Numerical investigation with sensitivity analysis of heat transfer performance in a heat exchanger containing nanofluids

Abstract

The innovative uses of nanofluids in thermal engineering, biomedical engineering, and manufacturing processes have made this field of research interesting on a global scale. In view of such significant applications, the goal of this work is to look into the thermal performance of nanofluid inside a hexagonal heat exchanger. This examines mixed convective phenomena for fluid flow with heat transfer of Titanium Oxide (TiO2) and water (H2O) based nanofluid. A hot cylinder on the left portion and another cold cylinder on the right portion are taken horizontally to form a heat exchanger. All of the surrounding walls are considered adiabatic where a magnetic field is acted on the right walls. The Galerkin weighted residual technique of finite element method is utilized to execute the governing equations numerically. The investigation is carried out for the Reynolds number (Re = 10-200), Richardson number (Ri = 0.01-10), Hartmann number (Ha = 0-100), and nanoparticle volume fraction (ϕ = 0-0.1), which are some relevant parameters. Streamlines, isotherm lines, velocity fields, and average Nusselt numbers (Nuav) are used to depict the collected results. The response surface methodology is used to conduct a sensitivity analysis of independent variables on response function. It is observed that growing value of Re and ϕ strengthen the thermal performance of nanofluid whereas increasing Ha causes it to decrease. When Ha is maintained at 0, the Nuav reaches its maximum values at Re = 200 and ϕ = 0.1. Moreover, ϕ and Re have positive sensitivity to the Nuav while Ha has negative sensitivity. The results of this study may assist engineers and researchers for creating effective mixed convective heat exchangers.