Effect of Uniformly and Nonuniformly Coated Al2O3 Nanoparticles over Glass Tube Heater on Pool Boiling

Nitin Doifode,Sameer Gajghate,Ashok Pise,Abdul Najim,Anil Acharya

doi:10.1155/2016/8763171

Abstract

Effect of uniformly and nonuniformly coated Al2O3 nanoparticles over plain glass tube heater on pool boiling heat transfer was studied experimentally. A borosilicate glass tube coated with Al2O3 nanoparticle was used as test heater. The boiling behaviour was studied by using high speed camera. Result obtained for pool boiling shows enhancement in heat transfer for nanoparticle coated surface heater and compared with plain glass tube heater. Also heat transfer coefficient for nonuniformly coated nanoparticles was studied and compared with uniformly coated and plain glass tube. Coating effect of nanoparticles over glass tube increases its surface roughness and thereby creates more nucleation sites.

Highlights

Boiling occurs at solid-liquid interface when a liquid is brought into contact with a surface maintained at a temperature sufficiently above saturation temperature of liquid
The boiling process is characterised by the rapid formation of vapour bubbles at solid-liquid interface that detach from the surface when reaching at certain size and attempt to rise to the free surface of liquid
Water was used as working fluid and high speed q = 5000 W/m2 q = 10000 W/m2 q = 15000 W/m2

Summary

Introduction

Boiling occurs at solid-liquid interface when a liquid is brought into contact with a surface maintained at a temperature sufficiently above saturation temperature of liquid. The boiling process is characterised by the rapid formation of vapour bubbles at solid-liquid interface that detach from the surface when reaching at certain size and attempt to rise to the free surface of liquid. Boiling has been found in a wide range of applications such as power generation, refrigeration, air-conditioning, chemical and thermal processes, cooling of electronic components, microfluidic system, thermal control of aerospace station, and material processing. Various techniques for augmentation of boiling heat transfer have been proposed and studied. Typical approaches that have been considered to enhance “Pool” boiling heat transfer in particular include treated surfaces, rough surfaces, mechanical aids, surface vibrations, electrostatic field, additives for fluids (surfactants), and so forth

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Results

Conclusion