Flow dynamics and heat transfer analysis of a sweeping air jet - An experimental approach

Technological and environmental constraints are driving the development of enhanced heat transfer alternatives. In this context, the scope of this study encompasses sweeping jets generated by fluidic oscillators, which offer considerable potential for enhancing heat transfer. Initially, an experimental setup was developed to measure the flow velocity using a Laser Doppler Anemometer (LDA) and the heat transfer onto a target surface using a flux sensor. Moreover, videos capturing the free jet under various flow regimes were recorded using a Nikon (R) D850 camera. Concerning the flow dynamics of the sweeping jet, an upward trend in the estimated deflection angle of the jet and its oscillation frequency was noted at higher air flow rates. Heat transfer measurements on a surface indicated that an increase in air flow rate leads to improved heat transfer effectiveness of the jet. Finally, a comparison between the sweeping jet and the industry standard jet for surface cooling was carried out. This comparison revealed that the sweeping jet is highly sensitive to the flow regime at a distance from the plate of H / D = 6. In laminar flow, the sweeping jet outperforms the impinging jet in heat transfer performance. However, as the jet transitions to turbulent flow, the impinging jet exhibits superior thermal characteristics for enhancing heat transfer.