Enhancement of boiling heat transfer with nanofluids

• Main Author: Veerappan Thilakavathi
• Other Authors: Leong Kai Choong
• Format: Final Year Project
• Language: English
• Published: 2012
• Subjects: DRNTU::Engineering::Nanotechnology
• Online Access: http://hdl.handle.net/10356/50026
• Institution: Nanyang Technological University

Nanofluid is a new class of heat transfer fluids and also known as a smart fluid, where heat transfer can be reduced or enhanced at will. In this report, enhancement of nanofluids will be analysed through pool boiling method. It is made by dispersing nanoparticles into conventional heat transfer solution such as distilled water, ethylene glycol and other type of alcohols. This report describes an experimental study on enhancing boiling heat transfer of nanofluid; Al2O3 particles dispersed in 50%-50% ethanol/de-ionized water. Apart from that, this report focuses on presenting the heat transfer properties of nanofluids with various concentrations and nanoparticle sizes. Nanofluid was made by two-step process. Pool boiling was conducted in the experimental facility [copper test chamber with external condensation unit] designed by the author. Thermal conductivity tests were performed by using a commercial Lambda System. Two concentrations of 0.01% and 0.05% with 200 nm size of Al2O3 particles and two concentrations of 0.01% with 150 nm and 200 nm sizes of Al2O3 particles were used to analyse these two experiments. The results show heat flux enhancement of 5.4% when there is particle loading and increases when the concentration of particles increases. Particle loading also proved 75% enhancement in the thermal conductivity test. Another important parameter tested was nanoparticle size. The effect of the particle size proved an inverse relation for both tests- particle size decreases, the heat flux enhances and thermal conductivity also enhances to considerable percentage value.