Heat Transfer Enhancement and Hydrodynamic Characteristics of Nanofluid in Turbulent Flow Regime

Mohammad Nasiri-Lohesara

doi:10.1155/2015/814717

Abstract

Turbulent forced convection ofγ-Al2O3/water nanofluid in a concentric double tube heat exchanger has been investigated numerically using mixture two-phase model. Nanofluids are used as coolants flowing in the inner tube while hot pure water flows in outer tube. The studies are conducted for Reynolds numbers ranging from 20,000 to 50,000 and nanoparticle volume fractions of 2, 3, 4, and 6 percent. Results showed that nanofluid has no effects on fully developed length and average heat transfer coefficient enhances with lower slope than wall shear stress. Comparisons with experimental correlation in literature are conducted and good agreement with present numerical study is achieved.

Highlights

With progresses of technology heat transfer augmentation is one of the most challenges for developing Hi-tech industries.Application of additives to liquids is one way of enhancing heat transfer
The results showed heat transfer enhances with increasing particles volume concentration and Reynolds number and it showed that two-phase models for the simulation of nanofluid are satisfactory with comparing of experimental data
Results show fully developed region for X/D = 45 for different nanoparticle volume fraction and pure water that proves nanofluid has no effects on fully developed length

Summary

Introduction

With progresses of technology heat transfer augmentation is one of the most challenges for developing Hi-tech industries. Application of additives to liquids is one way of enhancing heat transfer. Augmenting of fluid thermal conductivity is the main purpose in improvement of the heat transfer characteristic of liquids. Progress in material engineering and developing new technologies cause the basis of producing nanosized particles. Masuda et al [1] introduced the liquid suspension of nanosized particles and Choi [2] for the first time proposed the name of nanofluid to this suspension. Nanofluids change the thermal and hydraulic feature of base fluids and cause enormous heat transfer enhancement

Objectives

Methods

Results

Conclusion