Numerical Study on the Heat Transfer Characteristics of Cu-Water and TiO2-Water Nanofluid in a Circular Horizontal Tube

A numerical simulation of convective heat transfer coefficient (hconv) was studied with Cu-Water and TiO2-Water nanofluids flowing through a circular tube subjected to uniform wall flux boundary conditions under laminar turbulent regimes. Four different concentrations (ɸ = 0.5, 1, 1.5 2%) were used for the analysis Reynolds number (Re) varied from (500 2000) flow regime (5000 20,000). The dependence hconv on Re ɸ investigated using single-phase Newtonian approach. In comparison base fluid, average enhancements 10.4% 7.3% noted, respectively, maximum concentration 2000 TiO2—water in regime. For same (Re 20,000), noted be 14.6% 13.2% both nanofluids, respectively. random motion (Brownian motion) diffusion (thermophoresis) by nanosized particles are two major slip mechanisms that have more influence enhancement hconv. addition, Nusselt (Nu) present work validated water Shah Dittus Boelter equation found good agreement