Interstitial Liquid Effects on the Dynamics of Granular Matter in a Rotating Drum
|Keywords:||顆粒流;粒子追蹤測速法;間隙流體;滾筒;granular flow;PTV;interstitial liquid;rotating drum||Issue Date:||2009||Abstract:||
本論文針對不同間隙流體下顆粒於滾筒內部之運動情形做探討。觀測過程使用高速攝影機搭配粒子追蹤測速法(particle tracking velocimetry)求得混合體於滾筒內之平均行為，發現沉浸顆粒混合體與非沉浸混合體在滾筒中之速度、流動層厚度及顆粒溫度之大小及分佈情況皆明顯不同。藉由觀測到之流場特性做假設，配合體積控制分析(control volume analysis)化簡方程式估計出滾筒中間區塊流動層底部之剪應力，進一步假設應變與應力呈線性之本固關係，計算出混合體內部之等效黏滯係數。由結果得知混合體內部之黏滯係數皆遠大於所加入之間隙流體的黏滯係數，表示混合體內部顆粒間的交互作用為主要之消能機制。
This article focuses on the motion of granular flow in the rotating drum with respect to various interstitial liquids. The average behavior of the mixtures is obtained by employing the high-speed camera with particle tracking velocimetry (PTV). We discovered that the velocity, flowing layer thickness and the granular temperature of the mixtures are different under immersed and non-immersed situations. The momentum equation is simplified by the control volume analysis according to the characteristics of the flow field, and the shear stresses at the bottom flowing layer in the middle of the drum are hence estimated. The effective viscosity of the mixture is obtained from the linear relationship between the shear stress and the shear strain. The viscosity of the mixture is always larger than that of the interstitial fluid. Thus, the interaction among those granulates is the major mechanism of energy dissipation.
|Appears in Collections:||機械工程學系|
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