Effects of Nano Particles Attached onto a Heat Transfer Surface in the Thermal-Hydraulic System

Abstract

This work experimentally explored the influence of nano-fouling, and it was also compared and analyzed CHF, flow boiling heat transfer coefficient, contact angle, and surface roughness. The working fluids in this study were used as purewater and a 0.01 vol% oxidized MWCNT nanofluid. The flow velocity conditions are established at 0.5, 1.0, and 1.5 m/s. Also, the nanoparticles of oxidized graphene were deposited on a heat transfer surface, and artificial spray coating times for nano-fouling are established at 0, 120, 180, and 240 sec. As the results, it was found that the superheated temperature to the CHF extremely increased in case of nano-fouling, it is caused by physical damage of heat transfer system. The flow boiling heat transfer coefficient in an oxidized graphene nanofluid increased up to 24.29% without any treatment on the heat transfer surface, but the coefficient in case of nano-fouling decreased down to 16.26% more than in the purewater.