Thermal and Fluid Dynamics Performance of MWCNT-Water Nanofluid Based on Thermophysical Properties: An Experimental and Theoretical Study

Zongjie Lyu,Ibrahim M Alarifi,Amin Asadi,Vakkar Ali,Loke K Foong

doi:10.1038/s41598-020-62143-3

Abstract

There are many debates on the preparation methods and the role of ultrasonication on the stability, thermophysical properties, and heat transfer performance of nanofluids. The present study, which is the continuation of the authors previous study, the effects of ultrasonication on the thermal and fluid dynamic performance of MWCNT-water nanofluid, over a different range of temperatures and solid concentrations, based on the thermophysical properties of the nanofluid, has been investigated. The effects of ultrasonication time on the stability and thermophysical properties of the nanofluid were studied over 30 days of the samples preparation. The thermophysical properties of the nanofluid have been experimentally measured at the optimum ultrasonication time. Using the experimental data, and employing different figures-of-merit, the effects that the addition of MWCNTs had on the heat transfer effectiveness and pumping power have been studied. It was confirmed that the nanofluid is a good heat transfer fluid, with a negligible penalty in pumping power. The thermal and fluid dynamic performance of the nanofluid in a microchannel heat sink has also been studied, by comparing the enhancement ratio of the convective heat transfer coefficient and the increase in pumping power.

Highlights

Www.nature.com/scientificreports the thermophysical properties of nanofluids is the first step towards evaluating their HTP in practical applications[32,33]
The results showed that the maximum thermal conductivity, which is highly desirable in heat transfer applications, occurred at the ultrasonication time of 60 min, solid concentraion of 0.5 vol %, and temperature of 60 °C, was under 30%
Adding MWCNT resulted in a negligible increase in the dynamic viscosity and a considerable enhancement in the thermal conductivity of the base fluid

Summary

Introduction

Www.nature.com/scientificreports the thermophysical properties of nanofluids is the first step towards evaluating their HTP in practical applications[32,33]. Cabalerio et al.[50] have studied the HTP of water-EG (90–10%) nanofluid containing graphene nanoplatelets over different ranges of solid concentrations and temperatures They measured the dynamic viscosity and thermal conductivity of the nanofluid. Zyla[51] investigated the HTP of MgO-EG nanofluid at different temperatures and solid concentrations based on Prasher et al.[48] and Mo number[49] FOMs. There are a limited number of studies in the current literature on the HTP of nanofluids, based on different FOMs, before conducting experimental tests on heat transfer. In the current study, the effects of adding MWCNT into water, and the ultrasonication time, on the thermal effectiveness and PP over different ranges of temperature and solid concentrations, in fully developed internal laminar and turbulent flow regimes, will be investigated. The thermal and fluid dynamics performance will be evaluated, and the results will be presented and discussed

Objectives

Methods

Results

Conclusion