Keywords: aluminium oxide nanofluids, turbulent forced convection, twisted tape insert, convective heat transfer, heat transfer enhancement, nanofluid pressure drop, nanotechnology, turbulent flow, tubes
Turbulent forced convection of Al2O3 nanofluid in a circular tube with tape inserts at low volume concentration
Convective heat transfer coefficients with Al2O3 nanofluid under turbulent flow in a circular tube fitted with twisted tape insert is estimated. The thermo-physical properties such as thermal conductivity and viscosity are established experimentally in a wide range of volume concentration and validated with values obtained by others. The heat transfer coefficient obtained with Al2O3 nanofluid having volume concentration of 0.02% is 10% higher when compared with water flowing in the tube at Re = 22,000. Tapes of different twist ratios in the range of 5 < H/D < 15 are used as tube inserts to evaluate nanofluid heat transfer and pressure drop. Nanofluid heat transfer coefficient is enhanced by 23% and maximum pressure drop by 1.7 times with tape insert in the range of H/D tested when compared to flow in a plain tube.