Semnan University Press Journal of Heat and Mass Transfer Research 2345-508X 1 2 2014 10 01 The effect of Geometrical parameters on heat transfer coefficient in helical double tube exchangers 75 82 182 10.22075/jhmtr.2014.182 EN Seyed Faramarz Ranjbar Mechanical Engineering Faculty, University of Tabriz, Tabriz, Iran Mir Hatef Seyyedvalilu Mechanical Engineering Faculty, University of Tabriz, Tabriz, Iran Journal Article 2013 10 31 Helical coil heat exchangers are widely used in industrial applications ranging from<br />cryogenic processes, air-conditioning, and nuclear reactors to waste heat recovery due to<br />their compact size and high heat transfer coefficient. In this kind of heat exchangers, flow<br />and heat transfer are complicated. This paper reports a numerical investigation of the<br />influence of different parameters such as coil radius, coil pitch and diameter of tube<br />on the characteristics of heat transfer in helical double tube heat exchangers using<br />the well-known Fluent CFD software. Modeling of the study was implemented based on<br />principles of heat transfer, fluid mechanics, and thermodynamics. By imposing boundary<br />conditions and selecting of an appropriate grid, whereby the results are independent of<br />meshing, the obtained results were compared and validated with existing experimental<br />results in the open literature. The results indicate that heat transfer augments by increasing<br />of the inner Dean number, inner tube diameter, curvature ratio, and by the reduction of the<br />pitch of the heat exchanger coil. https://jhmtr.semnan.ac.ir/article_182_7553a3f224c4efe7d924b793aadafbac.pdf