High Power Ultrasonic Devices for Consumer Products

高功率超声波系统(HPUS)在不同的工业环境中运行，具有广泛的换能器和系统功能。高功率超声波最常见的用途是清洁，可用于小规模清洁的系统，例如清洁珠宝的系统，以及用于工业规模清洁的大型水箱。用于化学工业反应增强的超声波反应器的多样化应用是一个增长领域，超声波可以应用于雾化系统，以提供高效、可控的喷雾/雾化。此外，高功率超声的医疗应用也正在经历一个重要的发展和接受时期。这些技术甚至已经进入了整容手术的世界！因此，HPUS是一个不断增长的领域，但一个有趣的发展是在消费产品领域，超声设备正变得越来越普遍。该方案将围绕五个主题展开：1.HPUS的校准或特性。这是反应堆或在水负载下运行的单个传感器系统中的解决方案，但它们主要是侵入性的和/或频带受限的。对于消费市场产品，必须采取不同的方法，以非侵入性技术为重点：声发射和空气耦合超声波检测将作为潜在的解决方案进行调查。最近有报道称，除了传统的三相水--气体、液体和固体--之外，还有第四种相出现在界面上。这一阶段的深度可以通过应用光(UV、可见光和IR)来控制。我们感兴趣的是从空化的角度来看，清洗活动将在这个界面上进行，因此，研究这第四相水对高功率超声波系统清洗性能的潜在影响将是有兴趣的。这将是一个考虑界面光学刺激和评估空化性能的实验方案。在高功率超声系统中，关系到系统性能的关键部件是有源压电元件。为了改善整个系统的性能，换能器设计有三个主要方面需要解决，这些方面通常是相互关联的：压电材料；几何形状；以及加载/匹配材料。然而，最重要的是活性材料本身，近年来，压电材料的进步为工业应用的高功率系统提供了逐步改变性能的可能性。新的三元化合物(如PIN-PMN-PT[2])已被报道具有更高的机械Q和更高的能量密度，这为制造具有更高灵敏度的新一代超声换能器设计打开了新的可能性。重要的是，三元材料的居里温度为&gt；100oC，这足以满足许多商业应用。有限元建模和原型制造/测试的组合将评估新的设计和配置，并与标准的传统高功率超声波设备进行比较。4.消费产品的一个重要驱动因素将是设备的小型化。然而，这并不是一个直接的过程--较小的设备以较高的频率运行，这会导致较差的高功率性能(较高的空化阈值)。将进行一项全面的有限元模拟研究，考虑各种压电材料的选择、压电几何和组成材料。原型装置将在CUE实验室中进行制造、表征和测试。将研究阵列技术在高功率超声场控制中的应用。这种方法已经在生物医学领域(HIFU)实现，但对于典型的HPUS应用来说，需要较低的工作频率。

High power ultrasonic systems (HPUS) operate over a diverse industrial landscape and with a wide range of transducers and system capabilities. The most common use of high power ultrasound is for cleaning, with systems available at the small scale level, for example cleaning jewellery, up to large tanks for industrial scale cleaning. Diversification of applications into ultrasonic reactors for the chemical industry for reaction enhancement is a growth area and ultrasound can be applied in atomisation systems to provide an efficient, controllable spray/mist. Moreover, medical applications of high power ultrasound are also undergoing a significant period of development and acceptance. These techniques have even found their way into the cosmetic surgery world! So, the case has been made that HPUS is a growing sector, but an interesting development is in the consumer product domain where ultrasonic devices are becoming increasingly more common. The programme will be structured around five topics:1. Calibration or characterisation of HPUS. This are solutions for this in reactors or single transducer systems operating into a water load, but they are primarily invasive and/or band limited. For the consumer market products a different approach would have to be adopted, with non-invasive techniques the priority: acoustic emission and air-coupled ultrasonic detection will be investigated as potential solutions.2. It has recently been reported that in addition to the convention three phases of water - gas, liquid, and solid - there exists a fourth phase that occurs at interfaces. The depth of this phase can be controlled through the application of light (UV, visible and IR). Our interest is from a cavitation perspective, where cleaning activity would be at this interface and hence, an investigation on the potential impact that this 4th phase of water would have on the cleaning performance of a high power ultrasonic system would be of interest. This would be an experimental programme considering optical stimulation of an interface and assessing cavitation performance.3. The key component related to performance in a high power ultrasonic system is the active piezoelectric element. There are three main aspects to the transducer design that have to be addressed in order to improve the overall system performance and typically, these are inter-related: piezoelectric material; geometry; and loading/matching materials. However, the most significant is the active material itself and in recent years, advances in piezoelectric materials offer potential for a step change in performance in high power systems for industrial applications. New ternary compositions (e.g. PIN-PMN-PT [2]) have been reported with increased mechanical-Q and higher energy densities which opens new possibilities to produce a new generation of ultrasonic transducer designs with enhanced sensitivity. Importantly, the ternary materials have a curie temperature >100oC, which is sufficient for many commercial applications. A combination of finite element modelling and prototype manufacture/testing will evaluate new designs and configurations and compare to standard conventional high power ultrasonic devices. 4. A significant driver for consumer products would be device miniaturisation. However, this is not a straight-forward process - with smaller devices operating at higher frequencies, which have poorer high power performance (higher cavitation threshold). A comprehensive finite element modelling study will be undertaken considering various piezoelectric material options, piezoelectric geometries and constituent materials. Prototype devices will be fabricated, characterised and tested in the CUE laboratories.5. The application of array technology to provide control of the high power ultrasonic field will be investigated. This approach has been implemented in the biomedical domain (HIFU), but would require lower operating frequencies for typical HPUS applications.