Modal analysis and nonlinear characterization of an airborne power ultrasonic transducer with rectangular plate radiator

Abstract

Some industrial processes like particle agglomeration or food dehydration among others can be enhanced by the use of power ultrasonic technologies. These technologies are based on an airborne power ultrasonic transducer (APUT) constituted by a pre-stressed Langevin-type transducer, a mechanical amplifier and an extensive plate radiator. In order to produce the desired effects in industrial processing, the transducer has to vibrate in an extensional mode driving an extensive radiator in the desired flexural mode with high amplitude displacements. Due to the generation of these high amplitude displacements in the radiator surfaces, non-linear effects like frequency shifts, hysteresis or modal interactions, among others, may be produced in the transducer behavior. When any nonlinear effect appears, when applying power, the stability and efficiency of this ultrasonic technology decreases, and the transducer may be damaged depending on the excitation power level and the nature of the nonlinearity. In this paper, an APUT with flat rectangular radiator is presented, as the active part of an innovative system with stepped reflectors. The nonlinear behavior of the APUT has been characterized numerically and experimentally in case of the modal analysis and experimentally in the case of dynamic analysis. According to the results obtained after the experiments, no modal interactions are expected, nor do other nonlinear effects.

Review of the design of power ultrasonic generator for piezoelectric transducer

“…When high-power and high-intensity ultrasonic waves act on the fluid medium (including gas, liquid, and multiphase medium), the ultrasonic cavitation effect, thermal effect, and mechanical effect will be involved in the processing of workpieces. Among them, the ultrasonic cavitation effect can cause a series of secondary effects by collapsing cavitation bubbles, which generally results in the phenomena of micro-eddy current, micro jet, shockwaves, local high temperature and high pressure [10] , [26] , [27] , [28] . So based on these effects, the PUT has been widely utilized in many industrial fields, such as in the ultrasonic cleaning and atomization field which is mainly applied to the cleaning and sterilization of medical equipment [8] , [29] , anti-scaling and descaling [30] , [31] , [32] , wastewater treatment [33] , microbial inactivation [8] , agricultural aerosol cultivation [34] , atomization drug delivery [35] , paint spraying [6] , [36] , spherical metal powder manufacturing [37] , liquid drop levitation [38] , and the cleaning of large-scale integrated circuits, optical devices, silicon chips, and other sub-micron particle products [39] .…”

“…But PT has obvious nonlinear effects, such as frequency drift, hysteresis, and modal interaction, while its modal interaction may appear as one or more modal responses at frequencies other than the operating frequency. These nonlinear effects mostly cause losses within the piezoelectric material, namely, dielectric loss, elastic loss, and piezoelectric loss [26] , [147] . To explore the mechanism of the above nonlinear effects， there are three PT’s equivalent circuits including the Mason model, KLM model, and BVD model, which can be selected depending on the practical situation [148] , [149] , [150] , [151] , [152] .…”

Sonoprocessing: From Concepts to Large-Scale Reactors

“…The plate radiator can be designed in different shapes such as circular, rectangular or cylindrical, and it can incorporate a stepped, grooved or stepped-grooved profile (Figure ). − The interested reader can find more information on the design of plate radiator geometry and profile on the review by Gallego-Juárez et al…”

Development and research of a new method of gas cleaning from particles less than 2.5 micron in size

“…Эффективность коагуляции излучателя поршневого типа с увеличением концентрации частиц возрастает линейно и достигает своего максимального значения 83% при значении концентрации 24•10 -3 г/м 3 , в то время как эффективность дискового излучателя достигла своего максимума 96% при концентрации уже 18•10 -3 г/м 3 . То есть, создание вихревых течений эффективно для сред с малой концентрацией частиц [3,[6][7][8].…”