Energy, Vol.116, 341-352, 2016
Heat transfer enhancement in an air to water heat exchanger with discontinuous helical turbulators; experimental and numerical studies
Influence of perforated and typical helical fin on hydrothermal treatment in a water to air heat exchanger is presented. Air and water move through outer and inner pipes, respectively. Effects of pitch ratio (A), Reynolds number (Re-a) and open area ratio (PR) are examined. Empirical formulae for thermal performance (eta), Darcy factor (f) and Nusselt number (Nu) are obtained. NSGA II and ANSYS FLUENT14 are chosen for optimization and numerical simulation. Results indicate that higher open area ratio offers greater thermal performance than the lower one. Temperature gradient attenuates with enhance of open area ratio. (C) 2016 Elsevier Ltd. All rights reserved.