Experimental Analysis of Heat Transfer in a Triple Tube Heat Exchanger with Spring Turbulator Using CuO/Water Nanofluid

An Experiment has been performed to find out effect of coiled spring turbulators on the heat transfer and pressure drop in a triple tube heat exchanger using water and CuO/water (0.8%vol/vol) as working media. Two spring turbulators having pitch 5 mm and 10 mm with a common wire diameter
 of 1 mm are being used. The experiment was carried out under turbulent flow at different Reynolds numbers varying between 4000 to 16,000. In this experiment, the variation in the rate of heat transfer and friction factor have been analyzed for parallel and counter flow arrangements. The combination
 of the lower-pitched insert with CuO attained the maximum heat transfer increment in the counter flow pattern. For counter flow arrangement, augmentation in Nusselt number for a triple tube with lower spring pitch with CuO nanofluid is 63.33%, which is higher in comparison to the plain triple
 tube with water as working fluid. The maximum thermal performance value is observed for plain tube with CuO nanofluid having the value 1.04 at Reynolds number of 4000.