Experimental and computational determination of heat transfer, entropy generation and pressure drop under turbulent flow in a tube with fly ash-Cu hybrid nanofluid

The purpose of this research is to study the forced convection heat transfer and flow characteristics of water base fly ash-Cu (80:20% by volume) hybrid nanofluid (HNF) flow through a copper tube under a constant heat flux (CHF) of 7962W/m2 experimentally and numerically. The present work presents results for the concentrations of 0.5–2.0 vol% at a fluid inlet temperature of 30 °C in the flow rate range of 5–16 LPM. HNF stability, thermal conductivity, and viscosity were experimentally analyzed and compared with the established correlations. The maximum augmentation in Nusselt number (Nu) was 57.1% and 8.95% at a concentration of 2.0% relative to water for HNF and fly ash nanofluid (FANF), respectively. The total entropy generation varies inversely with the Reynolds number (Re). The pressure drop (Δp) of HNF is greater than the FANF and water. The development of correlations with experimental data is for determining Nu and friction factors of HNF. Bejan number (Be) of HNF and FANF varies inversely with concentration and Re improvement. The values of thermal performance factor (TPF) enhance with concentration, and a maximum TPF value observed is 1.52 at 2% concentration. The performance of the computational analyses is with ANSYS software gives a reasonable agreement between them.