Effects of Double V Cuts in Perforated Twisted Tape Insert: An Experimental Study

The thermal performance of heat exchanger is considerably enhanced by the use of inserts. Twisted tape inserts are known for producing large heat transfer enhancements at the expense of fairly large friction penalty. With the objective to explore the effect of twisted tape with perforations and V cuts, the present study investigates the thermo-hydraulic performance of solid twisted tape, perforated twisted tape, and perforated twisted tape with double V cuts for the Reynolds number range of 2000-25000. During the experiments, the twist ratio of tapes is varied in the range of 2-6, while the depth ratio and width ratio of V cuts for perforated twisted tape with double V cuts are varied in the range of 0.2-0.27. The maximum enhancements in Nusselt number and friction factor were found to be 3.5 and 9.63, respectively, corresponding to the perforated twisted tape with double V cuts having V cut depth ratio and width ratio of 0.27 and twist ratio of 2.