基于小波包的二甲醚发动机复合燃烧爆震能量分析
李帅博，尹发辉，胡文帅，侯军兴*
郑州航空工业管理学院航空宇航学院，河南 郑州 450046
摘要：为更好地检测判别二甲醚发动机复合燃烧爆震，试验研究复合燃烧中正常燃烧和爆震燃烧时缸内压力在各个频带的小波包能量分布，确定爆震燃烧时缸内压力的敏感频带，分析不同平均有效压力、不同发动机循环爆震燃烧时缸内压力在各个频带的小波包能量和能量熵分布。结果表明：正常燃烧时，缸内压力升高，加速度的波动幅值和各频带的小波包能量均很小；爆震燃烧时，缸内压力升高，速度波动幅值显著增大，波动时刻提前，各频带的小波包能量不同程度增大，爆震敏感频带频率为7.50~8.75 kHz的小波包能量显著增大;爆震燃烧时，不同平均有效压力、不同循环发动机缸内压力各频带的小波包能量、能量熵的分布规律相似，燃烧状态决定了小波包能量分布和能量熵分布，平均有效压力和循环对其分布无影响。
关键词：二甲醚；复合燃烧；爆震；小波包；能量熵
Knock energy analysis of compound combustion in a DME engine based on wavelet packet
LI Shuaibo, YIN Fahui, HU Wenshuai, HOU Junxing*
School of Aerospace Engineering, Zhengzhou University of Aeronautics, Zhengzhou 450046, China
Abstract：In order to better detect the engine knock of compound combustion, the wavelet packet energy distribution characteristics of the in-cylinder pressure with normal combustion and knocking combustion in DME compound combustion are studied experimentally, and the sensitive frequency band of knocking combustion is determined. The wavelet packet energy and energy entropy distribution of cylinder pressure in various frequency bands under different average effective pressures and different engine cycles of detonation combustion are analyzed.The results show that the fluctuation amplitude of in-cylinder pressure rise acceleration and wavelet packet energy during different frequency band are very small with normal combustion. During knocking combustion, the fluctuation amplitude increases significantly, the beginning timing of fluctuation advances. The wavelet packet energy of each frequency band increases, especially that of the energy of wavelet packets with detonation sensitivity frequency bands ranging from 7.50 to 8.75 kHz increases significantly.During knocking combustion, the distribution characteristics of wavelet packet energy and energy entropy in each frequency band are similar with different brake mean effective pressure and different engine cycles. The combustion state determines the wavelet packet energy distribution and energy entropy distribution, and the effects of the brake mean effective pressure and engine cycle on the distributions are no obvious.
Keywords:dimethyl ether; compound combustion; knock; wavelet packet; energy entropy
