Effect of wire coil turbulators on pressure drop and heat transfer augmentation in a circular tube

An experimental investigation is performed for a wire coil turbulators inserted in a tube with constant heat flux condition in a turbulent regime. The effect of wire coil inserts on heat transfer and friction factor are measured experimentally with distilled water as a working fluid at Reynolds numbers ranging from 6000 to 18200. Three wire coils having pitches 10, 22 and 33 mm are introduced. Results shows that the Nusselt number and friction factor values of wire coils are enhanced by 3.75% to 14.54% and 11.4% to 39.22% respectively as compared to plain tube values and maximum for wire coil having 10 mm pitch. From the thermal performance factor it is noticed that the wire coil inserts gives good net energy gain for Reynolds number below 10000.