Nemati, HossainArdekani, Mohammad MoghimiCemal Benim, AliMeyer, Josua P.2023-11-142023-11-142022Hossain Nemati, Mohammad Moghimi Ardekani, Ali Cemal Benim & Josua Meyer (2022) Optimization of Horizontal Annular Finned Tube Under Natural Convection Heat Transfer, Heat Transfer Engineering, 43:17, 1451-1463, DOI: 10.1080/01457632.2021.1975998.0145-7632 (print)1521-0537 (online)10.1080/01457632.2021.1975998http://hdl.handle.net/2263/93296Free convection heat transfer over annular finned tubes was studied numerically for more than 60 different cases and verified against two experimental works. In addition, the effect of fin spacing on heat transfer was investigated. As a result, a correlation was proposed to estimate Nusselt number as a function of Rayleigh number. Moreover, it was shown that there was an optimum fin spacing for which the total heat transfer was maximized. Based on the proposed equation, an expression for optimum fin spacing was derived, which proved that the optimum Nusselt number was 0.9035. The presented equation for optimum fin spacing was a general equation in so far that it could also be used to find the optimum spacing between a series of circular disks by letting the tube diameter in the equation be zero. Moreover, a good agreement was observed between the derived equation for optimum fin spacing and the results of the scale analysis method.en© 2022 Taylor & Francis Group, LLC. This is an electronic version of an article published in Heat Transfer Engineering, vol. 43, no.17 , pp. 1451-1463, 2022. doi : 10.1080/01457632.2021.1975998. Heat Transfer Engineering is available online at : http://www.tandfonline.comloi/uhte20.Convection heat transferAnnular finned tubeEngineering, built environment and information technology articles SDG-04SDG-04: Quality educationEngineering, built environment and information technology articles SDG-07SDG-07: Affordable and clean energyEngineering, built environment and information technology articles SDG-09SDG-09: Industry, innovation and infrastructureEngineering, built environment and information technology articles SDG-13SDG-13: Climate actionPreprint Article