A Review on Aero-Acoustics and Heat Transfer in Impinging Jets

Abstract

A summary of key discoveries regarding the industrial applications of impinging jets on a vertical plate. The summary explores the link between the dynamics and heat transmission on one hand and the relationship between heat exchange and acoustic coupling on the other hand. The objective of this research work is to investigate the vortex dynamics and heat transfer mechanisms in impinging jets. The jet impingement technique finds widespread use in the industry, it serves purposes such as drying, cooling, and heating. The impinging jet system involves directing a fluid jet with high-velocity onto a surface. The jet impingement results in high heat exchange rates and mass transfer rates, making it an attractive technique in various industrial processes. To investigate these mechanisms, a combination of experimental and computational methods was used, including flow visualization and numerical simulations. The study of vortex dynamics in impinging jets is crucial for understanding the heat transfer mechanisms involved. The flow characteristics of impinging jets, such as the Reynolds number (Re) of the jet, the distance from the blowing mouth to the impinged wall, and the geometry of the blowing mouth, significantly affect the vortex dynamics and heat transfer rates. Therefore, optimizing these parameters can result in significant improvements in heat transfer efficiency. Several methods were proposed to enhance heat transfer, these methods can affect the flow dynamic, the surface of impingement, the nozzle’s shape and size, and the impingement parameters such as the impact distance and the jet angle. For example, investigations have identified that optimal heat transfer took place at an inclination angle between 40 and 90 degrees. In addition, studies have reported enhancement in heat transfer with diamond orifices that reached up to 17%. The key findings of this paperwork include the identification of optimal impingement parameters that maximize heat transmission rates and the understanding of the significant relationship between the dynamics of the flow and the acoustic emissions. For instance, studies showed that synthetic jets can enhance convective heat transfer by 3 times compare to natural convection. The correlation between the flow dynamic and the heat transmission on one side, and the flow dynamics and acoustic emission on the other side, emphasizes the researcher to present acoustic-thermal coupled studies on the impinging jet; this topic needs more effort to understand the relation between the two phenomena. The conclusion highlights the significance of previous findings in industrial applications, suggesting control mechanisms capable of reducing noise and enhancing heat transmission.  

Keywords

• aero-acoustics
• flow control: heat transfer
• impinging jets
• vortex dynamics