EXPERIMENTAL INVESTIGATION OF FRICTION FACTOR AND HEAT TRANSFER ENHANCEMENT USING CIRCULAR PERFORATED TWISTED TAPE INSERTS IN HEAT EXCHANGERS

Passive approaches, like utilizing perforated twisted tape (TT) inserts, can be powerful tools for enhancing heat transfer within heat exchanger tubes. These inserts create turbulence in the flow without requiring an external power source, making them a compact and cost-effective solution. The perforations in the TT further promote mixing and heat exchange between the fluid and the tube wall. Using data from experiments, this work examines and calculates the impact of a thermal efficiency factor, resistance factor, and heat transfer of a square perforated TT insert. The perforation index (pi) and diameter ratios [(dr = d/d = 0.5, 0.65, and 0.8) = ap/at = 8%, 16%, and 24%] are the parameters of the experiment. Water is used as the working fluid, and testing is done at Reynolds numbers (Re) between 6000 and 27,000, which indicate turbulent flow. The experiment is conducted in a heat interchanger tube using a pierced square tape insert to disrupt the surface and core fluids and promote heat transmission. It has been noted that heat transfers and resistance factors decrease with the increase in thermal efficiency factor. When dr = 0.65 and pi = 8%, heat transmission is around 2.6 times more than that of a conventional tube heat interchanger. The lowest resistance factor was found in the lower Re range, and it was about 2.9 times enhanced compared to a standard heat tube. Experimental data shows that pi = 24% and dr = 0.65 provide the best results over the whole range of flow and geometrical parameters, with a thermal efficiency factor 1.49 times that of a standard tube heat interchanger.