Mixed Convective Flow and Heat Transfer of a Dual Stratified Micropolar Fluid Induced by a Permeable Stretching/Shrinking Sheet

Najiyah Safwa Khashi’Ie,Ioan Pop,Ezad Hafidz Hafidzuddin,Norihan Md Arifin,Roslinda Nazar,Nadihah Wahi

doi:10.3390/e21121162

Abstract

The present study accentuates the magnetohydrodynamics (MHD) flow and heat transfer characteristics of a dual stratified micropolar fluid over a permeable stretching/shrinking sheet. Thermal and solutal buoyancy forces are also included to incorporate with the stratification effect. Similarity, transformation is applied to reduce the governing model (partial differential equations) into a set of nonlinear ordinary differential equations (ODEs) due to its complexity. Using bvp4c solver in the MATLAB software, numerical results for some limiting cases are in favorable agreement with the earlier published results. Both assisting and opposing buoyancy flows have dual similarity solutions within specific range of suction and stretching/shrinking parameters, whereas only a distinctive solution is observed for pure forced convective flow. The micropolar fluid shows a disparate pattern of flow, heat and mass transfer characteristics between stretching and shrinking cases. Unlike the shrinking flow, the surface velocity gradient, local Nusselt and Sherwood numbers for stretching flow intensify with the increment of the material parameter. The result from stability analysis reveals that the first solution is the real solution, whereas the second solution is virtual.

Highlights

Nowadays, energy generation becomes a major issue in industrial requirements
The results show that an increment in the magnetic parameter might lessen the velocity, heat and mass transfer rates
The influence of nonlinear thermal radiation, second-order slip and magnetic field on the dual stratified micropolar fluid flow past a vertical stretching sheet was investigated by Sarojamma et al [32]

Summary

Introduction

Energy generation becomes a major issue in industrial requirements. Many attentions are focused to increase the heat transfer rate of the systems which include power stations, chemical plants, air conditioning and petrochemical industry. Khashi’ie et al [27] emphasized the MHD flow and heat transfer with dual stratification effects over a permeable shrinking/stretching sheet using Buongiorno’s model of nanofluid. The influence of nonlinear thermal radiation, second-order slip and magnetic field on the dual stratified micropolar fluid flow past a vertical stretching sheet was investigated by Sarojamma et al [32] They revealed that there was an undershoot in the fluid temperature (negative temperature) due to a strong magnitude of thermal stratification parameter. Inspired by the previous literature, the present work is mainly focused on the MHD flow, heat and mass transfer of micropolar fluid induced by a vertical permeable shrinking/stretching sheet in a dual stratified medium. The authors believe that the present results are significant to other researchers with different backgrounds (mathematics/engineering/physics)

Mathematical Formulation

Stability Analysis

Results and Discussion

Conclusions