【作者】 王巧霞；

【导师】 牛勇；

【作者基本信息】 陕西师范大学 ， 声学， 2007， 硕士

【摘要】 随着科学技术的发展，超声技术在众多领域得到广泛的应用，除功率超声、水声、超声检测、医学超声等经典超声学科外，超声清洗、超声化学、超声生物学等声学边缘学科也迅速发展，在这些领域内不断有新的成果出现。在这些应用中，超声空化是引发各种物理、化学和生物效应的主要机理，从而空化现象的理论和实验研究也成为人们关注的焦点。空化现象的产生受多种因素的影响，而且产生空化效应后的声传播出现复杂的非线性现象，这为空化效应理论研究带来许多不确定因素，从而使空化效应的理论研究进展缓慢，对空化效应的研究主要存在于实验和应用的研究。在超声空化场中，液体中的空化气泡，随着声场变化而膨胀和收缩，将声能高度集中，会产生发光现象，称为声致发光。声致发光中气泡的运动将低能量密度的声能转化成高能量密度的光能。为了研究这个巨大的能量聚集的复杂原理，研究者对声致发光的气泡动力学及发光机理不断进行探索，使声致发光现象成为非线性声学和物理学研究的一个热点。声致发光现象按照气泡的数目分为多泡声致发光和单泡声致发光两种类型。在1934年，由德国科隆大学的H．Frenzel和H．Schultes研究声纳时偶然观察到，空化时除了气泡爆裂声，往往还伴随着肉眼可见的发光，一般把它称为“多气泡声致发光现象”；在1990年，密西西比大学的D．F．Gaitan做博士论文时将单气泡成功陷在盛有水的烧瓶中心并使其稳定持续地发光数小时，也就是“单气泡声致发光现象”。本文从理论和实验两个方面对声致发光进行研究，主要包括以下四部分内容及结果：(1)根据鲁米诺增强声致发光原理，用摄像机拍摄到空化气泡的运动全过程。(2)自制了微光测量仪，分析仪器各部分电路的组成和功能。(3)用微光测量仪对超声清洗槽内的声致发光强度进行测量。分别作用22kHz、27kHz和40kHz的超声波，改变电功率密度值对应得到声致发光强度的变化情况，结果表明：输入电功率密度只有超过声致发光阈值时，液体中才会出现声致发光现象。在22kHz换能器辐射下，发光强度随电功率密度的增大类似直线型增大，但没有达到饱和值；在27kHz换能器辐射下，发光强度随电功率密度的增大类似阶梯型增大，最后达到饱和值；在40kHz换能器辐射下，发光强度随电功率密度的增大出现起伏，过程中出现两次饱和值。(4)在实验和理论上分析超声作用频率对声致发光强度的影响。超声的频率不同，其声致发光的阈值也不同，频率越高，声致发光的阈值也随之升高。由于声信号在一个振动周期内就能产生一次发光，所以单位时间内，不同频率的超声产生的发光次数也不同。因此，即使是在同一电功率密度条件下，不同的超声频率发光强度也不同，所以不同频率条件下的超声具有不同的发光光强-电功率密度关系的曲线关系。更多还原

【Abstract】 Ultrasound has been extensively applied in many fields with the development of science and technology. For example classic power ultrasound, wine ultrasound, ultrasound measurement, ultrasound medicine, the marginal subjects such as ultrasound cleaning, sonochemistry and sonobiology have advanced rapidly, and new results have came out now and then. Ultrasonic cavitation is the main mechanism that induces all kinds of physical, chemical and biologic effects during these applications. So the researches of theory and experiment of cavitation become focus. The cavitation correlates with many factors, and going with complicated nonlinearity, which makes many difficulties in the researches of the theory of cavitation, so the researches of cavitation are mostly experiment and applications.In the circumstance of the ultrasound cavitation field, the cavitation bubbles of the fluid inflate and contract with the acoustic field. Highly intensive energy will be concentrated in the bubbles and that will flash. This phenomenon is called sonoluminescence. In the sonoluminescence the movement of the bubbles converts acoustic energy of low-energy intensity to luminous energy of high-energy intensity. To study the theory the energy concentrative, researchers carry through disquisition continually to the bubble dynamics and mechanism of sonoluminescence, that makes sonoluminescence become hot research in physics and nonlinear acoustics. Sonoluminescence is assorted two types of single-bubble sonoluminescence and multiple-bubble sonoluminescence according to amount of air bubble. In 1934, H. Frenzel and H. Schultes in Cologne university who found accidentally macroscopic illumination besides the crepitation of bubbles when they researched sonar, which are generally called "Multiple-bubble sonoluminescence". In 1990, D. F. Gaitan in Mississippi university made single bubble be entangled in the center of water and let it illuminate a few hours stably and persistently, which are generally called "Single-bubble sonoluminescence".In this paper following work has been done based on the theory and experiment research of sonoluminescence, the four main contents and resents of the research are as follows:1. The principle that Luminol enhances sonoluminescence, filming the procession of the cavitation bubble’s athletics with camera.2. The glimmer measurement instrument is designed and made, and the characteristics and function of it are analyzed.3. Measuring sonoluminescence intensity of cleaning tank with the glimmer measurement instrument. With 22 kHz’s, 27 kHz’s and 40 kHz’s Ultrasound, changing power density and getting to mutual sonoluminescence intension, the result indicated: only power density exceeds threshold value average acoustic intension in fluid, sonoluminescence will happen. With 22 kHz’s transducer radiation, luminous intensity accesses straightly with power density, but not to saturation value; with 27 kHz’s transducer radiation, luminous intensity accesses trap with power density; with 40 kHz’s transducer radiation, luminous intensity accesses wave with power density, and get to saturation value twice.4. Analyzing ultrasound frequency to affect sonoluminescence intensity. Different frequency correspond different luminous threshold value. Higher frequency correspond higher threshold value. As to sound signal engender luminescence first in a sound cycle, different frequency ultrasound engender different times of luminescence in unit time. In the same power density, different frequency correspond different luminous intensity, so in the different frequency, different curve between luminous intensity and power density.更多还原