Synthetic jet cross-flow interaction with orifice obstruction

Purpose - The purpose of this paper is to describe the flow structure and the time-resolved and time-mean heat transfer characteristics in the interaction between a synthetic jet and a cross flow, when an obstruction reduces the cross-section of the orifice where the jet is formed. Design/methodology/approach - The microchannel flow interacted by the pulsed jet is modeled using a two-dimensional finite volume simulation with unsteady Reynolds-averaged Navier-Stokes equations while using the Shear-Stress-Transport (SST) k-omega turbulence model to account for fluid turbulence. Findings - The computational results show a good and rapid increase of the synthetic jet influence on heat transfer enhancement when the obstruction of the orifice is superior to 30 per cent and the synthetic jet oscillating amplitudes are below 50 mu m. It is found that when the obstruction is close to the exit orifice, the heat transfer enhancement is significant. The obstruction has proved to accelerate the jet and change the formation of large vortical structures. Additional windward vortices appear, which influence the flow field and enhance the heat transfer. Research limitations/implications - The work proposes the use of a compound enhancement technique for electronics cooling. A limited range of operating conditions and geometrical configurations is presented. A further analysis of the performance evaluation, based on the increased energy consumption of the device, would complement the study. Originality/value - The authors provide a compound technique to enhance heat transfer in synthetic-jet electronic cooling devices.