顆粒表面粗糙度在不同旋轉儀轉速下流動行為之探討; Effect of Granular Surface Roughness on Flow Behavior in Different Rotating Drum Speed

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Title:	顆粒表面粗糙度在不同旋轉儀轉速下流動行為之探討;Effect of Granular Surface Roughness on Flow Behavior in Different Rotating Drum Speed
Authors:	胡惠茹;Hui-ju Hu
Contributors:	機械工程研究所
Keywords:	速度場;安息角角度;表面粗糙度;旋轉儀;velocity field;angle of repose;surface roughness;Rotating drum
Date:	2011-07-20
Issue Date:	2012-01-05 12:30:24 (UTC+8)
Abstract:	本論文主要在針對不同表面粗糙度的顆粒體在旋轉儀內的動態行為與傳輸性質進行探討。其中，不同表面粗糙度的顆粒體是把相同物理性質的顆粒與形狀不規則的鋼礫置入振動床磨製完成的。而後再利用Jenike量測儀器，量測出顆粒體的內部摩擦角以及壁面摩擦角，用以檢驗顆粒體的表面粗糙度發生改變。最後把顆粒體(單一類別顆粒，混合不同粗糙度顆粒)置入旋轉儀中，利用高速攝影機拍攝其運動過程，並分析計算出顆粒體在不同表面粗糙度及不同旋轉儀轉速下的安息角角度、流動層厚度，與各項顆粒傳輸性質。實驗結果顯示出不同表面粗糙度的顆粒體對於系統內流場之影響是很大的。當系統中只置入同一粗糙性質的顆粒體時，顆粒體越粗糙將會造成越大的安息角角度，但當顆粒在流動時，因彼此的摩擦力變大會使得流動速度變慢，進一步得知顆粒的擾動速度以及粒子溫度也會隨之減小。其次，當系統中同時置入兩種不同粗糙性質的顆粒體時，顆粒的流場行為是更為複雜的，此時，藉由流動中顆粒所形成之安息角角度的大小，我們可以定義出造成流場行為不同的三個主要效應影響區間(zone)。 In this study, we investigate the effect of particle surface roughness on the dynamic properties in a rotating drum. The particle surface roughness is prepared by using a vibration bed. Then we used Jenike shear tester to measure the internal friction angle and wall friction angle. Finally, the granular flow behavior were recorded by a high-speed camera both mono-dispersed and binary-mixtures granular systems are investigated. Image processing technique to measure the angle of repose, flowing layer thickness and granular transport properties. The results show that the different particle surface roughness causes great influence on granular flow. In the mono-dispersed granular system, the angle of repose increases with the increasing of the internal friction angle, but the average granular velocity, fluctuation velocity and granular temperature decrease with the increasing of the internal friction angle. The granular flowing behavior becomes even more complicated in the binary-mixtures granular system than the mono-dispersed granular system. According to the angle of repose, we can identify three effective dominant zones.
Appears in Collections:	[Graduate Institute of Mechanical Engineering] Electronic Thesis & Dissertation

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