Effect of Geometrical Parameters on Vortex Fluidic Oscillators operating with gases and liquids

Abstract

The fluidic oscillator is an interesting device developed for passive flow measurement. These microsystems can produce a high oscillating jet frequency with high flow velocity. The main advantages of fluidic oscillators is that no moving parts is included in the device [1, 2]. Commercial CFD code FLUENT was used to perform analysis of flows in microfluidic oscillator, Numerical simulations were carried out for different flow conditions, where water and air were used as working fluids. The oscillation frequencies were identified by the discrete fast Fourier transform method (FFT). Furthermore a low-pressure vortex of fluid flow in the oscillating chamber was observed between the jet stream and the attachment wall. The effect of the operating pressure and the oscillating chamber shape on the microfluidic oscillator performance is investigated. The velocity fluctuations of the feedback flows through the two feedback channels and the output were determined quantitatively. In addition, the behaviour of the low-pressure vortex in both models is analyzed. Moreover, numerical result reveled that a main vortex in the oscillation chamber and a small vortices at the end of nozzle are developed while oscillation, which maintains the deflection of jet flow to keep balancing between attachments wall. Comparison of our numerical simulations with available results showed reasonably and good agreement, which demonstrate the accuracy of our models.