Effect of Magnetic Field on Entropy Generation in a Microchannel Heat Sink with Offset Fan Shaped

Mohammad Nasiri,Giulio Lorenzini,Mohammad Rashidi

doi:10.3390/e18010010

Mohammad Nasiri, Giulio Lorenzini + Show 1 more

Open Access

https://doi.org/10.3390/e18010010

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Journal: Entropy	Publication Date: Dec 29, 2015
Citations: 43	License type: CC BY 4.0

Affiliation: University of Parma, University of Tabriz

Abstract

In this study, convection flow in microchannel heat sink with offset fan-shaped reentrant cavities in sidewall filled with Fe3O4-water is numerically investigated. The effects of changing some parameters such as Reynolds number and magnetic field are considered. The nanofluid flow is laminar, steady and incompressible, while the thermo-physical properties of nanoparticles were assumed constant. A finite volume method and two phase mixture models were used to simulate the flow. The obtained results show that the frictional entropy generation increases as Reynolds number increases, while a reverse trend is observed for thermal entropy generation. By applying a non-uniform magnetic field, the entropy generation due to heat transfer decreases at first and then increases. When using the uniform magnetic field, the frictional entropy generation and thermal entropy generation is negligible. For all studied cases, the total entropy generation decreases using non-uniform magnetic fields. The results indicate that by increasing the magnetic field power, the total entropy generation decreases.

Highlights

With the development of science and technology, the decreasing size of the systems has many advantages in comparison with conventional size, including optimized size, accessiblity, and enhance functionality
The heat transfer of flowing fluids is limited according to the thermal properties of fluids
The results show that the average frictional entropy generation increases as Reynolds number increases

Summary

Introduction

With the development of science and technology, the decreasing size of the systems has many advantages in comparison with conventional size, including optimized size, accessiblity, and enhance functionality. Microchannels are the basic structures in these systems. Microchannels have become very important is some industries and engineering applications such as heat pumps, heat exchangers, medical and aerospace devices. The optimal design of microchannels depends considerably on their thermal efficiency. Tuckerman and Pease [1] studied hydrothermal behavior in microchannels for the frist time. The heat transfer of flowing fluids is limited according to the thermal properties of fluids

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