Enhancement of Thermo-Hydraulic Performance using Water-Based Alumina Nanofluids: A Numerical Investigation

Abstract

This study investigates the heat transfer and fluid flow characteristics of pure water passing through a double tube heat exchanger (DTHX). Computational fluid dynamics (CFD) simulations were conducted using ANSYS-FLUENT 22 R1 software. Mathematical models and thermophysical properties of nanofluids and water from existing literature were employed. The comparison focused on pure water and 1% Al2O3/H2O nanofluids. Various operating variables such as Reynolds number and temperature were considered across the inner and outer tubes. The Reynolds number ranged from 2500 to 5500 at 80°C for the inner tube and 2500 at 15°C for the outer tube. Key findings include a 7.69% increase in friction factor for 1% Al2O3/H2O compared to pure water and a 16% increase compared to the Gnielinski correlation at a Reynolds number of 2500. The Nusselt number (Nu) exhibited a 98.42% increase compared to the Gnielinski correlation at a Reynolds number of 5500 and a 39% increase compared to pure water at the same Reynolds number. Heat transfer coefficients (hi) were found to increase by 9.52% compared to pure water and 12% compared to the correlation in existing literature.