The effect of different twisted tape inserts configurations on fluid flow characteristics, pressure drop, thermo-hydraulic performance and heat transfer enhancement in the 3D circular tube

The thermal-hydraulic performance of the circular pipe heat exchanger is determined by numerical simulations of the flow field and pressure drop inside the pipe. Initially, a three-dimensional numerical model is validated using experimental results. Turbulent flows are solved using the governing, momentum and energy equations. With constant heat flux as the boundary condition, the (RNG) k-ω turbulent model predicts flow structures. Different twisted tape inserts (NTTI) (1, 3 and 5) are considered when analysing the influence of different twisted tape geometric parameters. A variety of important parameters are compared quantitatively and qualitatively using six different twisted turns (NTT): static pressure, velocity magnitude, vorticity and static temperature. Twisted tape inserts in pipes can increase flow resistance, which leads to an increase in pressure difference. Furthermore, thetwisted tapes inside the pipe caused more vortex motion (swirl flows), which resulted in different radial velocities. As compared to the temperature difference in a smooth pipe, the numerical results show that the temperature difference increases up to 38.1%, 46.11% and 50.52% when the NTTI is increased from 1 to 5.