Three-dimensional computational fluid dynamics (volume of fluid) modelling coupled with a stochastic discrete phase model for the performance analysis of an invert trap experimentally validated using field sewer solids--颗粒学报PARTICUOLOGY

Mohsin, M., & Kaushal, D. R. (2017). Three-dimensional computational fluid dynamics (volume of fluid) modelling coupled with a stochastic discrete phase model for the performance analysis of an invert trap experimentally validated using field sewer solids. Particuology, 33, 98-111. https://doi.org/10.1016/j.partic.2016.09.010

Three-dimensional computational fluid dynamics (volume of fluid) modelling coupled with a stochastic discrete phase model for the performance analysis of an invert trap experimentally validated using field sewer solids

Mohammad Mohsin, Deo Raj Kaushal ^*

Civil Engineering Department, Indian Institute of Technology Delhi, New Delhi, India

10.1016/j.partic.2016.09.010

Volume 33, August 2017, Pages 98-111

Received 8 March 2016, Revised 16 June 2016, Accepted 21 September 2016, Available online 24 February 2017, Version of Record 13 June 2017.

E-mail: kaushal@civil.iitd.ac.in

Highlights

• 3D-CFD (VOF model) was used with stochastic DPM to predict performance of invert traps.

• Model predicted trap efficiencies were in excellent agreement with the experimentally obtained.

• Flow field predicted by VOF model were in fair agreement with experimental velocities.

• 3D-CFD predicted water surface profile above the invert trap compared well with observed profile.

Abstract

Invert traps are used to trap sewer solids flowing into a sewer drainage system. The performance of the invert trap in an open rectangular channel was experimentally and numerically analysed using field sewer solids collected from a sewer drain. Experiments showed that the free water surface rises over the central opening (slot) of the invert trap, which reduces the velocity near the slot and allows more sediment to be trapped in comparison with the case for the fixed-lid model (assuming closed conduit flow with a shear-free top wall) used by earlier investigators. This phenomenon cannot be modelled using a closed conduit model as no extra space is provided for the fluctuation of the water surface, whereas this space is provided in the volume of fluid (VOF) model in the form of air space in ANSYS Fluent 14.0 software. Additionally, the zero atmospheric pressure at the free water surface cannot be modelled in a fixed-lid model. In the present study, experimental trap efficiencies of the invert trap using field sewer solids were fairly validated using a three-dimensional computational fluid dynamics model (VOF model) coupled with a stochastic discrete phase model. The flow field (i.e., velocities) predicted by the VOF model were compared with experimental velocities obtained employing particle image velocimetry. The water surface profile above the invert trap predicted by the VOF model was found to be in good agreement with the experimentally measured profile. The present study thus showed that the VOF model can be used with the stochastic discrete phase model to well predict the performance of invert traps.

Graphical abstract

Keywords

Computational fluid dynamics model; Invert trap; Sedimentation; Trap efficiency; Retention ratio; Volume of fluid model

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