Collector efficiency for hydrosol deep-bed filtration of non-Brownian particles at low and finite Reynolds numbers--颗粒学报PARTICUOLOGY

Li, H., & Sansalone, J. (2020). Collector efficiency for hydrosol deep-bed filtration of non-Brownian particles at low and finite Reynolds numbers. Particuology, 53, 124-133. https://doi.org/10.1016/j.partic.2020.03.007

Collector efficiency for hydrosol deep-bed filtration of non-Brownian particles at low and finite Reynolds numbers

Haochen Li ^*, John Sansalone

Engineering School of Sustainable Infrastructure and Environment (ESSIE),, College of Engineering, University of Florida, 217 Black, Gainesville, FL 32611, USA

10.1016/j.partic.2020.03.007

Volume 53, December 2020, Pages 124-133

Received 7 July 2018, Revised 25 February 2020, Accepted 16 March 2020, Available online 23 May 2020, Version of Record 16 December 2020.

E-mail: haochenli@ufl.edu

Highlights

• A filtration model is proposed for Reynolds numbers, Reg from 0.01 to 20.

• Numerical model results are consistent with classical filter models for Re_g < 1.

• Collector efficiency strongly depends on the gravitational number for Re_g > 1.

• Numerical model results yield a modified gravitational number correlation.

• Model implementation can be extended from vertical to horizontal filtration.

Abstract

Aqueous filtration systems with granular media are increasingly implemented as a unit operation for the treatment of urban waters. Many of these aqueous filtration systems are designed with coarse granular media and are therefore subject to finite granular Reynolds numbers (Re_g). In contrast to the Re_g conditions generated by such designs, current hydrosol filtration models, such as the Yao and RT models, rely on a flow solution that is derived within the Stokes limit at low Re_g. In systems that are subject to these finite and higher Re_g regimes, the collector efficiency has not been examined. Therefore, in this study, we develop a 3D periodic porosity-compensated face-centered cubic sphere (PCFCC) computational fluid dynamics (CFD) model, with the surface interactions incorporated, to investigate the collector efficiency for Re_g ranging from 0.01 to 20. Particle filtration induced by interception and sedimentation is examined for non-Brownian particles ranging from 1 to 100 μm under favorable surface interactions for particle adhesion. The results from the CFD-based PCFCC model agreed well with those of the classical RT and Yao models for Re_g< 1. Based on 3150 simulations from the PCFCC model, we developed a new correlation for vertical aqueous filtration based on a modified gravitation number, N_G^*, for the initial deep-bed filtration efficiency at lower yet finite (0.01 to 20) Re_g. The proposed PCFCC model has low computational cost and is extensibile from vertical to horizontal filtration at low and finite Re_g.

Graphical abstract

Keywords

Deep-bed filtration; Granular filtration; Unit operations; Stormwater; Urban water; Urban drainage

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