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

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 d(p), nanofluids volume fraction phi and also the heat transfer coefficient, thermal property. Average amount of entropy generation S-a and maximum local temperature of wall T-max 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 S-a, which also as the result of rising phi, and S-a maximum reduction is about 24.7%. T-max considerably declines by using nanofluids and enhanced by a rising phi. Also, CuO-water nanofluid has a better effect on heat transfer and flow characteristics than the other nanofluids.