本研究探討內混式氣助式霧化器在不同出口面積及不同漩渦腔（Swirling chamber）長度，以及在噴嘴內配置中心體（Center body）後，其對霧化特性之影響。所使用之霧化器分別為P型霧化器（P-1、P-2、P-3霧化器）與N型霧化器（N-1、N-2、N-3霧化器），探討不同結構下之霧化器其霧化特性，噴霧之粒度分布以Malvern公司雷射繞射式RT-Sizer粒徑分析儀量測。
　　研究結果顯示，當霧化器使用P型霧化器時，在噴嘴出口面積為12.57mm2（P-3霧化器）時，會有較小之噴霧平均粒徑（SMD）與粒徑分布標準差（σ）。例如在液體壓力3.0 bar，氣體壓力4.5 bar下，P-1霧化器所產生噴霧之噴霧平均粒徑為4.68μm，噴霧粒徑分布標準差為16.93μm；P-2霧化器之噴霧平均粒徑則為3.52μm，噴霧粒徑分布標準差為8.54μm；而使用P-3霧化器實驗，噴霧之噴霧平均粒徑即可大幅縮減至3.00μm，噴霧粒徑分布標準差亦可降至5.69μm。將噴嘴出口面積從3.14 mm2加大至12.57 mm2時，噴霧平均粒徑由4.68μm降低至3.00μm減小了36%，而噴霧粒徑分布標準差由16.93μm降低至5.69μm下降了66%，這表示面積參數為一種有效之霧化控制機構。利用增加出口面積之方式，來提高霧化能量，使得噴霧顆粒粒徑降低，同時也促進噴霧顆粒分布窄化，對於工程上需要微小化及窄化噴霧之場合，這是甚佳之應用。
　　進一步改變噴嘴內部結構而使用N型霧化器，由研究結果顯示，N-1霧化器在噴霧平均粒徑與霧化粒子之粒度分布方面均優於N-2與N-3霧化器，這表示霧化器內部配置中心體去提供一個表面積讓液體附著，且中心體與渦漩腔的管壁所形成之流道易使液體與霧化氣體之間產生一較高之相對速度，因此，霧化器內部加裝中心體對霧化效能是有所提昇，而當渦漩腔的加長無助於霧化效能的提昇，反而減慢了液體與霧化氣體之間的相對速度，而使的霧化後的粒子產生較多之大顆粒，而使得霧化效果變差。例如在液體壓力3.0 bar，氣體壓力4.5 bar下，N-1霧化器所產生噴霧之噴霧平均粒徑為3.77μm，噴霧粒徑分布標準差為9.58μm；N-2霧化器之噴霧平均粒徑則為4.03μm，噴霧粒徑分布標準差為10.62μm；而使用N-3霧化器之噴霧平均粒徑則為4.76μm，噴霧粒徑分布標準差為19.56μm，因此，在噴嘴內部加裝一中心體時，可以使噴霧平均粒徑從4.76μm降至 3.77μm下降21%，而噴霧粒徑分布標準差從19.56μm降至9.58μm下降51%。

　　This research program investigates the atomization characteristics of the internal mixing atomizer under different design configurations. The design parameters include the orifice diameter, the swirler and the center body, etc. The atomizers are designed P-type atomizers (i.e., P-1、P-2、P-3 atomizers) and N-type atomizers (i.e., N-1、N-2、N-3 atomizers). The effects of these design parameter on the atomization performance are described. Malvern RT-Sizer measures the particle size of the spray.
　　Results show that P-type atomizer with large orifice area produces spray with fine particle size and narrow size distribution. As a typical example, spray with (SMD, σ)=(4.68,16.93) μm can be obtained using P-1 atomizer under a liquid pressure of 3.0bar and gas pressure of 4.5bar. Furthermore, (SMD, σ)=(3.52, 8.54)μm and (SMD, σ)=(3.00, 5.69)μm can be aliened P-2 and P-3 atomizers, respectively. The enhanced atomization performance by increasing orifice area is due to the increase in gas-to-liquid mass ratio.
　　Results also show that the N-1 atomizer with center body has better performances than N-2 and N-3 atomizer. This indicates that the atomizer with center body can produce fine droplets and narrow size distribution. The atomizer with longer swirling chamber degrades the atomization performance. As a typical example, spray with (SMD, σ)=(3.77, 9.58)μm can be achieved using N-1 atomizer under liquid pressure of 3.0bar and gas pressure of 4.5bar. The cases of N-2 and N-3 atomizer (SMD, σ)=(4.03, 10.62)μm, (SMD, σ)=(4.76, 19.56)μm respectively. Hence the design of atomizer with center body can be used to enhance the atomization performance.

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