ENHANCEMENT OF HEAT TRANSFER USING EXTERNALLY FINNED TUBE WITH CUO-ZNO/WATER HYBRID NANOFLUID IN A SHELL AND TUBE HEAT EXCHANGER

ABSTRACT: Shell-and-tube heat exchangers find extensive application in the industrial heating and cooling processes which have led to countless attempts to modify their thermal performance. This is a numerical investigation of heat transfer enhancement in a shell-and-tube heat exchanger with externally spiral-finned copper tubes using CuO–ZnO/water hybrid nanofluid as the working fluid. A three-dimensional steady-state computational model utilizing ANSYS Fluent 22 R1 was created to investigate the thermo-hydraulic characteristics of clean water and hybrid nanofluids containing nanoparticle volume fractions of 1% and 5%. Hot fluid at 353 K enters the shell side with velocity from 0.5 to 1.7 m/s, and cold water passes through seven finned tubes at 300 K under counter-flow condition. The results confirm that adding CuO–ZnO nanoparticles improves the heat transfer performance as compared to pure water. Outlet temperature, Nusselt number, heat transfer rate and convective heat transfer coefficient are decreased with the rise in LNP concentration. The largest enhancement is achieved by the 5% CuO–ZnO/water hybrid nanofluid due to its higher effective thermal conductivity, stronger micro-convection and better thermal boundary-layer disruption. Temperature contour analysis additionally corroborates uniform thermal distribution throughout the surface the wall temperatures decrease as volumetric concentration increases.