W-Cut Twisted Tape's Effect on the Thermal Performance of a Double Pipe Heat Exchanger : A Numerical Study

A numerical investigation has been performed for double pipe heat exchanger to enhance heat transfer rate and thermal performance factor using W- cut twisted tape. W-cut twisted tape with depth to width ratio (viz. depth of W-cut to width of the twisted tape) of 0.2 - 0.6 has been taken for study. Realizable k-ε turbulence model has been used to determine heat transfer rate in the turbulent zone. Swirl flow analysis shows that flow is divided into two regions; one is near the wall and the other away from the wall. A linear increment in heat transfer rate has been observed relative to Reynolds number. Maximum enhancement in heat transfer rate has been observed at Reynolds number of 15300. The friction factor decreases with increasing Reynolds number but drastically increases with the employing of W-cut twisted tape. An increment in the thermal performance factor has been observed by increasing the depth of cut. The maximum thermal performance factor was observed at a lower Reynolds number. Comparison of thermal performance factor with previous studies has been done and it was observed that present studies have better thermal performance factor relative to other inserts