MHD Flow and Heat Transfer of Hybrid Nanofluid over an Exponentially Shrinking Surface with Heat Source/Sink

Mohamad Nizam Othman,Alias Jedi,Nor Ashikin Abu Bakar

doi:10.3390/app11178199

Abstract

In nanotechnology research, nanofluid technology contributes many applications to engineering applications and industry, such as power generation, solar collection, heat exchangers for cooling, and many more. However, there are still a few constraints in terms of heat transfer enhancement, although nanofluid properties show the best heat transfer rate compared with conventional fluids. Thus, this study was conducted for the purpose of investigating the behaviors of flow and heat transfer of hybrid nanofluid with carbon nanotubes (CNTs) on a permeable exponentially shrinking surface, as well as investigating the effects of a magnetic field and heat source/sink. This study was conducted by developing a mathematical model, which was the Tiwari–Das model for momentum and energy equations, and then transforming the model’s partial differential equations (PDEs) to ordinary differential equations (ODEs) using a similarity solution. Next, these equations were solved numerically using the MATLAB bvp4c boundary value problem solver. The authors particularly explored these behaviors with a few variations. Based on the results obtained, it was found that dual solutions exist in a specific range of the shrinking case, λc<λ<−λ and that the critical point λc also exists in a range of −1.5 < λc < −1 with different parameters. For the heat source/sink effect, the Nusselt number was higher when heat sink case ε < 0, whereas it decreased when the heat source case ε > 0. Therefore, this study deduced that the heat transfer rate of hybrid nanofluid (CNTs/Cu–water) is better than regular nanofluid (CNT–water) and conventional fluid (water). The present study took into consideration the problem of MHD flow and heat transfer analysis of a hybrid nanofluid towards an exponentially shrinking surface with the presence of heat source/sink and thermal radiation effects. The authors show that dual solutions exist within a specific range of values due to the shrinking case. The current work is predicted to have numerous benefits in equivalent real-world systems.

Highlights

In the past decade, there has been a global trend resulting from the discovery of hybrid nanofluid for heat transfer enhancement
This study deduced that the heat transfer rate of hybrid nanofluid (CNTs/Cu–water) is better than regular nanofluid (CNT–water) and conventional fluid
The present study took into consideration the problem of MHD flow and heat transfer analysis of a hybrid nanofluid towards an exponentially shrinking surface with the presence of heat source/sink and thermal radiation effects

Summary

Introduction

There has been a global trend resulting from the discovery of hybrid nanofluid for heat transfer enhancement. Khashi ie et al [23] conducted a comparative analysis about flow and heat transfer of hybrid nanofluid over a permeable shrinking cylinder with Joule heating Their results indicated that suction could hold the boundary layer separation by inducing the flow and increasing the heat transfer rate. The investigation of boundary layer flow and heat transfer past an exponentially shrinking surface has gained more attention, as it finds important applications in many industries and manufacturing processes. Driven by the above reviews, the present paper was devoted to determining numerical solutions to MHD boundary layer flow and heat transfer of hybrid nanofluid over a permeable exponentially shrinking surface with a magnetic field, heat sink/source, and thermal radiation effect. The present results obtained were compared with previously published results, indicating good agreement

Mathematical Methods

Numerical Analysis

Results and Discussion