旋杯式霧化器之噴霧性研究

Abstract

旋杯式霧化器已廣泛應用於噴漆、乾粉製程等工業應用上，此種旋杯噴霧有著涵蓋面積廣、液滴速度快與液滴傳遞效率較傳統噴嘴式噴霧器高等優點。應用在電子散熱上，預期會有不錯的效能也將可能取代陣列噴嘴式的噴霧散熱。本研究計畫將使用水為測試流體，探討黏性較低的流體應用在此類噴霧器上之物理現象。我們利用實驗的方式，搭配全域液滴粒徑速度儀(GSV)的量測技術。觀察在不同實驗條件下，液滴的分佈、數量、速度與粒徑。實驗中我們採用兩個直徑皆為50mm，內壁開口角度分別為0 度與45 度的鋁合金材質旋杯，並利用電動變頻馬達驅動旋杯，在3000到12000rpm 的轉速域分別注入流量9 與18 l/h 的水。透過全域式液滴粒徑速度儀量測後獲取液滴速度、粒徑之分布與整個空間中之液滴密度分布之數據。結果顯示，隨著旋杯轉速升高，噴霧粒徑分布區間會變得狹窄，而速度分布則會因為旋杯上液膜的滑動現象造成分布變得分散。此研究為日後旋杯式噴霧熱傳研究之前置實驗與初步探討，希望能夠增進對此種形式之噴霧器的了解與有效的控制其產生的噴霧之液滴大小與速度。以利往後的研究與實際應用上的精進。

The rotary atomizer is widely used in industrial applications such as painting and powder production. This method in industry is better than traditional nozzle spray because of wider spray area, higher speed of droplets, and higher efficiency of droplets transfer. In the category of electronic heat dissipation, favorable performance using the rotary atomizer can be applied for the spray cooling. This research used water as the working fluid and investigated the physical phenomenon of low viscosity liquid. Global sizing velocimetry system was used to measure the diameter, velocity, and number of spray droplets under different parameters. There were two types of rotary atomizer cups in the experiment. These aluminum alloy rotary cups had the diameters of 50mm. Regarding the cup geometry, one cup exhibited 0 degree and the other cup exhibited 45 degree between inner face and outer face of the cup. A motor and an inverter were employed to control the rotary speed between 3000rpm and 12000rpm, and the injected water flow rates were 9l/h and 18l/h. The results from the current research can be used for future development of the rotary atomizer.