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- 2016
超声频率和液位对空化场的影响
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Abstract:
空化效应是超声在化学反应过程中发挥作用的主要原因, 采用谱分析法衡量空化场强弱, 引入标准差评价空化场的均匀程度, 在标称频率20 kHz和40 kHz的清洗槽内, 研究了超声频率和槽内液位对空化场的影响效果．结果表明：超声波换能器使用中存在频率漂移现象, 利用水听器、示波器结合MATLAB软件测量计算实际工作频率分别为23.93 kHz和42.72 kHz; 低频时空化场的平均强度高, 但高频时空化场的均匀性更好; 清洗槽内存在谐振液位(30 mm、45 mm、60 mm、75 mm), 在这些液位处空化强度和均匀性均较好．
Cavitation plays an essential role in sonochemical reaction process. The spectrum analysis method was adopted to measure the cavitation intensity and the standard deviation was introduced to evaluate the uniformity of the cavitation field. The effects of ultrasonic frequency and liquid level on the cavitation field were studied in this paper in the ultrasonic cleaning tank with nominal frequencies of 20 kHz and 40 kHz. The results show that the frequency drift occurs when the ultrasonic transducers work. To analyze the frequency drift phenomenon，this paper puts forward a method to measure the actual frequency at work using the hydrophone，oscilloscope and MATLAB. The actual frequencies were measured to be 23.93 kHz and 42.72 kHz. Results indicate that the average intensity of cavitation is higher at low frequency，but the uniformity of cavitation distribution is better at high frequency. There are some resonance liquid levels at which the cavitation intensity and uniformity are both satisfactory such as at 30 mm，45 mm，60 mm and 75 mm
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