Abstract
The effect of using innovative turbulator geometry, such as semi-circular and teardrop-shaped turbulators, on heat transfer and pressure drop has been studied for the first time in this study. To this end, eight different geometries have been considered for turbulator in a tube with constant surface temperature. Then, some tests have been performed for different hot water flow rates (mh˙) in the range of 0.044–0.099 kg/s. Also, the optimization was performed using the thermal enhancement factor (TEF) and the net profit of unit transferred heat load (ηp). These kind of turbulators have a major impact on heat transfer and friction factor, according to the findings. The maximum heat transfer values for semi-circular and teardrop-shaped turbulators were respectively 257% and 298% higher than that of the plain tube. Base on the results, a tube with teardrop-shaped inserts (case C) is the optimum case.