Experimental and numerical assessment on hydrothermal behaviour of MgO-Fe3O4/H2O hybrid nano-fluid

Abstract

This study presents an experimental and numerical investigation of heat transfer enhancement inside plain and wavy tubes using a new type of hybrid Nano-fluid (50% Fe3O4+ 50% MgO/H2O) with volume concentrations (φ = 0.5%, 1%, and 2%) under fully developed turbulent flow and constant heat flux. The experimental Apparatus consists of the hybrid Nano-fluid tank, chiller system, four control valves, digital manometer, temperature controller, flow meter sensor, pump, and a transparency piping system to study the heat transfer improvement. All the tests were conducted with constant heat flux (18,189 W/m2) and Reynolds number (Re = 3,916 – 31,331). The experimental investigation also includes measurements and preparation of the considered hybrid Nano-fluid. Numerical simulation has been carried out employing Workbench [ANSYS FLUENT package-(19.3)] utilizing multiphase approaches; single-phase and mixture model to analyze flow field, migration of nanoparticles volume fraction effect, and heat transfer. The comparison between experimental and numerical outcomes revealed good agreement. The results demonstrated that increasing Reynolds numbers and volume fractions lead to a lower friction factor and a more enhancement in heat transfer (Nusselt number) and performance evaluation criteria (PEC) than the conventional base fluid along both considered tubes. The highest Nusselt number was observed at 2% of (Fe3O4−MgO/H2O) hybrid Nano-fluid in both tubes. However, the results were higher for a wavy tube than the plain one, as the maximum improvement in heat transfer was (135.2)% and (166.5)% with plain and wavy tubes, respectively. Moreover, new correlations were developed for a particular Fe3O4−MgO/H2O hybrid Nano-fluid volume fraction.