless parameter. In the result, the rate of aggregation are increasing by enhancing the external magnetic field in all cases. But in different flow rate, the circumstances of aggregation are changed by the value of dimensionless parameter ,Cm-s. When Cm-s is greater than 1, the rate of aggregation are increasing by increasing the flow rate. On the contrary, the aggregations are broken by the shear force when Cm-s smaller than 1. In the result of fractal dimension, enhancing the external magnetic field will obtain larger fractal dimension. The flow rate cause no effect to fractal dimension. The regression analysis is made by rate of aggregation, V and dimensionless parameter, Cm-s. The result of regression is V=－0.096318＋0.326564×√Cm-s We can use this model to predict the rate of aggregation.
Appears in Collections:	[Graduate Institute of Environmental Engineering ] Electronic Thesis & Dissertation

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