Numerical Investigation on Heat Transfer of CuO-Water Nano-fluid in a circular pipe with twisted tape inserts

Abstract The use of Nano-fluids and twisted tape inserts in circular pipes are the most widely used passive heat transfer improvement techniques. The Nusselt number, friction factor, and thermal performance parameters of a circular pipe containing Nano-fluids and twisted tapes at 180 and 120 degrees are studied numerically in this work. The research yields findings for a strip twist ratio of three and a turbulent flow range of Re 4,000–20,000. The RNG k–ε model is utilized to solve the governing equations and a steady heat flux of 30,000 W/m2 is supplied. The highest simulation findings of Nusselt number for Nano-fluid are 5.25, 9.85, and 12.5% higher in comparison to Gnielinski relations of water for plain tube and twisted tape inserts at 180 and 120 degrees respectively. The thermal performance factor of 1.42 was achieved for Nano-fluid flow in a pipe with a 120o twisted tape insert which yields a significant heat transfer improvement.