Effect of Components Height on a Jet Velocity for a Micro Synthetic Jet Actuator(Fluids Engineering)

Abstract

This paper describes a detailed study on effects of both cavity and orifice height on flow field governing a single synthetic jet in a quiescent air. The synthetic jet, known as a zero net mass-flux jet, is generated by a vibrating diaphragm to oscillate flow through a small orifice. The tested synthetic jet actuator consists of the orifice with the rectangular slot and cavity installed the PZT disk of 31.2mm diameter. The orifice height is chosen from 0.5, 1.0, 2.0 and 4.0mm, and the cavity height from 0.5 to 8.9mm, respectively. The test is conducted in variable input voltages and frequencies to PZT disk. With both the displacement of PZT disk on sinusoidal voltages and jet velocities above the orifice, the synthetic jet depends on not only oscillation of the PZT disk but sound pressure in the actuator. The simple lumped elements modeling is tested for the various cavity and orifice height, which does not require the iterative calculation on 1 degree forced oscillating. The analytical and experimental results are in good agreement on the maximum synthetic jet velocities for the orifice height of 0.5, 1.0 and 2.0mm in the cavity height higher than 0.75mm. The actuator with the cavity height of 2.5mm gives the maximum synthetic jet velocities to a high level, optimizing actuator size have to be considered the effect of both the cavity and orifice height for a micro synthetic jet actuator.