Numerical study on heat transfer and nanofluid flow in pipes fitted with different dimpled spiral center plate

Abstract

This research presents a numerical study on heat transfer and flow characteristics for two pipe fitted by two different dimpled spiral center plate by utilizing Al2O3, CuO and TiO2 nanofluids as cooling fluids. Considering the effect of dimples arrangement, nanoparticle diameter dp, nanofluids volume fraction φ and also the heat transfer coefficient, thermal property. Average amount of entropy generation Sa and maximum local temperature of wall Tmax were discussed. Results demonstrate that the in-line arrangement geometry behaves better in compare to the geometry with the staggered arrangement. 47.3% is the maximum enhancement of convection heat transfer for the in-line arrangement in compare with the smooth spiral central plate with base flow. Using nanofluids improved the wall temperature distribution, and using nanofluid caused great improvement in thermal conductivity with a little raise in dynamic viscosity. Using nanofluids caused a considerable decrease in Sa, which also as the result of rising φ, and Sa maximum reduction is about 24.7%. Tmax considerably declines by using nanofluids and enhanced by a rising φ. Also, CuO–water nanofluid has a better effect on heat transfer and flow characteristics than the other nanofluids.