| Popis: |
In this numerical study, heat transfer characteristics and hydrodynamical analysis have been performed for a circular tube inserted with twisted tape, which has different twisted pitch ratios (TPR=0, 50, 100, and 200). As a working fluid Al2O3/water nanofluid is used which has different volumetric concentrations (0.0≤φ≤3.0 vol. %). The numerical analysis has been carried out under the constant wall heat flux (q′′) of 4357 W/m2 for laminar flow ranging the Reynolds (Re) number from 1000 to 2000. According to numerical results, the highest average Nusselt number (Nu) and average Darcy friction factor (ff) have realized in twisted pitch ratio (TPR) 50. The reason is that when the twisted pitch ratio gradually decreases, stronger secondary flows and a higher velocity can be obtained. When compared with water, the highest Nu for TPR=50 has been obtained at φ=3.0 vol. % concentration as 61.15%. Also, when compared with TPR=0, the highest thermal performance enhancement (TPE) was realized at φ=3.0 vol. % concentration and Re=2000 conditions as 61.15% for TPR=50. Keywords: CFD Convective heat transfer Laminar flow Al2O3/water Twisted tape |
