A Computational Fluid Dynamics (CFD) prediction procedure for computing the internal hydrodynamic behaviour of final clarifiers is presented. Calculations are carried out and presented for comparison with experimental measurements of point velocities in a shallow circular clarifier in operation at a UK waste water treatment works. The calculations compare favourably with the data and the model ...

Agile manufacturing (AM) is a 21 century concept in manufacturing firm intended to improve the competitiveness of firms. Manufacturing process based on AM is characterized by customer-supplier integrated process for product design, manufacturing, marketing and support services. This needs decision-making at functional knowledge levels, stable unit cost, flexible manufacturing, easy access to in...

In an attempt to reduce the high computational efforts for dynamic thermal simulations using Computational Fluid Dynamics (CFD) the authors have recently developed an adaptive freeze-flow method (i.e. freezing of flow equations over variable time periods). This paper documents the work that has been carried out to predict the radiative surface heat transfer in dynamic thermal building processes...

In this work, CFD is used to simulate the flow in an existing thermal labyrinth located at the basement of a hospital building. This labyrinth is an underground channel equipped with water tanks to increase the thermal mass and reduce the heating and cooling demand of the building. Thermal energy storage in the water tanks is a complex heat transfer phenomena involving turbulent forced convecti...

We present a CFD model that predicts the sedimentation of activated sludge in a full-scale circular secondary clarifier that is equipped with a suction-lift sludge removal system. The axisymmetric single-phase model is developed using the general-purpose CFD solver FLUENT 6, which uses the finite-volume method. A convection-diffusion equation, which is extended to incorporate the sedimentation ...

This paper presents CFD simulations of natural displacement ventilation airflows in which the buoyancy force produced by a heat source is opposed by a wind force. Cases investigated focus on windbuoyancy force relationships for which a two-layer stratification is maintained. CFD predictions of the position of the interface separating the two layers and the change in reduced gravity (temperature...

This study aims to incorporate most recent multiphase models in order to investigate the hydrodynamic behaviour of a TBR in terms of pressure drop, liquid holdup and catalyst wetting efficiency. Taking into account transport phenomena such as mass and heat transfer, an Eulerian k-fluid model was developed resulting from the volume averaging of the continuity and momentum equations and solved fo...

Numerical flow models have been widely applied in engineering disciplines for many years. In the last few years, there has been a proliferation of the use of Computational Fluid Dynamics (CFD) in the fields of geomorphology and hydrology (see Bates and Lane, 1998). These models enable an improved simulation of important processes providing prediction fields that allow considerable insight into ...

Understanding mixing times for transient pollutants in mechanically ventilated rooms is important for resilience and safety planning for accidental releases of toxic material. There is a lack of information on the ability of simple models available to predict these times for ventilated spaces with different geometries and ventilation configurations. Three analytical mixing time models, includin...