Experimental investigation on heat transfer and pressure drop characteristics in a smooth tube with different twisted tape inserts

摘要

Experiments are performed to investigate the impact of inserts (TTI, TBI, and TBHI) accompanied by different twist ratios (ie, y/w=3.69, 4.39, and 5.25) with uniform heat flux condition to study the performance characteristics of pressure drop, rate of heat flow, and heat transfer enhancement. Experiments were carried out on different twisted tape inserts in a turbulent flow regime by choosing suitable Reynolds number between 3100 and 39000. A plain tube is tested and compared with the empirical correlations and are found to be in good agreement with the experimental data. In the case of twisted tape inserts stronger swirl flow is observed along the length of the tube. The variation of reduction in pressure along the length of tube and heat flux in the form of the friction factor and Nusselt number are represented graphically. Thermal performance factor tends to increase with a decrease in the taper twist ratio. The maximum enhancement in Nusselt number and friction factor was found to be in the case of TBI and TBHI. Experimental results are justified and are found to be reliable and accurate with the analytical results, with ±5% and ±4.2% deviation for Dittus-Boelter and Petukhov correlation in the case of Nusselt number and ±7.2% deviation, respectively, for loss in the friction.