International Journal of Heat and Mass Transfer, Vol.82, 51-65, 2015
Numerical analysis of flow resistance and heat transfer in a channel with delta winglets under laminar pulsating flow
In this paper, a comprehensive transient-state, three-dimensional model for heat transfer and fluid dynamics in a channel with LVG is presented. Compared with the existing research of pulsating flow for heat transfer enhancement, the overall and local dynamic response performance of velocity and vorticity, heat transfer and flow resistance, field synergy and entransy dissipation in the channel with LVG are detailed and analyzed in the present study. After model validation, the pulsating flow with four different cases is numerically investigated. The results indicate that both amplitude and period are very important parameter, which profoundly affect the flow and heat transfer performance. The overall j-factor is increased by 19.15%, 1.47%, 24.96% and 1.51% respectively for Cases 1-4. And the overall f-factor is increased by 17.61%, 1.06%, 17.58% and 1.06% correspondingly. All the results were pointed in the energy-saving performance evaluation plot, and analyzed by field synergy principle and entransy extreme principle. (C) 2014 Elsevier Ltd. All rights reserved.
Keywords:Longitudinal vortex generator;Pulsating flow;Heat transfer;Flow resistance;Mechanism study;Waste heat recovery