Entrance Region Flow of Herschel-Bulkley Fluid in an Annular Cylinder

Rekha G Pai,A Kandasamy

doi:10.4236/am.2014.513189

Abstract

The entrance region flow of a Herschel-Bulkley fluid in an annular cylinder has been investigated numerically without making prior assumptions on the form of velocity profile within the boundary layer region. This velocity distribution is determined as part of the procedure by cross sectional integration of the momentum differential equation for a given distance z from the channel entrance. Using the macroscopic mass and momentum balance equation, the entrance length at each cross section of the entrance region of the annuli and pressure distribution have been calculated for specific values of Herschel-Bulkley number and various values of aspect ratio and flow behavior index. The effects of non-Newtonian characteristics and channel width on the velocity profile, pressure distribution and the entrance length have been discussed.

Highlights

The entrance region flow in channels constitutes a problem of fundamental interest in engineering applications such as nuclear reactors, polymer processing industries, haemodialyzers and capillary membrane oxygenators
The behavior of the fluid in the entrance region may play a significant part in the total length of the channel and the pressure drop may be markedly greater than for the case where the flow is regarded as fully developed throughout the channel
From the present study of the entrance region flow of Herschel-Bulkley fluid in an annuli, the following conclusion can be drawn: 1) The entrance length decreases when the width of annuli decreases for any particular Herschel-Bulkley fluid

Summary

Introduction

The entrance region flow in channels constitutes a problem of fundamental interest in engineering applications such as nuclear reactors, polymer processing industries, haemodialyzers and capillary membrane oxygenators. In such installations, the behavior of the fluid in the entrance region may play a significant part in the total length of the channel and the pressure drop may be markedly greater than for the case where the flow is regarded as fully developed throughout the channel. How to cite this paper: Pai, R.G. and Kandasamy, A. (2014) Entrance Region Flow of Herschel-Bulkley Fluid in an Annular Cylinder.

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