An Experimental and Numerical Study of Convective Boiling of Nanoemulsion Inside Mini-Channels Heat Exchanger

Abstract

In this paper, both experimental and numerical studies have been performed on the convective boiling heat transfer of the Ethanol-in-Polyalphaolefin (PAO) Nanoemulsions inside a heat exchanger of twelve 1mm diameter mini-channels that was subjected to a uniform heat flux at its outer surface. The heat transfer characteristics and the pressure drop of the Ethanol/PAO nanoemulsion was studied experimentally, meanwhile, the volume of fraction (VOF) model with Pressure-Velocity coupling based Semi Implicit Method for Pressure Linked Equations (SIMPLE) iterative algorithm is employed to simulate the same experimental conditions numeircally. The results reveal that the convective boiling heat transfer coefficient of the nanoemulsion can be greatly enhanced upon the nucleation of ethanol nanodroplets inside, in which a maximum 50% enhancement compared to pure PAO base fluid can be achieved under current test conditions. However, the thermal conductivity and viscosity of the nanoemulsions has an insignificant effect on convective boiling heat transfer coefficient based on the experimental results. The ANSYS FLUENT simulation results also agree well with the experimental data. The Ethanol-in-PAO nanoemulsion could function as a good alternative conventional working fluid in two phase heat transfer applications.

Experimental Approaches to Measurement of Vapor Quality of Two-Phase Flow Boiling

“…Although many experimental studies have been conducted to date to investigate the impact of local vapor quality on boiling heat transfer performance, majority of these studies have taken the similar approach to measure local vapor quality Experimental Approaches to Measurement of Vapor Quality of Two-Phase Flow Boiling DOI: http://dx.doi.org /10.5772/intechopen.94473 only at the outlet of test section mainly under uniform wall heat flux boundary conditions using electrical heating [6][7][8][9][10][11][12]. There are limited studies investigating the effect of local vapor quality for other thermal boundary conditions [13,14], while their techniques to measure local vapor quality are not reported clearly.…”