COMPUTATIONAL ANALYSIS OF HEAT TRANSFER ENHANCEMENT IN A CIRCULAR TUBE USING SEMICIRCULAR NOTCHED ROTARY TWISTED TAPE INSERTS

Heat transfer enhancement of air flow using twisted tape inserts in a circular copper tube have been investigated under turbulent flow regime. A simulation technique is employed to simulate the swirling flow of twisted tape insert with and without semi-circularnotch with three different pitch ratios (P/w = 3,4 and 5). The Reynolds number is varied in the range of 25000 to 35000. The heat transfer enhancement represented by a Nusselt number (Nu) in turbulent flow regime is investigated by using CFD (Ansys 16.0 FLUENT) to investigate the physical behaviourof the thermal and fluid flows under uniform heat-flux condition.Results shows that the semi-circularnotch twisted tape inserts develops a strong turbulence flow within fluid flow which increases heat transfer rate. The use of semi-circularnotch twisted tape lead to a considerable increase in heat transfer and pressure drop in comparison with the plane tube. The heat transfer rate increases with increase in Reynolds number and decrease in pitch ratio