Static and dynamic thermal behavior of carbon based nanofluids

Date of Award

2013

Degree Name

M.S. in Mechanical Engineering

Department

Department of Mechanical and Aerospace Engineering

Advisor/Chair

Advisor: Khalid Lafdi

Abstract

Nanofluids are a new class of heat transfer fluids which are engineered by dispersing nanometer-sized solid particles or tubes in conventional heat transfer fluids such as water, ethylene glycol, and engine oil. The first part of this study includes carbon nanotube (CNT)-ethylene glycol (EG) suspension as thermal management fluids. Three types of CNTs with various degrees of crystallinity and surface energy were prepared using heat-treatment temperature. The thermal conductivity of nanofluids tested at varying concentration from 0% to 1.2% using static and dynamic thermal tests. The CNT type and volume concentration were investigated at various shear rates. The thermal resistance of the test suspensions decreased with increasing shear rate. These tests showed that CNT with higher crystallinity and concentration exhibit better thermal performance. However, these CNT tend to break down under high shear. Conversely, CNT with medium crystallinity exhibits the best compromise. The second part of the study includes the formulation of a theoretical model for the effective thermal conductivity of nanofluids. The model is based on a novel point of view regarding the arrangement of nanoparticles in the base fluid. The predictions from the model show a reasonably good agreement with the experimental results.

Keywords

Nanofluids Thermal conductivity, Nanotubes, Carbon, Heat Transmission, Nanofluid; carbon; nanotube; thermal; CNT

Rights Statement

Copyright © 2013, author

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