Effects of ultra-high injection pressure and micro-hole nozzle on flame structure and soot formation of impinging diesel spray
Effects of ultra-high injection pressure and micro-hole nozzle on flame structure and soot formation of impinging diesel spray
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DOI：
10.1016/j.apenergy.2010.11.035
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发表时间：
2011-05-01
期刊：
影响因子：
11.2
通讯作者：
Nishida, Keiya
中科院分区：
文献类型：
--
作者：
Wang, Xiangang;Huang, Zuohua;Nishida, Keiya
在定容燃烧室中，利用高速摄像技术研究了超高喷射压力（P-inj = 300 MPa）和微孔喷嘴（d = 0.08 mm）对柴油喷雾火焰结构和碳烟生成的影响。采用双色高温计测量了650和800 nm两个波长下的视距烟尘温度和浓度。垂直于喷嘴轴线的平壁位于距离喷嘴尖端30 mm处，以产生冲击喷雾火焰。使用100、200和300 MPa三种注射压力和直径为0.16和0.08 mm的两种注射器喷嘴。使用传统的喷嘴（0.16 mm），超高的喷射压力可显著降低碳烟的形成。当喷射压力为100 MPa时，采用0.08 mm的微孔喷嘴时，撞击火焰的尺寸明显减小，碳烟生成量降低。在200和300 MPa的喷射压力下，碳烟的形成太弱而不能用微孔喷嘴检测到。在消除喷油速率对碳烟水平的影响后，超高喷油压力和微孔喷嘴对碳烟的降低效果都比较明显。比较了常规喷嘴和微孔喷嘴撞击喷雾火焰和自由喷雾火焰的碳烟生成特性。对于常规喷嘴，平壁撞击显著恶化了碳烟的形成。而平壁对微孔喷嘴自由喷雾火焰的碳烟生成特性影响不大。0.16 mm喷嘴的液体长度大于冲击距离，0.08 mm喷嘴的液体长度小于冲击距离。与传统喷嘴的自由火焰相比，液体对壁面的撞击是造成撞击火焰的碳烟水平恶化的原因。(C)2010爱思唯尔有限公司版权所有。
The effects of ultra-high injection pressure (P-inj = 300 MPa) and micro-hole nozzle (d = 0.08 mm) on flame structure and soot formation of impinging diesel spray were studied with a high speed video camera in a constant volume combustion vessel. Two-color pyrometry was used to measure the line-of-sight soot temperature and concentration with two wavelengths of 650 and 800 nm. A flat wall vertical to the injector axis is located 30 mm away from the injector nozzle tip to generate impinging spray flame. Three injection pressures of 100, 200 and 300 MPa and two injector nozzles with diameters of 0.16 and 0.08 mm were used. With the conventional injector nozzle (0.16 mm), ultra-high injection pressure generates appreciably lower soot formation. With the micro-hole nozzle (0.08 mm), impinging spray flame shows much smaller size and lower soot formation at the injection pressure of 100 MPa. The soot formation is too weak to be detected with the micro-hole nozzle at injection pressures of 200 and 300 MPa. With eliminating the impact of injection rate on soot level, both ultra-high injection pressure and micro-hole nozzle have an obvious effect on soot reduction. Soot formation characteristics of impinging spray flame were compared with those of free spray flame using both the conventional and micro-hole nozzles. With the conventional nozzle, flat wall impingement deteriorates soot formation significantly. While soot formation characteristics of free spray flame with the micro-hole nozzle are not altered obviously by flat wall. Liquid length of the 0.16 mm nozzle is longer than the impingement distance and liquid length of the 0.08 mm nozzle is shorter than the impingement distance. Liquid impingement upon the wall is responsible for the deteriorated soot level of impinging flame compared to that of free flame with the conventional nozzle. (C) 2010 Elsevier Ltd. All rights reserved.