Dynamics Of And Radiated Acoustic Field Cavitation Bubbles In The Grinding Area Of Power Ultrasonic Honing

Power ultrasonic honing in the machining process can particularly generate bundantcavitaion bubbles, where happened in the grinding area composed of oilstone, cutting fluidand liner surface. The shock wave and microjets released by the collapsing cavitaion bubbleand cavitation bubble vibration in the grinding area is very vital for studying the machiningmechanism of power ultrasonic honing and deducing the cutting chatter generated. Taking acavitaion bubble in the grinding area into account, the dynamics and radiated acoustic field ofcavitaion bubble of power ultrasonic honing in the grinding zone are studied, by applicationthe basic theory of cavitation dynamics, mechanics of vibration, fluid mechanics andultrasonic honing. The methods of theoretical modeling, numerical simulation andexperimental verification are used. This paper provides a theoretical and experimental basisfor revealing the cavitation mechanism of the power ultrasonic honing in the grinding.The work of this paper and main results are as follows：1. Based on the present research of the power ultrasonic honing and ultrasonic cavitationfield, the sound field distribution of oilstone surface is obtained by the theoretical calculationand finite element analysis. The results show that the acoustic pressure value is greater thanthe cavitation threthold value in the grinding zone, which verifies the cavitation effect occurs.2. Combined the Rayleigh equation derived with the grinding mechanism of powerultrasonic honing, the dynamics model of single cavitation bubbles are established, especiallyconsidering the influence of ultrasonic honing speed and honing pressure on ultrasoniccavitation. Based on the superposition principle of velocity potential, the dynamics model ofbubble cavitation bubbles is established. And on this basis, the radiated sound pressure ofsingle and bubble cavitation bubble in the grinding area established, by solving the resonancefrequency equation, vibration equation, speed and acceleration equation of cavitaion bubble.3. The dynamics model of single and double cavitation bubble in the grinding zone arediscussed. The results show that the cavitation bubbles radius variation of power ultrasonichoning is lower that of ordinary ultrasonic cavitaion by less than an order of magnitude and the vibration cycle is obvious shorted. The radius variation of double cavitation bubbleexceeds that of single cavitation bubble by more than an order of magnitude and is lessaffected by the different ultrasonic frequency and phase.4. The radiated sound pressure of single cavitation bubble in the grinding area is simulatednumerically. The results show that the initial radius of the cavitation bubble in the grindingzone impact the acoustic pressure radiated by cavitation bubble mostly. The second influenceon radiated pressure is ultrasonic amplitude and honing pressure. The ultrasonic frequency isrelatively minimal impact on the cavitation bubble radiation sound pressure. The radiatedsound pressure of cavitation bubbles in the grinding area is studied. The results show the mostimpact on radiated pressure of two cavitaion bubbles is ultrasonic amplitude and the distanceto cavitation bubble. The second influence on radiated pressure is the honing pressure. Theminimum influence parameters are ultrasonic frequency and cavitation bubbles radius.5. Taking the reflection, refraction and mirroring principle of ultrasonic in the solidsurface into consideration, the radiated acoustic pressure near the oilstone wall is studied. Theresults show that the radiated pressure near the oilstone wall will be influenced by positionand incident angle to some extent.With the increasing of the distance to oilstone wall, theradiated sound pressure gradually increases. When the distance of cavitation bubble tooilstone wall is up to100μm, the radiated sound pressure of cavitation bubble but will reduce,as increasing the distance to the oilstone wall. The total radiated acoustic pressure ofcavitation bubble near the oilstone wall can be affected by the bigger cavitation bubble.6. The method of the test paper is provided to measure qualitatively the cavitation acousticfield in the grinding area.The experiments show that when the distance between PH paper andoilstone wall is about10mm and time is about120s, the optimal experimental results can beobtained. When the ultrasonic frequency is18.6kHz, the ultrasonic cavitaiton of centralsurface of oilstone wall is stronger than that of both sides of the oilstone wall. However, whenthe ultrasonic frequency is greater or less than18.6kHz, the ultrasonic cavitaiton of centralsurface of oilstone wall is weaker than that of other sides. The results are consistent with thequantitative measurement by using power sound intensity measuring instrument.