Flame structure of wall-impinging diesel fuel sprays injected by group-hole nozzles
Flame structure of wall-impinging diesel fuel sprays injected by group-hole nozzles
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DOI：
10.1016/j.combustflame.2009.01.014
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发表时间：
2009-06-01
影响因子：
4.4
通讯作者：
Matsumoto, Yuhei
中科院分区：
文献类型：
--
作者：
Gao, Jian;Moon, Seoksu;Matsumoto, Yuhei
本文描述了在柴油机典型的实验条件下，在定容燃烧室中，对群孔喷嘴喷射的柴油喷雾碰壁火焰结构的研究。特别强调了两个孔之间的夹角（015度）的影响。在不同的模拟发动机负荷条件下的火焰结构和燃烧特性的研究）。采用激光吸收散射（LAS）技术对喷雾和混合气的特性进行了分析.直接火焰成像和OH化学发光成像被用来量化点火延迟，火焰几何参数，和OH化学发光强度。结果表明，在较大夹角和较高发动机负荷条件下，群孔喷嘴喷雾中出现了不对称的火焰结构，这与LAS观察到的喷雾形态一致。与基本喷嘴相比，大夹角的群孔喷嘴产生更高的OH化学发光强度，更宽的火焰区域，以及更大比例的高OH强度，意味着更好的燃料/空气混合和改善的燃烧特性。在高负荷工况下，群孔喷嘴的优势更加明显。在此基础上，探讨了群孔喷油嘴应用于实际直喷式柴油机的可行性。结果表明，群孔喷嘴喷雾的非对称火焰结构有利于在较宽的负荷范围内减少碳烟的生成。然而，群孔喷嘴的孔结构应仔细考虑，以实现适当的空气利用在燃烧室中。化学计量比柴油机燃烧是群孔喷嘴的另一个很有前途的应用。(C)2009燃烧研究所。爱思唯尔公司出版All rights reserved.
This paper describes an investigation of the flame structure of wall-impinging diesel sprays injected by group-hole nozzles in a constant-volume combustion vessel at experimental conditions typical of a diesel engine. The particular emphasis was on the effect of the included angle between two orifices (015 deg. in current study) on the flame structure and combustion characteristics under various simulated engine load conditions. The laser absorption scattering (LAS) technique was applied to analyze the spray and mixture properties. Direct flame imaging and OH chemiluminescence imaging were utilized to quantify the ignition delay, flame geometrical parameters, and OH chemiluminescence intensity. The images show that the asymmetric flame structure emerges in wall-impinging group-hole nozzle sprays as larger included angle and higher engine load conditions are applied, which is consistent with the spray shape observed by LAS. Compared to the base nozzle, group-hole nozzles with large included angles yield higher overall OH chemiluminescence intensity, wider flame area, and greater proportion of high OH intensity, implying the better fuel/air mixing and improved combustion characteristics. The advantages of group-hole nozzle are more pronounced under high load conditions. Based on the results, the feasibility of group-hole nozzle for practical direct injection diesel engines is also discussed. It is concluded that the asymmetric flame structure of a group-hole nozzle spray is favorable to reduce soot formation over wide engine loads. However, the hole configuration of the group-hole nozzle should be carefully considered so as to achieve proper air utilization in the combustion chamber. Stoichiometric diesel combustion is another promising application of group-hole nozzle. (C) 2009 The Combustion Institute. Published by Elsevier Inc. All rights reserved.