柴油机燃烧室气体振荡的模拟与试验研究  

Simulation and Experiment Research on Pressure Oscillation in Combustion Chamber of Diesel Engine

作　　者：李小倩[1] 舒歌群[1] 韦静思[1] 马维忍[1] 卫海桥[1] 

机构地区：[1]天津大学内燃机燃烧学国家重点实验室,天津300072

出　　处：《内燃机工程》2011年第6期86-92,共7页Chinese Internal Combustion Engine Engineering

基　　金：国家自然科学基金项目(50476065)

摘　　要：基于燃烧数学模型中的流场模型,对柴油机燃烧过程中的气体高频声波振荡问题建立声学模型并给出了求解方法。用该方法对燃烧室内的声学变化特性进行计算,并将不同转速和不同负荷工况下的实测缸压振荡结果和声学计算结果进行对比。研究结果表明:该方法能正确计算柴油机燃烧过程中的压力振荡。对于试验用柴油机,燃烧室气体第一阶主振荡频率均在5kHz以上,振荡规律与具体的工况有关。直接影响燃烧振荡性质的两个因素为放热速率和燃气温度,燃气温度越高,则发生振荡时的振荡频率越高;放热规律曲线峰值越大则振荡幅值越大。以8×10-5 s为间隔绘制了声场分布图,结果表明:燃烧室中的声场分布是不均匀的,且随时间变化十分迅速。Based on the numerical flow field model of combustion, an acoustic model was established for gas high-frequency acoustic oscillations in combustion process of diesel engine, and its solution method was given out. The measured experimentally cylinder pressure oscillation curves in different conditions of speed and load were compared with corresponding calculated acoustic characteristic data of the gas in combustion chamber. It shows that this method can correctly predict combustion pressure oscillations. For the diesel engine studied in the paper, all of the first-order main oscillation frequencies are above 5 kHz and the oscillation regularities are dependent on specific operation conditions. Heat release rate and gas temperature in the chamber are the two factors directly influencing oscillations characteristics, the oscillation frequencies rise with the temperature increasing, and the oscillation amplitudes ascend with the heat release rate peak rising. Finally, the contours of acoustic field were drawn with time interval of 8×10^-5S. Obviously, the acoustic field distribution is inhomogeneous and varies rapidly with time.

关 键 词：内燃机 柴油机 燃烧 气缸压力 声压 高频振荡 

分 类 号：TK421.2[动力工程及工程热物理—动力机械及工程]