Ferroelectret sensor array for characterization of cavitation effects in ultrasonic cleaning

The demand for an increasing efficiency of ultrasonic cleaning in industrial manufacturing cannot be satisfied with the current empirical design approaches. This article describes the development of tools for the characterization of cavitation effects, which are the most important mechanisms of cleaning impact. The approach is based on the measurement of cavitation intensity by the assessment of characteristic acoustic spectral components. For this purpose, a sensor array using a novel, cellular structured ferroelectret is developed that can be easily applied to component surfaces. The electrical and acoustic characteristics of the sensor array are analyzed by measurements and finite element simulations. The correlation between acoustic spectral components and cavitation erosion on surfaces is deducted from cleaning experiments.