Experimental investigation of enhancing influence of Al2O3 nanoparticles on the convective heat transfer in a tube equipped with twisted tape inserts

Abstract

In this study, the heat transfer rate of Al2O3-water nanofluid-flow in a tube with twisted tape inserts is experimentally examined. The twisted tape insert can cause a swirling region in the fluid-flow which will enhance the heat transfer coefficient. On the other hand, the twisted tape inserts have a great influence on the pressure drop. It is known that nanoparticles and twisted tape inserts may both increase the heat transfer rate of the fluid. Thus, in this study, it is tried to demonstrate the combined effect of both phenomena, experimentally. In this way, the Al2O3-water nanofluid is used as the carrier liquid in a tube equipped with various twisted tape inserts of different pitches and twist ratios. Moreover, the influence of nanoparticles? volume fractions was studied in the turbulent regime of a tube with the constant temperature boundary condition.