共查询到20条相似文献,搜索用时 78 毫秒
1.
应用单孔喷油器结合高速摄影技术研究了B5生物柴油和京标-10号柴油在不同喷油压力、环境温度和燃油温度条件下的喷雾特性,喷雾参数包括喷雾形态、喷雾贯穿距、喷雾贯穿速度和喷雾锥角.结果表明:两种燃油的喷雾贯穿距随时间几乎呈线性变化,喷射初期喷雾贯穿速度较大,且随着喷油压力的增加喷雾贯穿速度增加;随着时间的推移(油束的发展),喷雾贯穿速度逐渐下降,且较高的喷油压力下,喷雾贯穿速度下降趋势更加明显;在喷油压力和燃油温度相同时,随着环境温度从25℃升高到350℃,喷雾过程中的最大喷雾贯穿速度更大,且120 M Pa喷油压力下,最大喷雾贯穿速度可达400 m/s.在相同条件下,B5生物柴油油束蒸发持续时间较京标-10号柴油更长,表明生物柴油的加入使得B5生物柴油的沸点升高,相同温度下蒸发能力变差.比较相同条件下B5生物柴油和京标-10号柴油喷雾锥角,京标-10号柴油的喷雾锥角略大,这是由于京标-10号柴油黏度较小,液滴间作用力小,使得喷雾锥角增大. 相似文献
2.
3.
煤制油的生产工艺成熟、来源广泛,有利于降低我国对石油进口的依赖。通过定容燃烧弹进行了可视化研究,分析了煤制油在不同环境条件下的喷雾和着火特性。研究结果表明,煤制油喷雾和柴油喷雾在不同工况下均表现出良好的一致性,喷雾发展趋势相同。当环境温度保持500 K不变,随着环境压力由3 MPa提高到6 MPa,煤制油喷雾的贯穿距减小了22.67%,而喷雾锥角增大了46.9%。随着环境温度的提高,大量燃油液滴在破碎后迅速汽化,故喷雾贯穿距和喷雾锥角均表现出明显的降低趋势。在高环境压力下,煤制油的着火时刻提前,火焰浮起长度由38.8 mm缩短至30 mm,并表现出良好的球形火焰形态。与柴油相比,煤制油喷雾的贯穿距较短而锥角较大。在500 K,6 MPa的环境条件下,煤制油和柴油的喷雾贯穿距分别为46.4 mm和49.6 mm,表明煤制油在实际使用时更不容易产生撞壁现象。 相似文献
4.
5.
利用高速摄影技术,对空气辅助和无空气辅助两种典型的柴油机氮氧化物(NOx)选择催化还原(SCR)尿素喷射系统,在常温常压下的尿素喷雾特性和在定容燃烧弹内对空气辅助喷射系统在不同温度下的尿素喷雾特性进行了可视化试验研究.结果表明,随着尿素溶液喷射速率的提高,空气辅助喷射系统的喷雾贯穿距增大,喷雾锥角变小,且随着环境温度的上升贯穿距明显减小,发生碰壁现象的可能性减小;而无空气辅助喷射系统的喷雾形态则基本不受喷射速率的影响.应用粒子动态分析仪(PDA)对两种喷射系统的喷雾粒径分布进行的测试结果表明,空气辅助喷射系统的喷雾液滴粒径明显小于无空气辅助喷射系统,因而具有良好的喷雾特性. 相似文献
6.
为了研究燃料特性对喷雾特性的影响,试验配置了四种掺混不同含氧燃料的柴油,在环境背压为5 MPa,喷射压力分别为90 MPa、120 MPa和150 MPa的条件下,通过喷雾可视化装置对四种试验燃料的宏观和微观喷雾特性进行了研究。结果表明,在一定的喷射压力条件下,喷雾贯穿距离(STP)随着运动粘度、密度和汽化潜热的降低而减小,平均喷雾锥角(ASA)随着运动粘度和汽化潜热的降低而略有增大。喷雾贯穿距离和喷雾面积均随着喷射压力的升高而升高,喷雾锥角随着喷射压力的升高而略有下降,索特平均直径(SMD)也随着喷射压力的升高而下降。综合评价来看柴油掺混20%的2,5-二甲基呋喃(2,5-DMF)且在150 MPa喷射压力下的喷雾特性表现最好。 相似文献
7.
利用定容弹、纹影仪以及高速相机等装置,就柴油转子发动机工况下的喷雾过程进行了试验研究,重点分析了喷雾环境背压和喷射压力对喷雾特性的影响。结果表明:在转子发动机喷雾过程中,喷雾扩散速度先快速增大后逐渐减小;喷雾锥角在初次雾化阶段内急剧减小,然后在二次雾化作用下保持相对稳定。喷雾环境背压的增大,有效减小了喷雾贯穿距离,增大了喷雾锥角,说明喷雾环境背压的增大对喷雾贯穿距离和锥角都有显著的影响,从而为转子发动机喷油正时的优化提供了试验数据支持;随着喷射压力提高,喷雾贯穿距离和喷雾锥角都增大,并且增大喷射压力加强了燃油的初次雾化和二次雾化,有利于提高转子发动机喷雾质量,为优化柴油转子发动机油气混合状态创造了条件。 相似文献
8.
9.
10.
为探究喷射压力、温度、背压和交叉角对交叉孔喷嘴喷雾性状的影响,基于可视化定容弹系统,利用阴影法,研究了单孔与不同角度交叉孔喷嘴的喷雾特性。结果表明:与单孔喷嘴相比,交叉孔喷嘴的喷雾贯穿距较小,喷雾锥角较大,且随着交叉角的增大,差距更加明显;随着喷射压力的提高,交叉孔与单孔喷嘴的喷雾贯穿距的差别减小,交叉角较大的交叉孔喷嘴的喷雾锥角增大;低蒸发温度下,喷射压力对喷雾前期贯穿距的影响较大,随着蒸发温度升高,交叉孔与单孔喷嘴喷雾锥角差距增大,喷雾前期贯穿距差别减小;背压提高后,总的趋势是喷雾贯穿距缩短,而喷雾锥角增大;与单孔喷嘴相比,它对交叉孔喷嘴的喷雾特性影响更大。 相似文献
11.
Low heating value (LHV) of di-methyl ether (DME) is lower than that of diesel. To get the similar heat value with diesel from the diesel engine operation, single injection quantity of DME should be increased. This investigation was tried to increase the injection quantity of DME by the modified diesel injector and investigated the penetration length and spray angle of DME spray. DME was injected by using three-type modified diesel injectors those nozzle-hole diameters (Injector 1: 1.66 mm, Injector 2 and 3: 0.25 mm) and orifice diameters were different (Injector 1 and 2: 0.6 mm, Injector 3: 1 mm). Spray characteristics of DME was investigated with a various ambient pressures (2.5, 5.0 MPa) in the constant volume chamber and a fuel was injected by varied injection pressure from 35 to 70 MPa by interval of 5 MPa using a DME common rail fuel injection system. The result shows that DME injection quantity by Injector 3 was 1.69 ~ 2.02 times larger than that of diesel injection quantity by Injector 1. In this case, DME spray got the similar heat value compared with diesel spray. The penetration speed of DME spray by Injector 3 was the fastest, thus when the spray development was end, the penetration length of DME spray by Injector 3 was the longest compared with the other cases. In case of the spray angle, Injector 2 and 3 had the similar spray angle and these were larger than that of diesel and DME sprays by Injector 1. As the result, Injector 3 was the solution for how to solve the low heating value of DME. 相似文献
12.
二甲醚/柴油混合燃料在压燃式发动机上的应用 总被引:1,自引:0,他引:1
为探索二甲醚/柴油混合燃料作为柴油机替代燃料的应用性能,对D20二甲醚/柴油混合燃料的喷雾特性进行了试验研究;同时,开展了直喷式柴油机燃用二甲醚/柴油混合燃料动力性能、经济性能及排放性能研究。结果表明:在同样的环境背压下,D20混合燃料的油束与柴油相比较,贯穿度有所缩短,喷雾锥角有所增大;柴油机燃用二甲醚/柴油混合燃料时,通过适当调整循环油量,发动机的动力性可以超过原柴油机,最低当量比油耗下降4.5%,烟度指标下降70%以上,NOx排放降低30%~50%;二甲醚/柴油混合燃料是一种能实现高比功率、低排放的石油替代燃料。 相似文献
13.
14.
《JSAE Review》1999,20(3):407-411
Ignition and combustion characteristics of a two-stage injection diesel spray were experimentally investigated. A constant volume combustion chamber was filled with air which was controlled at 3.0 MPa and 743–923 K. In order to measure the ignition delay and the ignition position, a high speed video system was used. A 306 nm interference filter and an image intensifier system were attached to the camera for detecting the OH radical emission. The results show that the ignition delay of a two-stage injection spray becomes shorter compared with that of a single injection spray. The ignition positions of two-stage injection spray are observed nearer to the nozzle than that of single injection spray. Also, the temperature limit of complete combustion on a two-stage injection spray becomes lower than that of a single injection spray. 相似文献
15.
16.
Donghoon Kim Stephen Sungsan Park Choongsik Bae 《International Journal of Automotive Technology》2018,19(1):1-8
Three visualization methods, Schlieren, Shadowgraph, and Mie-scattering, were applied to compare diesel and gasoline spray structures in a constant volume chamber. Fuels were injected into a high pressure/high temperature chamber under the same in-cylinder pressure and temperature conditions of low load in a GDCI (gasoline direct injection compression ignition) engine. Two injection pressures (40 MPa and 80 MPa), two ambient pressures (4.2 MPa and 1.7 MPa), and two ambient temperatures (908 K and 677 K) were use. The images from the different methods were overlapped to show liquid and vapor phases more clearly. Vapor developments of the two fuels were similar; however, different liquid developments were seen. At the same injection pressure and ambient temperature, gasoline liquid propagated more quickly and disappeared more rapidly than diesel liquid phase. At the low ambient temperature and pressure condition, gasoline and diesel sprays with higher injection pressures showed longer liquid lengths due to higher spray momentum. At the higher ambient temperature condition, the gasoline liquid length was shorter for the higher injection pressure. Higher volatility of gasoline is the main reason for this shorter liquid length under higher injection pressure and higher ambient temperature conditions. For a design of GDCI engine, it is necessary to understand the higher volatility of gasoline. 相似文献
17.
《JSAE Review》1998,19(4):319-327
This study aimed to reduce NOx and soot by creating a more homogeneous lean fuel distribution in a diesel spray using high-pressure fuel injection and a micro-hole nozzle. This injection system shortened the ignition delay, but a homogeneous lean fuel distribution in the diesel spray was not achieved. Using a lower cetane number fuel, the resulting longer ignition delay made a uniform, lean fuel distribution in the diesel spray possible with this injection system. Ignition and combustion were analyzed by the combustion chamber pressure history, and flame temperatures and KL values were analyzed by the two-color method. 相似文献
18.
19.
U. B. Azimov K. S. Kim D. S. Jeong Y. G. Lee 《International Journal of Automotive Technology》2011,12(2):159-171
An experimental study has been performed on spray combustion and two-dimensional soot concentration in diesel (ULSD), GTL
and GTL-biodiesel fuel jets under high-pressure, high-temperature quiescent conditions. Instantaneous images of the fuel jets
were obtained with a high-speed camera. It was confirmed that by blending GTL with 20% rapeseed biodiesel, certain fuel properties
such as kinematic viscosity, density, surface tension, volatility, lower heating value and others may be designed and improved
to be more like those of conventional diesel fuel but with considerable decrease in the amount of sulfur, PAH, cold filter
plugging point, etc. The results showed that the spray tip penetration increased and the spray cone angle decreased when 20%
biodiesel fuel was added to GTL fuel. Autoignition of the GTL-biodiesel blend occurred slightly earlier than that of diesel
fuel. Experiments under high-pressure, high-temperature conditions showed that higher injection pressure induced a lower soot
formation rate. The integrated flame luminosity, which serves as an indicator of soot concentration in the fuel jet, was slightly
higher for the GTL-biodiesel blend than for pure GTL fuel due to the slightly higher sulfur content of pure biodiesel fuel. 相似文献