Amirkabir University of Technology Amirkabir Journal of Mechanical Engineering 2008-6032 52 2 2020 04 20 Experimental Study of Fluid Flow and Heat Transfer of Al2 O3 -Water Nanofluid in Helically Coiled Micro-Finned Tubes Experimental Study of Fluid Flow and Heat Transfer of Al2 O3 -Water Nanofluid in Helically Coiled Micro-Finned Tubes 509 524 2927 10.22060/mej.2018.13989.5773 FA Majid Dastmalchi department of heat and fluid faculty of Mechanical Engineering, University of Kashan, Kashan, Iran Ghanbar Ali Sheikhzadeh Department of Heat and Fluid, Faculty of Mechanical Engineering, University of Kashan, Kashan, Iran 0000-0002-7874-9981 Ali Arefmanesh Department of Heat and Fluid, Faculty of Mechanical Engineering, University of Kashan, Kashan, Iran Journal Article 2018 01 27 In this study, inactive methods of enhancing heat transfer in the shell and tube heat exchangers, such as using smooth and micro-fins helically coiled tubes, and employing nanofluids as the working fluid, are investigated experimentally. A number of experiments are carried out for the flow of the Al2 O3 -water nanofluid in a shell and tube heat exchangers with helically coiled smooth as well as micro-finned tubes, and the pressure drop and the heat transfer coefficient are measured. The experiments are conducted for the Dean number ranging from 500 to 4000, for the fin helix angle between 18 and 25º, and for the nanofluid volume fractions of 0, 0.5 and 1%. The average heat transfer coefficients of the tube side of heat exchangers in each case is calculated using the Wilson plot method. Empirical correlations are proposed for the heat transfer coefficient of the nanofluid following through the tube-side of the heat exchanger in terms of the Dean number, the fin helix angle, the fin height and the volume fraction of the nanofluid. Based on the experimental results, using micro-finned coiled tubes together with increasing the micro-fin helix angle and employing nanofluid enhance the heat transfer while increasing the pressure drop through the heat exchanger. In this study, inactive methods of enhancing heat transfer in the shell and tube heat exchangers, such as using smooth and micro-fins helically coiled tubes, and employing nanofluids as the working fluid, are investigated experimentally. A number of experiments are carried out for the flow of the Al2 O3 -water nanofluid in a shell and tube heat exchangers with helically coiled smooth as well as micro-finned tubes, and the pressure drop and the heat transfer coefficient are measured. The experiments are conducted for the Dean number ranging from 500 to 4000, for the fin helix angle between 18 and 25º, and for the nanofluid volume fractions of 0, 0.5 and 1%. The average heat transfer coefficients of the tube side of heat exchangers in each case is calculated using the Wilson plot method. Empirical correlations are proposed for the heat transfer coefficient of the nanofluid following through the tube-side of the heat exchanger in terms of the Dean number, the fin helix angle, the fin height and the volume fraction of the nanofluid. Based on the experimental results, using micro-finned coiled tubes together with increasing the micro-fin helix angle and employing nanofluid enhance the heat transfer while increasing the pressure drop through the heat exchanger. https://mej.aut.ac.ir/article_2927_2b64c2f19d868305aa8bbc2d72902cc5.pdf