Flow mechanism and heat transfer characteristic of sweeping jet impinging on confined concave surfaces

The sweeping jet actuator (SJA), a type of fluid oscillator, has attracted considerable attention in the areas of enhanced heat transfer and flow control. In this study, an unsteady Reynolds-averaged Navier-Stokes numerical investigation (k-omega baseline) was conducted to evaluate the flow mechanisms and heat transfer characteristics of a sweeping jet (SJ) on a confined concave surface. A conventional oscillating jet with a unit aspect ratio was used to generate the SJ. The heat transfer at the target surface and the flow details inside the flow field are discussed in detail to analyze the mechanism of the effect of SJ on impinging cooling. First, an appropriate numerical model was selected based on a comparison with a previous experiment. Subsequently, the time-averaged and time-resolved flow field and heat transfer results were investigated at three target distances for three different Reynolds numbers. The unsteady time-averaged results show that the SJ exhibits better heat transfer performance at higher Reynolds numbers and narrower target spacings than circle jet, which improves by 13% at Re = 30 000, H/D = 1. Subsequently, the turbulent kinetic energy and velocity loss theories were combined to compare the time-averaged and time-resolved flow field details of the two jets. The heat transfer characteristics of the target surface and the flow details inside the flow field in time and space were effectively correlated. Finally, the topology and three-dimensional (3D) vortex structure inside the confined channel were remodeled to better understand the unsteady sweeping process and provide theoretical support for subsequent applications.

Automated summary

In this study, the flow mechanisms and heat transfer characteristics of a sweeping jet on a confined concave surface were investigated using numerical simulations. The results showed that the sweeping jet exhibited better heat transfer performance compared to the circular jet at higher Reynolds numbers and narrower target spacings. The flow details inside the flow field were effectively correlated with the heat transfer characteristics of the target surface. Furthermore, the topology and three-dimensional vortex structure inside the confined channel were remodeled to provide theoretical support for subsequent applications.