STUDY OF CONVECTIVE HEAT TRANSFER FOR TURBULENT FLOW OF NANOFLUIDS THROUGH CORRUGATED CHANNELS

摘要

Numerical study of turbulent heat transfer of nanofluid through a corrugated channel is presented. The finite volume method is used to solve the transport equation for the momentum, energy and turbulence quantities adopting a single phase approach. The corrugated channels are sine-shaped, V-shaped and rectangular shaped with amplitude (a/H) and wave length (λ/H) of 0.15 and 1 respectively. Three different nano-particles such as aluminum oxide (Al_2O_3), Copper (Cu) and titanium dioxide (TiO_2) with different volume fraction (1%, 3% and 5%) using water as the base fluid are analyzed for a range of Reynolds number from 2000 to 14,000 with constant heat flux at the corrugated walls. Realizable k-ε turbulence model with enhanced wall treatment is considered. For all three geometries, average Nusselt number for the corrugated section is obtained. The result reveals that increasing the Reynolds number and volume fraction of nanoparticle in the base fluid has an effect of increasing the heat transfer rate. The sine shaped channel gives a better heat transfer enhancement compared to other two geometries up to Re = 8200 for 3% volume fraction of Al_2O_3-water nanofluid. At Reynolds number higher than this, rectangular shaped corrugated channel gives better heat transfer rate. Among the nano-particles, Al_2O_3 gives a higher heat transfer rate in all three corrugated channels. The enhancement of heat transfer is about 10.5% to 50.15% compared to water for the flow of Al_2O_3-water nanofluid through sine wave channel depending on the Reynolds number and volume fraction.