Numerical simulation of nanofluid application in a horizontal mesh heat pipe with multiple heat sources: A smart fluid for high efficiency thermal system

Abstract

A numerical study is carried out to investigate the effects of aqueous Al2O3 nanofluids on the hydrothermal performance of a cylindrical heat pipe with discrete heat sources (evaporators), as high efficiency heat exchanger. The effects of heat load (Q = 14, 28, 56 and 112 W) and nanoparticle volume fraction (φ = 0, 2.5, 5 and 0.075%) on the temperature and velocity fields, pressure drop and thermal performance of heat pipe are investigated. A more uniform wall temperature can be obtained as base fluid is replaced by nanofluid. Moreover, the higher impact of nanoparticle on the wall temperature reduction is found on the heat sources where the highest values of temperature occur and hence more heat should be removed. This useful feature of nanofluid indicates its potential as smart fluid in heat pipes. The values of velocity and pressure drop in wick structure decrease and increase, respectively, as particle volume fraction increases. The influence of nanoparticles on both thermal and hydraulic performances of heat pipe become more pronounced as porosity of wick structure and particle size, respectively, increases and decreases. Finally, the thermal-hydraulic performance of heat pipe is analyzed. It is found that the best performance occurs at φ = 5% and Q = 112 W.