An investigation of heat transfer enhancement in nanofluids containing core and shell nanoparticles.

Nanofluid;Core and shell;Nanoparticle;Carbon coated

Cory Adam Milligan

University:University of Louisville

Department:Chemical Engineering

关键词: Nanofluid;    Core and shell;    Nanoparticle;    Carbon coated;   

Others  :  https://ir.library.louisville.edu/cgi/viewcontent.cgi?article=1982&context=etd

美国|英语

来源: The Universite of Louisville's Institutional Repository

【 摘 要 】

The purpose of this research is to determine the differences in heat transfer enhancement of poly alpha olefin oil after the addition of two types of carbon coated nanoparticles, specifically carbon coated cobalt and carbon coated copper nanoparticles. The carbon shell allows for the nanoparticles to be homogenously dispersed in the oil and remain stable throughout the experimental procedure. The nanofluids were prepared in concentrations of 0.5, 1.0, and 1.5 wt%. A constant surface heat flux testing rig is used to determine the heat transfer coefficients of the base fluids and the nanofluids. Inlet temperatures to the heat transfer section of the rig and flow rate of the fluid are varied to allow analysis of the impact of fluid temperature and Reynolds number. Testing occurred at temperatures of 50, 65, and 90 oC and fluid flow rates of 10 to 100 mL/s. The carbon coated copper nanoparticles showed the largest heat transfer enhancement at a fluid temperature of 65oC and at a loading concentration of 1.0 wt%. In general heat transfer enhancement decreased as both particle concentration and fluid temperature increased. The carbon coated cobalt nanoparticles exhibited the largest heat transfer enhancement at a fluid temperature of 90 oC and a particle concentration of 1.5 wt%. Heat transfer enhancement generally increased as both temperature and particle concentration increased. Overall heat transfer enhancement by the carbon coated copper nanoparticles was larger than the enhancement provided by the carbon coated cobalt nanoparticles at the same flow rate, temperature, and concentration. This is attributed to the higher thermal conductivity of copper metal.