Nonstationary Vibrations of Piezoelectric Atomizer: Experimental Analysis and Mathematical Model

Abstract

The nonstationary vibrations of an atomizer with time-varying drop mass were investigated in this study. The atomizer made use of brass and piezoceramic discs driven by a sine input voltage. When the acceleration applied by the piezoelectric disc reached a critical value, small droplets were ejected from the surface of the mass and the liquid drop mass decreased with respect to time. This study consisted of two parts. In the experimental one, a laser vibrometer was used to measure displacements and accelerations of the disc, while in the theoretical part, a mathematical model was developed for different applied acceleration values. It was observed that the atomization rates of the drop were exponentially proportional to applied accelerations. In the theoretical part, the mathematical model was developed for the behaviour of the atomizer with time-varying drop mass. The nonlinear equation of motion was solved analytically by means of the multiple scales method. The nonstationary response of the system obtained numerically and experimentally was compared. It was found that the experimental results are in good agreement with the theoretical solution. The aim of this work was to determine the effects of initial accelerations on the atomization rates, as well as mass variation and initial drop mass on the transient behaviour of the system. The authors concluded that the duration of the transient behaviour and the displacement amplitude of the system increased as the initial drop mass and atomization rate increased with acceleration.