Performance intensification of turbulent flow through heat exchanger tube using double V-cut twisted tape inserts

Abstract

This paper aims to present a numerical model for heat transfer intensification in a heat exchanger tube equipped with novel double V-cut twisted tape. The effects of different cut ratios (0.6 < b/c<1.8) on the turbulent flow characteristics and thermal performance of the system are investigated over the Reynolds number range from 5000 to 15,000. The accuracy of (RNG) k-ε turbulence model used in the present study is validated by comparing with experimental results. The tube equipped with double V-cut twisted tape shows improved thermal performance in comparison with conventional twisted tape. This improvement is due to the additional vortex flow induced by the V-cuts which leads to more effective thermal boundary layer disruption and thus intensifies the heat transfer rate. There are 48.0%, 64.3%, 86.0%, and 117.4% enhancement in the heat transfer rate by using double V-cut twisted tape with b/c = 0.6, 1, 1.4, 1.8 in comparison with the conventional twisted tape. The maximum thermal performance factor of 1.83 is obtained by using the heat exchanger tube with the double V-cut twisted-tape with b/c = 1.8 and y/w = 3 at the Reynolds number of 5000.