Nanofluid heat transfer and entropy generation through a heat exchanger considering a new turbulator and CuO nanoparticles M. Sheikholeslami 1,2 • M. Jafaryar 2,3 • Ahmad Shafee 4,5 • Zhixiong Li 6,7 Received: 8 August 2018 / Accepted: 20 October 2018 Ó Akade´miai Kiado´, Budapest, Hungary 2018 Abstract In this research, a numerical macroscopic approach has been employed to analyze nanofluid entropy generation and turbulent flow through a circular heat exchanger with an innovative swirl flow device. A homogenous model was con- sidered for nanofluid. Minimizing entropy generation can be considered as a very important goal for designing a heat exchanger, so we focus on this factor in the present attempt. Simulations were presented to show the influences of the geometric parameter (revolution angle) and inlet velocity on hydrothermal and second-law treatment. Related correlations for thermal and frictional entropy parameters as well as Bejan number have been presented. Outputs reveal that augmenting revolution angle increases the frictional entropy generation. Increasing secondary flows leads to a reduction in thermal entropy generation due to a decrement in thermal boundary layer thickness. By improving convective flow, Bejan number reduces. Keywords Nanofluid  Heat transfer  Passive technique  Heat exchanger  Entropy generation List of symbols S gen;f Viscous entropy generation Nu Nusselt number T Fluid temperature Re Reynolds number P Pressure L Length of pipe f Darcy friction factor Pr Prandtl number S gen;th Thermal entropy generation D Pipe diameter Greek symbols a Thermal diffusivity / Concentration of nanofluid l Dynamic viscosity of nanofluid q Density b Revolution angle Subscripts s Particles nf Working fluid f Fluid Introduction To reach the best design of a heat exchanger, both hydrothermal and second-law behaviors need to be consid- ered. To enhance its efficiency, nanofluid can be considered as a working fluid in a heat exchanger. Nanofluids have many applications, such as in solar energy [1], solidification/melting & Zhixiong Li zhixiongli.cumt@gmail.com 1 Department of Mechanical Engineering, Babol Noshirvani University of Technology, Babol, Islamic Republic of Iran 2 Renewable Energy Systems and Nanofluid Applications in Heat Transfer Laboratory, Babol Noshirvani University of Technology, Babol, Iran 3 MR CFD LLC, No 49, Gakhokidze Street, Isani-Samgori District, Tbilisi, Georgia 4 FAST, University Tun Hussein Onn Malaysia, 86400 Parit Raja, Batu Pahat, Johor State, Malaysia 5 Applied Science Department, College of Technological Studies, Public Authority of Applied Education and Training, Shuwaikh, Kuwait 6 School of Engineering, Ocean University of China, Qingdao 266110, China 7 School of Mechanical, Materials, Mechatronic and Biomedical Engineering, University of Wollongong, Wollongong, NSW 2522, Australia 123 Journal of Thermal Analysis and Calorimetry https://doi.org/10.1007/s10973-018-7866-7