The influence of different twisted tape inserts configurations on thermo-hydraulic performance and enhancement of heat transfer in the 3D circular tube

Numerical simulation was performed to analyze the behavior of a flow field, characteristic of pressure drop, and hydraulic thermal performance. Moreover, influences of different twisted tape geometric parameters, including three twisted tape inserts (NTTI) 1, 3 and 5. Also, six different twisted turns (NTT) were comparably quantitative and qualitative studied using various important parameters, including static pressure, dynamic pressure, and velocity magnitude, respectively. The results revealed that the value of pressure drop between each cross section in the pipe decreases as pipe length increases. When the NTTIs increases that leads to a pressure difference also increasing as compared to the smooth pipe. It is found that inserting twisted tape in the pipe leads causes considerably high resistance in the flow, then leads to increase the pressure difference. In addition, the results show that existence of the twisted tapes inside the pipe can create more vortex motion (swirl flows) that leads to formation of different radial velocities. Also, the PEF factor decreases as the Re increases. The comparison results for the numerical and experimental indicate that a good agreement of the average deviation for f (friction factor) and Nu is around 6.5% and 7%. The minimum Nu number value was 10 for NTT1 at Re number of 900 and the higher value was 50 at Re of 14,000. The PEF is more than 1.6 for NTT6 configuration. The results indicate that the temperature difference increases up to 38.1%, 46.11% and 50.52% with increasing the NTTI from 1 to 5, respectively, as compared to the temperature difference in a smooth pipe.