1 Copyright © 2013 by ASME Proceedings of the ASME 2013 Fluids Engineering Division Summer Meeting FEDSM2013 July 7-11, 2013, Incline Village, Nevada, USA FEDSM-16115 OPTIMIZED CHAOTIC HEAT EXCHANGER CONFIGURATIONS FOR PROCESS INDUSTRY: A NUMERICAL STUDY ABSTRACT A numerical investigation of chaotic laminar flow and heat transfer in isothermal-wall square-channel configurations is presented. The computations, based on a finite-volume method with the SIMPLEC algorithm, are conducted in terms of Péclet numbers ranging from 7 to 7×10 5 . The geometries, based on the split-and-recombine (SAR) principle, are first proposed for micromixing purposes, and are then optimized and scaled up to three-dimensional minichannels with 3-mm sides that are capable of handling industrial fluid manipulation processes. The aim is to assess the feasibility of this mass- and heat- transfer technique for out-of-laboratory commercial applications and to compare different configurations from a process intensification point of view. The effects of the geometry on heat transfer and flow characteristics are examined. Results show that the flux recombination phenomenon mimicking the baker’s transform in the SAR-1 and SAR-2 configurations produces chaotic structures and promotes mass transfer. This phenomenon also accounts for higher convective heat transfer exemplified by increased values of the Nusselt number compared to the chaotic continuous-flow configuration and the baseline plain square-duct geometry. Energy expenditures are explored and the overall heat transfer enhancement factor for equal pumping power is calculated. The SAR-2 configuration reveals superior heat-transfer characteristics, enhancing the global gain by up to 17-fold over the plain duct heat exchanger. KEYWORDS Process intensification; mass and heat transfer enhancement; chaotic advection; square channel; Split-And- Recombine heat exchanger/reactor NOMENCLATURE D h channel hydraulic diameter (m) f friction factor h convective heat-transfer coefficient (W m -2 K -1 ) L channel developed length (m) n number of splitting and recombination (SAR) steps Nu Nusselt number P Pressure (Pa) Pe Péclet number Pr Prandtl number Re Reynolds number T temperature (K) u local velocity (m s -1 ) volume-averaged velocity (m s -1 ) U inlet velocity (m s -1 ) Greek symbols α fluid thermal diffusivity (m 2 s -1 ) η thermal enhancement factor κ fluid thermal conductivity (W m -1 K -1 ) ρ fluid density (kg m -3 ) φ heat flux density (W m -2 ) μ fluid dynamic viscosity (Pa s) ∆P pressure drop (Pa) Subscripts 0 plain channel b bulk value x local value w wall u Akram Ghanem LUNAM Université, Laboratoire de Thermocinétique de Nantes, CNRS UMR 6607, 44306 Nantes, France Thierry Lemenand LUNAM Université, Laboratoire de Thermocinétique de Nantes, CNRS UMR 6607, 44306 Nantes, France Dominique Della Valle ONIRIS – Nantes 44322 Nantes, France Hassan Peerhossaini Univ. Paris Diderot, Sorbonne Paris Cité, Institut des Energies de Demain (IED), 75013 Paris, France