Hydrodynamic Drag Force Exerted on a Moving Floc and Its Implications to Free-Settling Test
學年 86
學期 2
出版（發表）日期 1998-03-01
作品名稱 Hydrodynamic Drag Force Exerted on a Moving Floc and Its Implications to Free-Settling Test
作品名稱（其他語言）
著者 Wu, R. M.; Lee, D. J.
單位 淡江大學化學工程與材料工程學系
出版者 I W A Publishing
著錄名稱、卷期、頁數 Water research 32(3), pp.760–768
摘要 This paper numerically evaluates the hydrodynamic drag force exerted on an individual floc moving steadily through an quiescent Newtonian fluid over a wide range of Reynolds numbers. The floc is modelled as a highly porous sphere, whose interior flow field is governed by the combined Darcy–Brinkman model; while the bulk fluid field is governed by Navier–Stokes equations. We used a computational fluid dynamics software, FIDAP 7.5, to solve the fluid field within and around the moving floc, from which the corresponding hydrodynamic drag force exerted on the floc is subsequently obtained. When the floc permeability is rather high, which is usually the case for activated sludge flocs, the drag force was found to be inversely proportional to the floc Reynolds number. The floc density versus size relationship obtained on the basis of the Stokes law-like correlation is thereby applicable to estimate the flocs' fractal dimension, however, is erroneous for estimating the floc density. This paper numerically evaluates the hydrodynamic drag force exerted on an individual floc moving steadily through an quiescent Newtonian fluid over a wide range of Reynolds numbers. The floc is modelled as a highly porous sphere, whose interior flow field is governed by the combined Darcy–Brinkman model; while the bulk fluid field is governed by Navier–Stokes equations. We used a computational fluid dynamics software, FIDAP 7.5, to solve the fluid field within and around the moving floc, from which the corresponding hydrodynamic drag force exerted on the floc is subsequently obtained. When the floc permeability is rather high, which is usually the case for activated sludge flocs, the drag force was found to be inversely proportional to the floc Reynolds number. The floc density versus size relationship obtained on the basis of the Stokes law-like correlation is thereby applicable to estimate the flocs' fractal dimension, however, is erroneous for estimating the floc density.
關鍵字 drag force; floc free-settling; FIDAP; Stokes' law
語言 en
ISSN 0043-1354
期刊性質 國外
收錄於 SCI EI
產學合作
通訊作者
審稿制度
國別 GBR
公開徵稿
出版型式 紙本
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