Numerical investigation of fluid flow and heat transfer characteristics of MWCNT-Al 2 O 3/H 2 O hybrid nanofluid flowing through a novel semi-arc ribbed square duct

Abstract

This study carried CFD analysis to study the fluid flow and heat transfer characteristics of MWCNT- Al 2 O 3 / H 2 O hybrid nanofluid flowing through square duct equipped with novel semi-arc ribs. The turbulent flow simulations are performed at varying Reynolds numbers ( Re ) between 3,000 and 18,000 and nanoparticle volume concentration ( φ ) range of 1–4% for different rib parameters, namely relative stream pitch ratio ( X pr ) range from 2.67 to 3.67, Rib height ratio ( R hr ) range from 0.05 to 0.20, number of ribs ( n ) range from 1 to 4. Different performance indicators, such as Nusselt number ( Nu ), friction factor ( f r ) , and thermal hydraulic performance (THP) was examined to evaluate the system performance. The RNG k ‐ ε model was engaged to simulate turbulent nanofluid flow within the channel under constant temperature condition (T = 300 K). The findings indicated that the development of vortex flow and increased turbulence due to the effects of arcs can improve the heat transfer enhancement. The THP, Nu and f r were found to be highest for R hr = 0.15 , X pr = 3.34 , φ = 4 % , and n = 3 , yields to the best THP at 1.94.