3D Simulation of Incompressible Poiseuille Flow through 180° Curved Duct of Square Cross-section under Effect of Thermal Buoyancy

Oluwole Daniel Makinde,Mourad Mokeddem,Houssem Laidoudi,Mohamed Bouzit

doi:10.3311/ppme.12773

Abstract

In this paper, three-dimensional numerical simulations are carried out to investigate and analyze the gradual effects of thermal buoyancy strength on laminar flow of an incompressible viscous fluid and heat transfer rate inside a 180° curved channel of square cross-section. The governing equations of continuity, momentum and energy balance are obtained and solved numerically using finite volume method. The effect of Dean number, De, and Richardson number, Ri, on dimensionless velocity profiles and Nusselt number are examined for the conditions: De = 125 to 150, Ri = 0 to 2 at Pr = 1. The mean results are illustrated in terms of streamline and isotherm contours to interpret the flow behaviors and its effect on heat transfer rate. Dimensionless velocity profiles and the local Nusselt number at the angle 0° and 90° are presented and discussed. Also, the average Nusselt number on surfaces of curved duct is computed. The obtained results showed that by adding thermal buoyancy to computed domain, some early Dean vortices are observed at the angle 0° and new sort are observed at 90°. Furthermore, increase in Dean number increases the heat transfer rate. In other hand, increase in Richardson number decreases the average Nusselt number of 180° curved duct.

Highlights

The flow patterns and its effects on heat transfer in curved ducts have been investigated by huge number of researchers due to the complexities and critical importance of this kind of flow
The effect of Dean number, De, and Richardson number, Ri, on dimensionless velocity profiles and Nusselt number are examined for the conditions: De = 125 to 150, Ri = 0 to 2 at Prandtl number (Pr) = 1
The results showed that some alternative vortices are seen to be appeared on duct walls and its number is seen to be increased with gradual increase in Richardson number as well as Reynolds number

Summary

Introduction

The flow patterns and its effects on heat transfer in curved ducts have been investigated by huge number of researchers due to the complexities and critical importance of this kind of flow. Tremendous mechanical and chemical processing applications frequently confront a forced flow through a curved duct. Examples involving the flow inside tube type heat exchangers of high performance, refrigeration systems, oil refineries, device of food treatments, nuclear station, chemical process, etc. From analyzes of previous researches in this field [1,2,3,4,5,6,7,8,9,10], it was found that the flow patterns inside a curved tubes are completely different from the flow patterns through straights ducts. The deference of flow pressures between main flow and secondary flow create some vortices called Eckman vortices or end cells. This definition is given by Finlay and Nandakumar [1]

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