摘要
隨著科技發展，各國開始注意空氣汙染造成的危害；尤以懸浮微粒（PM10、PM2.5）會對人呼吸道與心血管疾病造成危害，因此懸浮微粒的清除與過濾近幾年成為各國積極開發目標。由於懸浮微粒的來源大部分來自於工業工廠的廢氣排放，導致工廠廢氣清淨與過濾設備的需求日趨增加。目前工業界最常見懸浮微粒的處理方式為採用袋濾集塵器（baghouse dust collector），透過纖維薄膜的袋狀過濾器，可有效抑制微小粒徑粉塵之排放。然而過濾的懸浮微粒將會堵塞濾布的過濾孔隙，同時微粒間的表面作用力將導致粉塵黏著於濾網上，阻礙廢氣的過濾與排出，導致過濾效率隨時間減少。有鑑於此，本論文提出透過建立超音波聲音懸浮之非接觸微重力技術，利用所設計的壓電振動子產生超聲波，互相耦合產生出一套高強度且穩定的駐波式超聲場懸浮架構。使廢氣內的懸浮微粒可聚集在駐波的節點上，實現抑制懸浮微粒的空氣清淨效果。本論文所提出的超聲場粉塵移除技術可實現非接觸分離粉塵與氣體，不須濾網需求即可達到微粒抑制成效，可避免因懸浮微粒黏著濾網導致過濾效率低落。
關鍵詞：壓電振動子、超聲波懸浮技術、非接觸空氣清淨、超音波聲壓耦合Abstract
With the development of industrial technologies, air pollutions are always a very critical issue, especially the harmfulness of suspended particles, such as PM10, PM2.5, etc., which could endanger human health and result in respiratory and cardiovascular diseases. Therefore, developing the methods of suspended particles removal and purifier has become a significant topic of research. According to the analysis of suspended particulate sources, in Taiwan, the greatest resource is the exhaust emissions generated from the industrial production processes and factories (23%). As for the equipment of exhaust emission purification, a dust collector baghouse is the most popular method to remove suspended particles for its advantages of simple structure, low cost, and high filtering efficiency. However, the filtered suspended particles will block the filter pores of the filter cloth, and the surface force between the particles will cause the dust to stick to the filter screen, which hinders the filtration and discharge of exhaust gas, and causes the filtration efficiency to decrease over time. In order to filter out ultra-fine particles, a non-contact microgravity technology by acoustic levitation was proposed in this paper. A piezoelectric transducer was utilized to generate ultrasonic waves. According to the plane-wave transmission theory, the location of a reflection plate can be estimated to build a stable and strong strength field of standing-wave acoustic levitation structure. With the use of the standing-wave acoustic levitation structure, the suspended particles in the exhaust gas can be fixed at the nodes of the standing wave, and the ultra-fine dust can be separated from the exhaust emissions to reach the effect of air purification. Therefore, in this paper, a contactless purification technology with ultrasonic sound pressure can realize non-contact separation of dust and gas and achieve particle suppression effect without the need of a filter. This can avoid the problem of low filtration efficiency caused by the adhesion of suspended particles.
Keywords: Suspended Particle, Non-contact Purification Technology, Acoustic Levitation, Ultrasonic Acoustic Source, Microgravity Technology