Analysis of parallel flow heat exchanger using SiO₂ nanofluids in the laminar flow region

Abstract

Convective and overall heat transfer coefficients of SiO2 nanofluid flowing in a concentric DTHE are determined experimentally. The tests are carried out in the 800<Re<1900 range using SiO2/22nm nanofluids prepared in 0.2, 0.6 and 1.0% volume concentrations in 30:70 ratio glycerol-water mixture base liquid. The thermal and physical properties of silica nanofluids are determined in the range of 20-80°C. Viscosity, thermal conductivity, and density of nanofluids increased with particle concentration whereas specific heat decreased. Thermal conductivity and specific heat of nanofluids increased with temperature while viscosity and density decreased. Heat transfer experiments are conducted using nanofluids at a bulk temperature of 35°C in a laminar developing flow region. Overall heat transfer coefficient and convective HTC of 1.0% silica nanofluids are increased by 21.2 and 36.3% compared to base liquid.

Heat Transfer Enhancement in the Microscale: Optimization of Fluid Flow

“…As shown in Figure 3 , the viscosity increased as the concentration was increased from 0.05% to 1.0%. Lahari et al [ 32 ] studied the effect of the concentration of SiO 2 nanoparticles in a 70:30 water-glycerol base fluid at temperatures between 20 °C to 80 °C. The viscosity of the nanofluid with concentrations of 0.2%, 0.6%, and 1.0% was found to increase over the entire tested temperature range as the concentration increased.…”

“…The viscosity of the nanofluid with concentrations of 0.2%, 0.6%, and 1.0% was found to increase over the entire tested temperature range as the concentration increased. At 60 °C, the average viscosity of the nanofluid when compared to the base fluid as measured alone increased by 9.3%, 22.8%, 31.8% for the concentrations of 0.2%, 0.6%, and 1.0%, respectively [ 32 ], as shown in Figure 3 .…”

“… Nanofluid viscosity as a function of concentration for various nanofluids, including Al 2 O 3 in water at 21.7 °C [ 30 ], CuO in 80:20 water-ethylene glycol (EG)at 30 °C [ 31 ], and SiO 2 in 70:30 water-glycerol at 60 °C [ 32 ]. …”