Estimation of Floc Permeability and Porosity (short communication)

膠羽透過率及孔隙率的預測（短文）

吳容銘(R.M. Wu) ； 李篤中(D.J. Lee) ； 何品晶(Pinjing He)

《Journal of the Chinese Institute of Chemical Engineers》 34卷2期 (2003/03) Pp. 275-280

https://doi.org/10.6967/JCICE.200303.0275

摘要

本論文簡短的回顧了近來預測污泥膠羽水力透過率的過程，預測污泥膠羽水力透過率的原因之一乃是為了測量污泥膠羽中流體可通過的部分，對多孔性污泥膠羽而言，水力透過率代表了污泥膠羽中大孔洞部份影響了流體在膠羽中的流力行為。以往研究者提出一些透過率模式，進而模擬膠羽的受力情形，但結果往往相差數個數量級。Wu et al.（1998）藉由單顆謬羽在無限流場中逐漸接近一平板的流力方式預測膠羽水力透過率，結果顯示活性污泥膠羽的透過率大於氫氧化銅污泥膠羽，而經過高分子絮凝後的膠羽，以及受剪力作用後的膠羽，其透過率皆減小。氣泡追蹤技術描述了膠羽附近的流場，並且顯示確有流體流過膠羽內部及旁邊，本論文更進一步以膠羽自由沉降的觀點證明以往透過率模式的誤用。

並列摘要

This paper briefly reviewed the progress made recently to the estimation of hydrodynamic permeability of sludge floes, which is essential for determining the extent of advection flow through the floc interior. The large pores mainly contribute the hydrodynamic permeability of sludge floc through which the fluid could readily flow. Permeability models that assume a homogeneous floc interior normally yield marked uncertainties in model outputs. Wu et al (l998) proposed a hydrodynamic approach for estimating the hydrodynamic permeability that considers the response of the sludge floc when moves toward a flat plate. The floc permeability for waste activated sludge was noted higher than the cupric hydroxide sludge, while the polyelectrolyte flocculation and fluid shear could reduce the permeability. The bubble-tracking technique describes the fluid flow field around and through the floc interior. The existence of advection flow is noted unexceptional. The misuse of permeability model has been demonstrated with a case study leading to the floc porosity based on free-settling test.

並列關鍵字

Floc ； Permeability ； Hydrodynamics ； Bubble-tracking ； Advection flow ； Porosity