共查询到19条相似文献,搜索用时 370 毫秒
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KIVA程序是一功能比较齐全的内燃机缸内过程模拟数值计算的大型程序,它代表了目前多维模型的最新进展。本文论述了KIVA程序中喷雾模型的发展历程和进展,最后指出了燃油喷雾多维模型研究的发展趋向。 相似文献
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阐述了闪急沸腾喷雾的基本原理,通过比较分析闪急沸腾喷雾与传统喷雾的差异,指出闪急沸腾喷雾是一种极具潜力的燃油喷射方式;论述了近年来国内外对过热燃油和溶气燃油闪急沸腾喷雾研究的进展与现状,介绍了过热液体闪急沸腾喷雾的数学模型及其发展,并从理论上分析了影响闪急沸腾喷雾的因素;展望了闪急沸腾喷雾的应用前景以及进一步研究的发展方向。 相似文献
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M. Xu Y. C. Sun Y. Cui K. Y. Deng L. Shi 《International Journal of Automotive Technology》2016,17(1):109-118
In diesel engine, spray penetration is usually changed by in-cylinder gas flow. Accurate prediction on diesel spray with gas flow is important to the optimal design of diesel fuel injection system. This paper presents a theory investigation focusing on the penetration of diesel spray with gas flow. In order to understand the effect of gas flow on the penetration of diesel spray, a one-dimensional spray model is developed from an idealized diesel spray, which is able to predict the spray behavior under different gas flow conditions. The ambient gas flow is simplified as ideal flow that has only constant flow velocity along x-axial and y-axial directions of spray. The x-axial and y-axial directions are respectively defined as along and vertical spray directions. The main assumption is that the y-axial direction gas flow has no effect on the penetration of spray along x-axial direction. The principles of conservation of mass and momentum are used in the derivation. Momentum of in-cylinder air flow is also taken into consideration. Validation of the model at stable condition is achieved by comparing model predictions with experimental measurements of diesel spray without gas flow from Naber's experiments. Furthermore, CFD simulations on penetration of diesel spray with gas flow were performed with the commercial code AVL-fire. The onedimensional model is validated by the penetration results with gas flow from CFD calculation. Results show that a reasonable estimation of the spray evolution can be obtained for both with and without ambient gas flow conditions. 相似文献
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利用高速摄影研究二甲基醚的喷雾特性 总被引:2,自引:1,他引:2
本文利用高速摄影技术在定容压力室中,通过6孔电磁喷射器,研究了二甲基醚(DME)的喷雾特性。结果表明,二甲基醚的喷雾射程随着定容压力室内气体压力的增加而减少;喷雾锥角则随和的升高而增大,在相同的条件下,二甲基 喷射锥角大于 喷射锥角;喷雾射程则低于柴油的喷雾射程。Hiroyasu喷雾射程的计算模型,通过适当的系数修正可以用于DME喷雾射程预测,由于DME喷雾射程和着火延迟期都比柴油短,在屐机缸内着火时刻,柴油的喷雾射程约为DME的2倍,从高速摄影的喷雾影像中可以清楚的看到,DME的蒸发速度明显比柴油快。 相似文献
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This paper proposed a quasi-dimensional combustion model from a new observed two-phase penetration and combustion phenomenon in diesel spray. In the model, fuel spray was divided into two of liquid and gas phase areas. Considering the phenomenon that separation of gas and liquid phase in diesel spray occurs during spray penetration, gas and liquid area of spray are discretized respectively. Liquid phase areas play important role in fuel mass transport, however gas phase areas are the main region for fuel combustion in the model. Fuel and air mixing rate of gas phase zone is the key for the calculation of combustion rate. Validation experiments are designed by using optimal Latin hypercube design method. Comparison of calculations and experiments show that the model is able to predict diesel engine performance at different engine speeds, loads, and injection pressure and timing, and provides guidance for the design of engines. 相似文献
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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
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以Hiroyasu喷雾和燃烧模型为基础,建立了适应不同海拔环境的特种车辆增压柴油机模型,并利用平原台架试验和海拔3 700 m实车试验对计算结果进行了验证。计算了该柴油机在0~5 000 m海拔实际运行时的动力性、经济性和排放性,预测了不同环境下柴油机热负荷、机械负荷主要参数的变化规律。结果表明,当海拔高度为5 000 m时,柴油机动力性、经济性比平原恶化10%以上;柴油机缸内燃烧温度峰值上升235℃以上,涡前排气温度最多增加150℃左右;最大压升率比平原升高15%以上,NOx排放减少,碳烟排放剧增。 相似文献
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发动机燃用水乳化柴油的研究进展 总被引:1,自引:0,他引:1
综述了柴油机燃用水乳化柴油的燃烧与喷雾特性、动力性与经济性及排放特性,对比分析了发动机燃用水乳化柴油与普通柴油在性能上的差异及其原因,总结了水乳化柴油在柴油机上的应用优化方法。结果表明:与柴油相比,乳化柴油着火滞燃期延迟,燃烧持续期缩短,喷雾贯穿距变长或相差不大,火焰升起高度增加;燃用乳化柴油时动力性下降,但有效热效率较柴油升高;乳化柴油可以明显降低NOx和炭烟排放,但多数工况下HC和CO排放有所升高,低转速和中低负荷工况下尤为明显;燃用乳化柴油时颗粒物数量浓度增加,体积浓度减小,且对于醛类和噪声排放并没有改善作用;添加合适添加剂或结合发动机技术协同作用,可以针对性地改善乳化柴油的燃烧过程,进一步起到节能减排的效果。基于燃料稳定性与燃料理化特性综合优化目标的燃料设计,以及适用于乳化柴油的高压共轨柴油机燃烧组织参数优化是未来的研究方向。 相似文献