CFD investigation of the impacts of variation in geometry of twisted tape on heat transfer and flow characteristics of water in tubes

In this research paper, the influence of variations in geometry of tape insert on thermal performance and flow characteristics of water inside tubes is investigated by means of computational fluid dynamics (CFD). The tape considered is alternate-axis triangular cut twisted tape. The perimeter of the cuts on the tape, the pitch of the tape and the width of the tape were varied. Turbulent flow is considered and uniform heat flux is imposed on the walls of the tubes. The RNG turbulence model is selected for the simulations and RANS equations are applied to render the Navier-Stokes equations tractable. The findings of the investigations indicated that the thermal performance of all the tubes fitted with twisted tape is better than that of the tube without twisted tape, and also that the performance is influenced by the geometry of the twisted tape. In particular, the thermal performance diminishes as the tape pitch increases but it is augmented by an increase in the size of the cuts on the tape and an increase in the width of the tape