CFD-based analysis of entropy generation in turbulent double diffusive natural convection flow in square cavity

Khaled Said,Amina Sabeur,Ahmed Ouadha

doi:10.1051/matecconf/202033001023

Abstract

The present study concerns the problem of natural and double diffusive natural convection inside differentially heated cavity filled with a binary mixture composed of air and carbon dioxide (CO2). Temperature and CO2 concentration gradients are imposed on both perpendicular left and right walls. Simulations have been performed using the CFD commercial code ANSYS Fluent by solving continuity, momentum, energy and species diffusion equations. Numerical results obtained have been compared to data from the literature for both natural convection thermosolutal cases under laminar and turbulent regimes. For turbulent runs the RNG k-ε model has been selected. A good agreement has been noted between the different types of data for both cases for Rayleigh number ranging between 103 and 1010 and buoyancy ratio between -5 and +5. Entropy generation rates due to thermal, viscous and diffusive effects have been calculated in post processing for all cases.

Highlights

In the last decades great effort has been devoted to the study of natural convection [1,2,3]
Thermosolutal convection phenomena can be controlled through number of non-dimensionless parameters namely RaT, Le, Pr, and RaS or N
The numerical simulations for the first case consist of two dimensional square enclosure filled with air to handle the issue of free convection in steady laminar and turbulent regime reported by several authors

Summary

Introduction

In the last decades great effort has been devoted to the study of natural convection [1,2,3]. An intensive study was performed in order to determine the influence of a wide range of non-dimensional parameters on double diffusive convection by means of numerical simulation They concluded that the thermal and solutal Rayleigh number beside of Lewis number has an observable impact on thermosolutal convection. Koufi et al [5] carried out CFD numerical simulation in order to investigate laminar double diffusive free convection in square enclosure subjected to uniform temperature and concentration gradients. They found that the thermoslutal flow depends strongly on the buoyancy ratio. Similar studies have been the subject of several authors [7,8]

Methods

Results

Conclusion