本研究以實驗方法探討空氣除塵槍加裝錐形多孔噴嘴，其錐形多孔噴嘴圓錐面傾斜角度、副噴嘴孔數、孔徑大小相對於主噴嘴所衍生噴流噪音之影響。以S25C低碳鋼製作出30度、40度、50度、60度圓錐面傾角，並垂直於圓錐面鑽削2孔數、4孔數、6孔數之副噴嘴口，而主噴嘴與副噴嘴孔徑均為3mm，總共分成4群噴嘴。實驗內容為觀察錐形噴嘴圓錐面傾斜角度、副噴嘴孔數、副噴嘴孔徑相對於主噴嘴抑制噴流噪音之影響，探討衝力、噪音、頻譜、及流速變化之趨勢與其相關特性，並與原噴嘴孔徑4.9mm之噴槍作比較分析。
實驗結果顯示，空氣除塵槍加裝錐形多孔噴嘴其整體衝力值約為原噴嘴孔徑4.9mm噴槍之一半。在噪音部分，當儲氣筒於8.2 kg∕cm^2滿壓的狀態，噪音計沿著4群噴嘴出口中心軸線距離X/D＝10～50增加，其整體4群噴嘴噪音分貝值介於91～94dB之間，當儲氣筒於6.4 kg∕cm^2重新增壓狀態，其整體4群噴嘴噪音分貝值介於88～91dB之間，4群噴嘴於高壓部分，降噪約2～3dB。在頻譜部分，麥克風距離噴嘴出口X/D＝10處，4群噴嘴有明顯峰值頻率存在，此峰值頻率範圍介於6000～8000Hz之間，麥克風距離噴嘴出口X/D＝20～50處，4群噴嘴峰值頻率往低頻移動，此峰值頻率範圍介於100～300Hz，由此可知，渦漩結構能量集中於高頻率部分。在流速部分，於儲氣筒8.2 kg∕cm^2滿壓狀態，孔徑4.9mm噴槍其平均流速可達到228.17m/s，約為4群錐形噴嘴平均流速1～2倍。

This study aims to analyze the connection between the air blow guns equipped with conical multiple nozzles and the variations of jet noise produced consequently. The main factors examined in this study include the inclination angle of the conical multiple nozzles, the number of by-pass orifices, and the diameter of by-pass orifices and the major nozzle orifice.
Made from low-carbon steel, the conical surfaces are categorized by four different Inclination angles ( 30°, 40°,50°and 60°), and different numbers of by-pass orifices (2, 4, and 6) are drilled perpendicularly to the conical surfaces. The diameters of both the major and each by-pass orifice are 3 mm. Experiments are carried out to observe the influence of the above mentioned factors on reducing jet noise, to analyze the variation of impinging force, noise, spectra, and jet velocity , and to examine the difference between air blow guns with 3mm conical multiple nozzles and the 4.9mm air blow guns without conical nozzles.
The results are as follows:
(1) Air blow guns with conical multiple nozzles produced the impinging forces half as much as those without conical nozzles.
(2) In terms of noise
(A) When the air container is charged to full pressure (8.2kg/cm^2) and the sound level meter moves along the central axis of the nozzle orifices within the distance between 30mm and 150mm (X/D=10~50), the sound noise detected increases as the meter gets closer to the orifices and falls between 91dB and 94 dB.
(B) When the air container is recharged with the pressure of 6.4kg/cm^2, the sound noise detected appears within the range between 88 and 91 dB. The noise reduces by 2 to 3 dB in the range of high pressure.
(3) In terms of spectra
(A) When the microphone is placed 30mm away from the nozzle orifices (X/D=10), significant peak frequencies are found in all the four kinds of nozzle orifices, ranging from 6,000 Hz to 8,000 Hz.
(B) When the microphone is placed at the distance from 60mm to 150mm away from the nozzle orifices (X/D=20~50), peak frequencies of all the four kinds of nozzle orifices plunge into the range between 100 Hz and 300 Hz. Thus, it can be inferred that the energy of vortex structure gathers mostly within the range of high frequency.
(4) In terms of jet velocity, when the air cylinder is charged to full pressure (8.2kg/cm^2), the average velocity of the 4.9 nozzle is 228.17m/s, roughly one or two times as fast as the average velocity of the four groups of the conical nozzles.

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(http://www.epa.gov.tw/main/index.asp)，查詢日期：2013年3月19日。
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