Semnan University Press Journal of Heat and Mass Transfer Research 2345-508X 11 1 2024 06 01 Experimental Study of Heat Transfer Augmentation Characteristics of a Tube Affected by Geometric Parameters of Coiled Spring Inserts 127 138 8699 10.22075/jhmtr.2024.30106.1426 EN Arvind Ashok Kapse Department of Mechanical Engineering, M.V.P.S’s K.B.T. College of Engineering, Nashik, 422013, Maharashtra, India Vinod Chimanrao Shewale Department of Mechanical Engineering, M.V.P.S’s K.B.T. College of Engineering, Nashik, 422013, Maharashtra, India Journal Article 2023 03 05 In the present study, the heat transfer and flow friction characteristics of a circular tube with coiled spring inserts are experimentally reported for a fully developed turbulent flow regime. Experimental investigations were performed in a circular concentric tube in a tube heat exchanger in the Reynolds number (Re) range of 8000–32,000 with water as a working fluid. The average Nusselt number ratio (Nua/Nup) and average friction factor ratio (fa/fp) with and without inserts are reported to be in the range of 1.79–2.79 and 2.44–4.17, respectively, for the tested six geometries of the inserts. The Nusselt number ratio (Nua/Nuc) based on equal pumping power criteria is also reported and found to be in the range of 0.94–1.24. The effects of varying pitch to length of insert ratio (p/l) and diameter of insert to the inner diameter of tube ratio (dc/Di) on heat transfer and pressure drop are reported, and empirical correlation is given for Nusselt number in terms of Reynolds number (Re), pitch to length of insert ratio (p/l), insert diameter to inner diameter of tube ratio (dc/Di), and Prandtl number (Pr). https://jhmtr.semnan.ac.ir/article_8699_eb264570c7b098a9e8009bf3abcb7deb.pdf