Acoustic Cavitation Theory and Equipment Design Principles for Industrial Applications of High-Intensity Ultrasound

A multitude of useful physical and chemical processes promoted by ultrasonic cavitation have been described in laboratory studies. Industrial-scale implementation of the high-intensity ultrasound has, however, been hindered by several technological limitations, making it difficult to directly scale up the ultrasonic systems in order to transfer the results of the laboratory studies to the plant floor. High-capacity flow-through ultrasonic reactor systems required for commercial-scale processing of liquids can only be properly designed if the energy parameters of the cavitation region are correctly evaluated. Conditions which must be fulfilled to ensure an effective and continuous operation of an ultrasonic reactor system are provided in this book. Copyright 6 CONTENTS 7 PREFACE 9 INTRODUCTION 11 SHOCK-WAVE MODEL OF ACOUSTIC CAVITATION 13 2.1. VISUAL OBSERVATIONS OF ACOUSTIC CAVITATION 14 2.2. JUSTIFICATION FOR THE SHOCK-WAVE APPROACH 15 2.3. THEORY 16 2.3.1. Oscillations of a Single Gas Bubble 17 2.3.2. Cavitation Region 22 2.4. SET-UP OF EQUATIONS FOR EXPERIMENTAL VERIFICATION 27 2.4.1. Low Oscillatory Velocities of Acoustic Radiator 27 2.4.2. High Oscillatory Velocities of Acoustic Radiator 29 2.4.3. Interpretation of Experimental Results of Work [26] 30 2.5. EXPERIMENTAL SETUP 31 2.6. EXPERIMENTAL RESULTS 31 2.7. SECTION CONCLUSIONS 35 SELECTION AND DESIGN OF MAIN COMPONENTS OF HIGH-CAPACITY ULTRASONIC SYSTEMS 37 3.1. ELECTROMECHANICAL TRANSDUCER SELECTION CONSIDERATIONS 37 3.2. HIGH POWER ACOUSTIC HORN DESIGN PRINCIPLES 38 3.2.1. Criteria for Matching a Magnetostrictive Transducer to Water at Cavitation 40 3.2.2. Five-Elements Matching Horns 43 3.2.2.1. Design Principles 43 3.2.2.2. Analysis of Five-Element Horns 47 3.2.3. Experimental Results 52 3.3. SECTION CONCLUSIONS 55 ULTRASONIC REACTOR CHAMBER GEOMETRY 59 FINAL REMARKS 61 REFERENCES 63 INDEX 67