充量温度对某中速柴油机燃烧和NO_x排放的影响  

The influence of charge temperature on the combustion and NO_x emission of a medium speed diesel engine

作　　者：冷先银[1] 魏胜利[1] 田江平[2] 何爽[2] 隆武强[2] 郭海娥 张旭东 钟兵 李焕英 

机构地区：[1]江苏大学汽车与交通工程学院,江苏镇江212013 [2]大连理工大学内燃机研究所,辽宁大连116023 [3]陕西柴油机重工有限公司,陕西兴平713100

出　　处：《哈尔滨工程大学学报》2014年第11期1351-1357,共7页Journal of Harbin Engineering University

基　　金：国家科技支撑计划资助项目(2012BAG02B00);江苏省自然科学基金资助项目(BK20130514);江苏大学高级专业人才科研启动基金资助项目(12JDG080)

摘　　要：为了研究米勒循环条件下充量温度的变化对某中速柴油机燃烧和NOx排放的影响,采用三维计算流体动力学模拟方法对其缸内流动、喷雾、燃烧和NOx生成过程进行了数值模拟分析。结果表明:随着充量温度的降低,着火滞燃期、预混合燃烧放热率峰值和最高压力升高率不断增加,在充量初始温度比原机降低40 K之后尤为显著;指示油耗率和NOx排放率先降低后升高,说明过低的充量温度不利于降低NOx排放,其原因是滞燃期太长,预混合燃烧放热太多,促进了热NOx生成。In order to investigate the influence of charge temperature on the combustion and nitrogen oxide （ NOx ） emission of a medium speed diesel engine under Miller cycle, three-dimensional computational fluid dynamic modeling was performed to simulate the in-cylinder flow, spray, combustion and NOx formation processes. The s：mulation results showed that, as the charge temperature decreases, the ignition delay, peak heat release rate of premixed combustion stage, and maximum pressure rise rate continuously increase, especially, at the point when the charge temperature decreases 40 K or more lower than that of the original engine. However, the indicate,t specific fuel consumption rates and NOx emission rates both decrease first and then increase. The results indicated that the overly lowered charge temperature is not beneficial to the reducing of NOx emission, because the exce.,.sively prolonged ignition delay results in too much heat released in the premixed combustion stage, which accelerate the formation of thermal NOx.

关 键 词：柴油机 中速 燃烧 NOX排放 数值模拟 米勒循环 充量温度 

分 类 号：TK421[动力工程及工程热物理—动力机械及工程]