航空学报 > 2022, Vol. 43 Issue (3): 125212-125212   doi: 10.7527/S1000-6893.2021.25212

压比对文氏管汽蚀动态过程演变的影响

梁涛, 崔朋, 成鹏, 李清廉, 张彬, 宋杰   

  1. 国防科技大学 空天科学学院 高超声速冲压发动机技术重点实验室, 长沙 410073
  • 收稿日期:2021-01-05 修回日期:2021-01-19 出版日期:2022-03-15 发布日期:2021-03-26
  • 通讯作者: 李清廉 E-mail:peakdreamer@163.com
  • 基金资助:
    国家自然科学基金(11902351)

Influence of pressure ratio on evolution of cavitation dynamic process in Venturi tube

LIANG Tao, CUI Peng, CHENG Peng, LI Qinglian, ZHANG Bin, SONG Jie   

  1. Science and Technology on Scramjet Laboratory, College of Aerospace Science and Technology, National University of Defense Technology, Changsha 410073, China
  • Received:2021-01-05 Revised:2021-01-19 Online:2022-03-15 Published:2021-03-26
  • Supported by:
    National Natural Science Foundation of China (11902351)

摘要: 基于高速摄影和高频压力测量技术,对半矩形文氏管开展了酒精汽蚀试验,获得了汽蚀区域的流场结构和高频压力数据,基于标准差法分析了汽蚀区长度与压比的关系,基于图像和压力信号研究了汽蚀区的动态演变规律和压力振荡特性。结果表明:压比越小,汽蚀区发展越充分,且汽蚀区长度与压比呈负相关关系。汽蚀区动态特性由湍流脉动和折返射流机制主导,当压比较大时,湍流脉动主导了汽蚀区的动态行为,汽蚀区可分为发展区、融合区、溃灭区;压比较小时,折返射流主导了汽蚀区的动态行为,汽蚀区可分为发展区、回流区、溃灭区。发展区汽蚀形态稳定,能抑制下游压力波向上游的传递;湍流脉动和折返射流会造成发展区后方区域脱落云团的生成,并给下游带来压力振荡,振荡主频呈现出频带特征;低背压时,脱落云团将移动至扩散段下游更远区域,较大逆压梯度将造成脱落云团的逆行,使得扩散段存在局部回流区。

关键词: 半矩形文氏管, 汽蚀, 可视化, 动态过程, 压比, 液体火箭发动机

Abstract: Alcohol cavitation experiments were carried out on a semi-rectangular Venturi tube based on high-speed photography and high-frequency pressure measurement technology.The flow field structure and high-frequency pressure data of the cavitation area were obtained via the standard deviation method, and the dynamic evolution law and pressure oscillation characteristics of the cavitation area were studied based on the picture and pressure signals.The results show that the smaller the pressure ratio is, the more fully the cavitation region develops, and there is a negative correlation between the length of cavitation region and the pressure ratio.The dynamic characteristics of the cavitation region are dominated by the turbulence fluctuation and re-entrant jet mechanism.With a high pressure ratio, the turbulence fluctuation dominates the dynamic behavior of the cavitation zone which can be divided into the developing zone, fusion zone and collapse zone.When the pressure ratio is small, the re-entrant jet dominates the dynamic behavior of the cavitation region, and the cavitation region can be divided into the developing zone, recirculation zone and collapse zone.The development zone is stable and can inhibit the transmission of the downstream pressure wave toward the upstream direction; the turbulence fluctuation and re-entrant jet will cause the formation of falling cloud clusters in the rear area of the development zone, thereby bringing pressure oscillation to the downstream area, with the main frequency of the oscillation exhibiting characteristics of the frequency band; when the back pressure is low, the falling cloud cluster will move further downstream in the diffusion zone, and the larger reverse pressure gradient will cause retrogradation of the falling cloud cluster, forming a local recirculation zone in the diffusion section.

Key words: semi-rectangular Venturi tube, cavitation, visualization, dynamic process, pressure ratio, liquid rocket engine

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