Research And Optimization Of Ultrasonic Cavitation Field Based On Bath-type Sonoreactor

Power ultrasound has been widely used in various fields of modern industry such as cleaning,sewage treatment,and nano-materials fabrication.Especially in the field of chemistry,power ultrasound has developed rapidly in recent years.This is mainly due to the nonlinear phenomenon termed ultrasonic cavitation.When ultrasound is applied to water,some of the bubbles will collapse,causing intensive micro-pressure-shock and micro-jet,as well as some localized micro-regions with high pressure and temperature within microseconds.Ultrasound cavitation mainly occurs via sonoreactor of which related parameters will have a vital impact on cavitation activity.Based on the bath-type sonoreactor,we firstly optimized the characterization method of ultrasonic cavitation field.Both aluminum foil erosion experiment and hydrophone measurement were optimized in the experiment.Meanwhile,Fluid-structure interaction(FSI)harmonic response strategy was proposed in the simulation.The good agreement of simulation results with experimental ones indicated that the simulation was effective to predict the cavitation activity and design complex cavitation field within sonoreactors.The influence of sound direction on the acoustic field with up to five directions was systematically studied.Results of simulation coincided well with that of experiment.Based on the results,several influence rules of sound directions were proposed.Optimal acoustic field with high intensity and good uniformity was obtained.The dependence of cavitation intensity and distribution on liquid height were both systematically investigated.Five liquid heights were analyzed.The results demonstrated that the standing wave field significantly enhanced cavitation intensity while worsened cavitation uniformity.Several influence rules for improving liquid height were proposed.We further explored a continuous liquid-height-changing method which was able to remarkably improve cavitation field uniformity and keep the cavitation intensity relatively high at the same time.Furthermore,the effects of bubble content and size were explored by COMSOL software.The calculation results indicated that the bubbles could cause acoustic attenuation,while improve the acoustic field uniformity to some extent.Consequently,several optimal thoughts by using bubbles were proposed.Overall,the influences of the direction of sound direction,liquid height and bubbles were systematically studied via both optimized simulation and experiment.This work provides useful guidelines for acoustic field design and optimization of sonoreactor.