EFFECT OF TURBULENCE DERIVED FROM INITIAL COMBUSTION OF INTERMITTENT SPRAY COMBUSTION ON MIXING AND CHEMICAL REACTION

间歇喷雾燃烧初燃湍流对混合和化学反应的影响

基本信息

批准号：
10650221
负责人：
YAMANE Koji
金额：
$ 1.92万
依托单位：
THE UNIVERSITY OF SHIGA PREFECTURE
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

The multidimensional engine simulation code, FREC-3D(CI), has been used to elucidate the effects of injection rate and split injection on diesel combustion, NO, and soot emissions. The combustion submodel has been updated, including the ignition submodel previously based on a one-step global mechanism. In-cylinder NO and soot formations were predicted by a Zeldovich mechanism with a partial equilibrium assumption and Morel's soot formation with an oxidation submodel, respectively. In result, computations give good agreement between measured and predicated trends of in-cylinder pressure, and rate of heat release, and a trade-off relationship between NO and soot emissions at pilot injection with high pressure injection. Computations also show that a high turbulence kinetic energy caused by a higher initial combustion is retained at the late combustion stage after fuel injection, and promotes the soot oxidation process.Experimental data suggests the roll of initial combustion on character … More istics of exhaust emissions. The experiment were carried out to change the initial combustion by using different nozzle orifice diameters and the electromagnetic controlled spool acceleration type injection system. It is found that smoke and NOx concentrations at smaller nozzle orifice diameter, I.e., dィイD2NィエD2 = 0.08mm, are higher than at bigger one, i.e., dィイD2NィエD2 = 0.14mm. The initial rate of heat release at dィイD2NィエD2 = 0.14mm is higher than that at dィイD2NィエD2 = 0.08mm. This means that the smaller orifice decreases the ignition delay at same injection pressure and controls rapid combustion at the initial stage. In generally, soot is formed at the late combustion stage. At late combustion stage, fuel injection is already terminated, so that combustion and spray at the initial stage have an influence on combustion at the late stage. So, the mixing by turbulence at late combustion stage is one key of important parameters for reduction of smoke, i.e., spray penetration, spray interaction by swirl, turbulent mixing of air and fuel, etc. The experimental results suggest that higher initial rate of heat release will enhance the mixing of soot and oxygen at late combustion stage. Less

多维发动机仿真代码FREC-3D（CI）已被用来阐明注射速率和分裂注射对柴油混合物，NO和烟灰排放的影响。组模型的组合已更新，包括基于一步全局机制的点火子模型。通过具有部分等效的Brium假设的Zeldovich机制预测了缸内NO和烟灰的形成，分别具有部分等效的Brium假设和莫雷尔的烟灰形成，并带有氧化子模型。结果，计算在测量和预测的缸内压力趋势与热量释放速率以及试点注射时NO与烟灰排放之间的权衡关系之间具有良好的一致性。计算还表明，在燃油注入后的晚期压缩阶段保留了由较高初始组合引起的高湍流动能，并促进了烟灰氧化过程。实验性数据表明，在特征上的初始组合卷……更多的排气排放量。进行实验以通过使用不同的喷嘴孔口和电磁控制的阀芯加速度注入系统来改变初始组合。发现在较小的喷嘴孔口直径（即D2Nie D2 = 0.08mm）处的烟雾和NOX浓度高于较大的烟雾，即D2Nie D2 = 0.14mm。 D2NIE D2 = 0.14mm时的最初热量释放速率高于D2NIE D2 = 0.08mm时的初始释放速率。这意味着较小的孔口会减少相同注入压力下的点火延迟，并控制初始阶段的快速压缩。通常，在压缩阶段形成烟灰。在后期压缩阶段，燃油喷射已经终止，因此初始阶段的压缩和喷雾会影响后期的燃烧。因此，晚期燃烧阶段的湍流混合是减少烟雾的重要参数的一个关键，即喷雾渗透，漩涡的喷雾相互作用，空气和燃料的湍流混合等等，表明较高的初始热量释放速率将增强晚期燃烧阶段的烟灰和氧气的混合。较少的