法向声场中粘弹性平面液膜的线性不稳定性研究
Linear Instability of a Viscoelastic Planar Liquid Sheet in the Presence of Transverse Acoustic Field
贾伯琦 1于卓民 2刘宇新 3虞育松2
作者信息
- 1. 北京交通大学机电学院,北京 100044;北京交通大学唐山研究院,唐山 063000
- 2. 北京交通大学机电学院,北京 100044
- 3. 北京航天微系统研究所,北京 100094
- 折叠
摘要
针对液体火箭发动机中可能出现的声学振荡工况,对法向声场中平面液膜的线性不稳定性进行了理论分析.采用粘势流理论,描述了液膜的动量方程和边界条件.基于Floquet理论,获得了正弦、曲张双模态耦合的色散方程.结果表明,气液剪切引起的Kelvin-Helmholtz(K-H)不稳定和声振引起的参数不稳定之间存在竞争关系.奥内佐格数的增大、弹性数的减小和时间常数比的增大会抑制液膜的失稳.韦伯数的增大对K-H不稳定有促进作用,但是对参数不稳定具有双重作用,一方面韦伯数的增大减弱了表面张力,促进液膜失稳,另一方面韦伯数的增大使得参数不稳定区域的波数增大,增强粘性对不稳定的抑制作用,抑制液膜失稳.邦德数的增大促进了参数不稳定,抑制了K-H不稳定.声振频率的增大使得K-H不稳定增强,参数不稳定减弱.
Abstract
In view of the possible acoustic oscillations in liquid rocket engines,the linear instability of the planar liquid film in the transverse acoustic field is analyzed theoretically.The momentum equation and boundary conditions of liquid film are described by the viscous potential flow theory.Based on Floquet theory,dispersion equation considering the coupling effect between the sinuous and varicose modes is obtained.The results show that there is a competitive relationship between the Kelvin-Helmholtz(K-H)instability caused by gas-liquid shear and the parameter instability caused by acoustic oscillaitons.The increase of Ohnesorge number,the decrease of elastic number and the increase of time constant ratio inhibits the instability of the liquid film.On one hand,the increase of Weber number weakens the surface tension and promotes the instability of liquid film.On the other hand,the increase of Weber number increases the wavenumber in the parameter instability region,which enhances the inhibition effect of viscosity on instability and inhibits the instability of liquid film.The increase of Bond number promotes parameter instability and inhibits K-H instability.With the increase of acoustic frequency,K-H instability is enhanced and parameter instability is weakened.
关键词
声学振荡/Kelvin-Helmholtz不稳定/参数不稳定/线性不稳定性/粘弹性Key words
Acoustic oscillations/Kelvin-Helmholtz instability/Parametric instability/Linear instability/Viscoelastic fluids引用本文复制引用
基金项目
国家自然科学基金青年科学基金项目(12302325)
河北省自然科学基金青年项目(A2023105004)
北京市科协青年人才托举工程()
出版年
2024
NETL
NSTL
万方数据