CFD analysis for the performance improvement of a double pipe heat exchanger with twisted tape having triangular cut

This paper studied the thermal performance of a double pipe heat exchanger using triangular cut twisted tape. The triangular cut twisted tape used in the study has w/W of 0.31, 0.47, and 0.63, respectively. The range of Reynolds number undertaken for studies was in turbulent zone varying from 5500 to 15300. k-epsilon turbulence model has been used for computational studies. It has been found that the effect of twisted tape results in swirl flow in two regions near the tube wall, the twisted tape wall, and in the core region. Due to swirl phenomena, an improvement in fluid mixing was observed with the use of triangular cut twisted tape. The Nusselt number improved by about 2.45 times and the friction factor increased by 9.22 times as compared to plain tubes without twisted tape. The maximum value of 1.21 as thermal performance factor was observed at Reynolds number of 5500.