摘要
从提高射流利用率出发,在自振脉冲水射流喷嘴振荡腔上开孔自吸入空气,以形成一种自振脉冲气液射流,研究其振荡频率以及打击力的实际影响因素.基于水声学与流体动力学原理建立自振脉冲气液射流频率模型,并以悬臂梁为靶物,通过考察射流冲击悬臂梁时的振动特性获得其时域及频域特征.结果表明,自振脉冲气液射流的振荡频率随腔长增加单调递减,随含气率变化存在极小值,且在初始段发生骤变,实测值与理论值相吻合;对应自振脉冲气液射流产生最大谐振峰值的最优腔长略小于自振脉冲水射流,且前者最大谐振峰值较后者明显提高.
Aiming at improving the utilization ratio of jet,the self-excited oscillation pulsed air-water jet is generated by entraining air into the chamber of a self-excited oscillation pulsed water jet nozzle.The present studies focus on the actual influencing factors of oscillation frequency and hitting power of jet.Based on the theory of hydro-acoustics and fluid dynamics,a theory model which describes frequency characteristic of the self-excited oscillation pulsed air-water jet is presented.Moreover,the time domain and frequency domain characteristics of jet can be obtained by testing the vibration of cantilever beam with equalized strength caused by the jet impinging.The calculation result of the model show that the oscillation frequency of self-excited oscillation pulsed air-water jet monotonously decreases with increasing the cavity length,the relation between frequency and air hold-up is not always decreasing monotonously,but begins to go up after the minimal value.However,the sudden change of the model curve occurs at a given very low air hold-up.The theoretical result is confirmed well by experiment;it is also found that the optimal chamber length corresponding to the maximum resonance peak of the self-excited oscillation pulsed air-water jet is slightly smaller than that of the self-excited oscillation pulsed water jet,and the maximum resonance peak of the former is much higher than that of the latter.
出处
《力学学报》
EI
CSCD
北大核心
2013年第4期534-540,共7页
Chinese Journal of Theoretical and Applied Mechanics
基金
湖南省科技计划项目(2013SK3165)
湖南省自然科学基金项目(13JJ9013)
湖南省教育厅科研项目(12C0066)资助~~
关键词
自振脉冲气液射流
腔长
含气率
振荡频率
峰值
self-excited oscillation pulsed air-water jet
cavity length
air hold-up
oscillation frequency
peak value
