【作者】 彭昀；

【导师】 汪炜；

【作者基本信息】 南京航空航天大学 ， 机械制造及其自动化， 2009， 硕士

【摘要】 区别于传统超声波分散,本文提出了浴槽式脉冲兆赫超声分散技术,即采用大功率高频兆赫超声换能器,在液体介质中产生高速、强辐射声流能来进行材料分散,同时有效抑制传统超声处理中无法避免的因过度空化而造成的材料损伤。该技术将超声技术、先进制造技术和材料科学结合起来,为材料分散提供新的技术手段。它具有能量可控性好、成本低、安全环保和应用范围广等优点,将在材料分散和制备领域拥有广阔的应用前景。本文主要研究内容如下:1.从声空化、空化气泡运动学、声流等方面对兆赫超声分散的作用机理进行了探讨。从理论上证明了当超声频率提高至600kHz以上时,声场内的空化阈值提高、可闭合空化气泡数减小,从而有效抑制了空化损伤。同时,初步探讨了兆赫超声分散系统的能量转化过程,分析了兆赫声场中的高速、强辐射声流能以及高频振荡作为材料分散主要动力的理论条件和作用机理。2.设计制作了单阵元换能器,总结了设计、制作换能器的工艺流程。设计制作了兆赫逆变电源,利用电力分析仪监测了兆赫逆变电源的输入、输出波形。3.应用兆赫超声分散技术进行了纳米材料分散试验。利用该方法对PZT纳米颗粒进行了分散试验。利用扫描电镜、透射电镜、X射线衍射仪等仪器对分散效果进行了检测和表征,结果表明该技术分散效率高、效果好。4.试验了兆赫超声分散技术用于油包水/水包油乳液制备的效果,制备了反向胶束微反应器和无乳化剂乳浊液。利用工具测量显微镜对所制备乳液的分散性进行了分析,结果显示经兆赫超声精细化分散后的乳液分散性最佳。更多还原

【Abstract】 Distinguishing from dispersion in traditional ultrasonic wave, this thesis proposes, for the first time, a pulsed megasonic dispersion technology in a bath trough type. Namely by using high frequency megasonic transducer with high efficiency, high speed sonic flow and strong sound pressure, which responsible for the material dispersion, are produced in liquid medium. Simultaneously, it is effective to suppress material damage which the tradition ultrasonic dispersion is unable to avoid because of the excessive cavitation inherited. This technology unifies supersonic technology, the advanced technique of manufacture and materials science, providing a new technical method for material dispersion. In the mean time, it features good energy controllability, cost efficiency and environmental friendliness. The megasonic dispersion technology has broad prospect of applications in the fields of material dispersion and preparation. Main contents in this thesis are as follows:1. Discussion about the megasonic dispersion mechanism on the basis of sound cavitation, cavitational air bubble kinematics and sonic flow. Theoretically prove that when the ultrasonic frequency exceeds 600 kHz, the cavitation threshold values up, while the number of cavitational air bubble reduces, thus the cavitation damage to the materials would be suppressed effectively. At the same time, this thesis initially discusses the process of energy conversion in this megasonic dispersion system, and analyzes the theoretical conditions required for the high speed sonic flow effect and the higher mode of sonic oscillation to be the main power in the megasonic sound field and the material dispersion process.2. Summary of design of the single element transducer and the process of manufacture. A mega Hertz inverter is designed and manufactured as power source. Debugging details of the input and output waveform of mega Hertz inverter recorded by an electric power analyzer.3. The application of megasonic dispersion method to nano particles dispersion, specifically PZT nano particles. The effects are characterized by Scanning Electron Microscopy, X-Ray Diffraction and Transmission Electron Microscopy. The results indicate a high efficiency and harmless effects.4. Preparations of O/W, W/O emulsion and ultra-large reverse micellar micro reactor are reported, as well as the initial study of non-emulsifier emulsion by the megasonic dispersion technology. The emulsion dispersivity is characterized by Measuring Microscope, which demonstrates that a combined refinement treatment by magasonic dispersion has the best dispersive effects.更多还原