Experimental Study of Halloysite Nanofluids in Pool Boiling Heat Transfer.

Thong Le Ba,Ahmed Baqer,Lezsovits Ferenc,Gyula Gróf,Mohammed Saad Kamel,Somchai Wongwises,Vincent Otieno Odhiambo,Imre Miklós Szilágyi

doi:10.3390/molecules27030729

Abstract

Halloysite nanotube (HNT) which is cheap, natural, and easily accessible 1D clay, can be used in many applications, particularly heat transfer enhancement. The aim of this research is to study experimentally the pool boiling heat transfer (PBHT) performance of novel halloysite nanofluids at atmospheric pressure condition from typical horizontal heater. The nanofluids are prepared from halloysite nanotubes (HNTs) nanomaterials-based deionized water (DI water) with the presence of sodium hydroxide (NaOH) solution to control pH = 12 to obtain stable nanofluid. The nanofluids were prepared with dilute volume concentrations of 0.01–0.5 vol%. The performance of PBHT is studied via pool boiling curve and pool boiling heat transfer coefficient (PBHTC) from the typical heater which is the copper horizontal tube with a thickness of 1 mm and a diameter of 22 mm. The temperatures of the heated tube surface are measured to obtain the PBHTC. The results show an improvement of PBHTC for halloysite nanofluids compared to the base fluid. At 0.05 vol% concentration, HNT nanofluid has the best enhancement of 5.8% at moderate heat flux (HF). This indicates that HNT is a potential material in heat transfer applications.

Highlights

With the quick increase of the global population and the development of industries, the demands for resources have grown significantly [1]
The performance of pool boiling heat transfer (PBHT) is experimentally examined by using four different dilute concentrations (0.01%, 0.05%, 0.1%, and 0.5%) of Halloysite nanotube (HNT) based DI nanofluid with the aid of a horizontal copper tube as a heating element
Before the pool boiling test, the dry nanopowder was first characterized by various characterization techniques i.e., FTIR, Raman spectroscopy, scanning electron microscope (SEM), and TG/DTA to investigate the morphology and structure of the HNT powders

Summary

Introduction

With the quick increase of the global population and the development of industries, the demands for resources have grown significantly [1]. More efficacious and beneficial energy usage and administration are needed [2] Another reason comes from the ever-increasing rates of heat emission at both macro- (e.g., car engines) and micro-level (e.g., chips in computer and mobile phones). The cooling by using two phase pool boiling processes is an essential matter in the industrial sector due to the urgent need for miniaturization in one hand and increasing the performance improvement of such heat exchange systems in another hand. Utilizing nanoparticles to make suspension has been an idea for many years These fluids are called nanofluids with higher thermal properties than conventional fluids [3]. Many studies on their HT have been performed [4,5,6,7,8]

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Conclusion