低含液率气液两相钝体绕流实验与机理  

Experimental and Mechanistic Study on Vortex Flow Around a Bluff Body in Gas-Liquid Flow with Low Liquid Fraction

作　　者：孙宏军[1,2] 汪波[1,2] 李金霞[1,2] 丁红兵[1,2] 

机构地区：[1]天津大学电气与自动化工程学院,天津300072 [2]天津市过程检测与控制重点实验室,天津300072

出　　处：《天津大学学报（自然科学与工程技术版）》2016年第5期491-497,共7页Journal of Tianjin University：Science and Technology

基　　金：国家自然科学基金青年基金资助项目(50906061)

摘　　要：气液两相钝体绕流现象广泛存在于生产实践和社会生活中,其中气相中含少量液体是常见的两相流现象.通过实验,研究了常压下50,mm口径水平圆管中低含液率气液两相钝体绕流的涡街现象,就含液率对涡街信号的频率与幅值的影响进行比较分析,应用消除趋势波动法(DFA)对涡街信号进行处理,得到液相体积含率0.1%,左右是本实验条件下能产生稳定涡街的分界点.对实验流型——环状流进行了动力学分析,得到气、液相惯性力之比和液相韦伯数随含液率的变化规律,并从液相的分布与运动及气相夹带液滴对漩涡能量影响两方面,分析了涡街失稳的机理.最后利用拟合的两相斯特劳哈尔数和含液率之间的线性关系,使涡街在湿气及低含液率下的测量误差从6.37%,减小到2.03%,,对实际工程测量有一定的指导意义.The gas-liquid two-phase flow around a bluff body is widely encountered in the production practices and social lives.In this study,the vortex flow around a bluff body in 50,mm-caliber horizontal gas-liquid two-phase flow with low liquid fractions at normal pressure was investigated by experiments.The effects of liquid fractions on the frequency and amplitude of vortex signal were discussed,and then,vortex signals were processed by detrended fluctuation analysis（DFA）.A characteristic liquid volume fraction around 0.1%, for the stability of vortex street was attained.The relationship of liquid fractions with gas-liquid phase inertia forces and the liquid Weber number were discussed respectively by the dynamics analysis for annular flow.The law of vortex street instability was analyzed.It was found that the energy of vortex street would be dissipated by liquid phase and entrained droplets.The error of gasliquid two phase flow with low liquid fractions and moisture measure decreased from 6.37%, to 2.03%, by setting up the linear relationship of two-phase Strouhal number and liquid fractions,which is instructional in actual engineering.

关 键 词：气液两相流 钝体绕流 消除趋势波动法 动力学理论 涡街失稳 

分 类 号：O357.1[理学—流体力学]