Convective Heat Transfer And Fluid Dynamic Characteristics Of Sio_2-ethylene Glycol/water Nanofluid

摘要

Nanofiuids comprised of silicon dioxide (SiO_2) nanopartides suspended in a 60∶40 (% by weight) ethylene glycol and water (EGlwater) mixture were investigated for their heat transfer and fluid dynamic performance. First, the rheological properties of different volume parents of SiO_2 nanofiuids were investigated at varying temperatures. The effect of panicle diameter (20 nm, 50 nm, 100 nm) on the viscosity of the fluid was investigated. Subsequent experiments were performed to investigate the convective heat transfer enhancement of nanofiuids in the turbulent regime by using the viscosity values measured. The experimental system was first tested with EGlwater mixture to establish agreement with the Dittus-Boelter equation for Nusselt number and with Blas'tus equation for friction factor. The increase in heat transfer coefficient due to nanofiuids for various volume concentrations has been presented. Pressure loss was observed to increase with nanopartkie volume concentration, It was observed that an increase in particle diameter increased the heat transfer coefficient. Typical percentage increases of heat transfer coefficient and pressure loss at fixed Reynolds number are presented.