Numerical evaluation of turbulence heat transfer and fluid flow of hybrid nanofluids in a pipe with innovative vortex ge
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Numerical evaluation of turbulence heat transfer and fluid flow of hybrid nanofluids in a pipe with innovative vortex generator Seyed Soheil Mousavi Ajarostaghi1,2 · Mohammad Zaboli3 · Mehdi Nourbakhsh4 Received: 16 February 2020 / Accepted: 23 August 2020 © Akadémiai Kiadó, Budapest, Hungary 2020
Abstract In the present work, hybrid nanofluids flow and heat transfer in a pipe equipped with vortex generator are evaluated numerically. At the first part, the impact of the type of working fluid (two various hybrid nanofluids in comparison with pure water at φ = 3%) and at the second part, impact of the volume concentration of selected hybrid nanofluid (based on section one) on the turbulence thermal performance of the pipe with innovative vortex generator are evaluated numerically. All the simulations were performed for the Reynolds number range between 4125 and 5363. The considered hybrid nanofluids include silver (Ag) and graphene (HEG) nanoparticles/water and MWCNT–Fe3O4/water. The proposed vortex generator has 18 blades to create secondary flows. Also, five output ports are considered at the conical part of vortex generator (four side outputs and one axial one). Results indicated that using both two techniques of heat transfer enhancement in a pipe including proposed vortex generator and hybrid nanofluids leads to higher heat transfer rate. As a result, the MWCNT–Fe3O4/water hybrid nanofluid has better thermal performance in all studied Reynolds number. At low Reynolds number (Re = 4125), the maximum thermal performance was achieved at φ = 1% by 11.3% growth in thermal performance. Also, case with φ = 5% has a minimum improvement, 10.5%. Furthermore, at high Reynolds number (Re = 5363), the highest and lowest growths belong to cases φ = 3% and φ = 7% by 9.9 and 7% improvement in thermal performance, respectively. Keywords Heat transfer enhancement · Thermal performance · Hybrid nanofluid · Vortex generator · Turbulent Abbreviations A Area (m2) Cp Specific heat capacity (kJ/kg K) D1 Outlet diameter of vortex generator (m) D2 Inlet diameter of vortex generator (m) D3 Blades diameter of vortex generator (m) * Seyed Soheil Mousavi Ajarostaghi [email protected] Mohammad Zaboli [email protected] Mehdi Nourbakhsh [email protected] 1
Department of Mechanical Engineering, Babol Noshirvani University of Technology, Babol, Iran
2
Department of Mechanical Engineering, Université de Sherbrooke, 2500 Boulevard de l’Université, Sherbrooke, QC J1K 2R1, Canada
3
Department of Mechanical Engineering, University of Semnan, Semnan, Iran
4
Department of Mechanical Engineering, Mazandaran University of Science and Technology, Babol, Iran
D4 Diameter of pipe (m) D5 Diameter of side outputs of vortex generator (m) Dc Helix diameter (m) dh Hydraulic diameter (m) f Darcy friction factor H Helix height (m) h Heat transfer coefficient (W/m2 K) k Thermal conductivity (W/m K) L1 Length of the vortex generator with blades (m) L2 Length of the conical part of vortex generator (m) l Pl
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