邢小伟,贾迎军,赵晓晓,孙楠楠,王恩浩,江楠,李国祥  

    摘要：本文采用数值模拟的方法对某柴油机燃烧过程进行了研究,通过与试验的对比获得了可信的计算模型,基于确立的计算模型设计了9种不同的后喷喷射策略,分析了后喷喷油量及主后喷间隔角对排放性能及缸内流动燃烧的影响。结果表明:在一定范围内,随着后喷量和主后喷间隔角的增加,缸内燃烧放热规律及温度曲线的峰值降低,NOx排放降低。适当增大主后喷间隔角,加强了主后喷间隔期缸内气流的运动,能够促进Soot的氧化,但当间隔角过大时,一方面降低了缸内温度,另一方面使部分Soot扩散到活塞与缸套夹缝处,导致Soot难以氧化,致使Soot生成量增大。

    关键词： 后喷;排放物;数值模拟

    Abstract: The process of spray and combustion of a diesel engine was simulated and the simulated results agrees well with the experiment data.Nine types of post injection strategy were designed.The emissions and the flow in cylinder which are caused by different amount of post injection diesel and time between the main injection and post injection were studied.The results show the peak of heat release and temperature decreased with the amount of post injected fuel and the separation between main injection and post injection grows within a range.The oxidation of Soot was promoted through the flow between the main injection and post injection,but if the separation between main injection and post injection was too large,the temperature will decrease and some of Soot diffuse into crevice between the piston and cylinder liner,making the oxidation difficult.

    Keywords: Post Injection;Emissions;Numerical Simulation

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