基于局域波分解的循环射流混合槽内压力脉动信号时频特性分析  

Analysis of the time-frequency attributes of pressure fluctuation signals in a circulating jet tank based on local wave decomposition

作　　者：禹言芳[1] 吴剑华[1] 孟辉波[1] 

机构地区：[1]沈阳化工大学能源与动力工程学院辽宁省高效化工混合技术重点实验室,沈阳110142

出　　处：《北京化工大学学报（自然科学版）》2012年第6期23-30,共8页Journal of Beijing University of Chemical Technology(Natural Science Edition)

基　　金：国家自然科学基金(21106086);辽宁省高等学校优秀人才计划(LJQ2012035);教育部科学技术研究重点项目(212030)

摘　　要：为了探讨循环射流混合槽射流混合区内瞬态流动特性,在Re=3660～32940范围内利用动态数据采集系统对射流混合区内不同轴向、径向和周向位置的瞬态脉动压力进行了测量,并采用基于局域波分解的方法分析了循环射流混合槽内压力脉动信号的时频分布。研究表明:瞬态压力波动信号的波动能量分布随瞬时频率的提高明显降低;在θm=π/6和π/3时,频率集中分布在为0～0.25 Hz,而θm=π/4和θm=5π/12时,瞬时波动频率主要分布在0～6Hz和0～20Hz。低雷诺数下流体运动随机性频繁,Re=3660时存在32Hz,25Hz,7Hz和5Hz等多个频率集中分布段,而Re=18300和Re=25620时频率范围为0～8 Hz和0～3 Hz。随着测量位置z/H增加,0～1 Hz内低频能量比例先减小然后增加再减少;z/H=0.85时受到自由液面的影响,集中能量频率分布范围较其他轴向位置要广,且0～5 Hz低频能量比例减少。In order to investigate the instantaneous flow characteristics in the jet mixing zones of a circulating jet tank（CJT）,a dynamic data acquisition system was employed to measure the instantaneous pressure fluctuation signals（PFS） in the Reynolds number（Re） range 3660-32940,at different axial,radial and circumferential positions.Frequency spectra were evaluated based on the local wave decomposition.The fluctuation energy distribution of instantaneous PFS was found to decrease markedly with increasing instantaneous frequency.For positions θm = π/6 and θm = π/3 the energy distributions were in the range 0-0.25 Hz,while it was in the range 0-6 Hz and 0-20 Hz for θm = π/4 and θm = 5π/12,respectively.The degree of fluid irregularity increased at low values of Re.Four concentrated energy bands at 32 Hz,25 Hz,7 Hz and below 5 Hz existed for Re=3660.However the energy was distributed in the range 0-8 Hz and 0-3 Hz for Re=18300 and Re=25620,respectively.With increasing values of z/H,the energy ratio in the range 0-1 Hz initially decreased,then increased and finally decreased again.The energy was distributed in a relatively wide frequency brand affected by the free liquid for z/H=0.85 and the energy ratio at low frequency（0-5 Hz） decreased.

关 键 词：局域波分解 循环射流混合槽 压力波动信号 WIGNER分布 频谱 

分 类 号：TQ050.5[化学工程]