• CN:11-2187/TH
  • ISSN:0577-6686

机械工程学报 ›› 2019, Vol. 55 ›› Issue (18): 173-179.doi: 10.3901/JME.2019.18.173

• 交叉与前沿 • 上一篇    

文丘里管空化流动的试验研究及动力学模态分解

韩亚东, 谭磊   

  1. 清华大学水沙科学与水利水电工程国家重点实验室 北京 100084
  • 收稿日期:2018-09-14 修回日期:2019-03-28 发布日期:2020-01-07
  • 通讯作者: 谭磊(通信作者),男,1984年出生,博士,特别研究员,博士研究生导师。主要从事流体机械及工程研究。E-mail:tanlei@mail.tsinghua.edu.cn
  • 作者简介:韩亚东,男,1995年出生,硕士研究生。主要从事流体机械及工程研究。E-mail:hf20120401@163.com
  • 基金资助:
    国家自然科学基金(51809148)、北京市自然科学基金(3192015)、水沙科学与水利水电工程国家重点实验室自主科研(2018-KY-02)和水沙科学与水利水电工程国家重点实验室开放基金(sklhse-2018-E-01)资助项目。

Experiment and Dynamic Mode Decomposition of Cavitating Flow in Venturi

HAN Yadong, TAN Lei   

  1. State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084
  • Received:2018-09-14 Revised:2019-03-28 Published:2020-01-07

摘要: 已有空化研究侧重于空泡形态、漩涡脱落和压力脉动等方面,尚未开展空化流场动力学模态的研究。通过试验测量、数值模拟和动力学模态相结合,对文丘里管空化流动的流动结构及模态进行研究。试验测量获得文丘里管空化流动时空演变规律,得到空泡脱落周期为0.019 5 s。数值模拟采用质量输运空化模型,得到空泡脱落周期为0.02 s,与试验吻合较好,验证了数值模拟方法的准确性和可靠性。非定常流场表明,空泡与旋涡存在相互作用,反向射流引起了空泡脱落。应用动力学模态分解方法获得空化流场的动力学模态,结果表明四个主导模态频率与空化脱落频率存在倍数关系,频率较大的模态尺度较小。平均流场模态结果发现文丘里管喉部存在反向射流,其他三个模态揭示了空化发展和脱落的结构特征,并发现空化云向下游运动过程中对周围流体存在卷携作用。动力学模态分解能够准确捕捉空化流动中的主要动力学特征。

关键词: 文丘里管, 空化, 试验, 数值模拟, 动力学模态分解

Abstract: The previous studies mainly concentrate on the evolution of cavity shape, vortex shedding and pressure fluctuation, etc., while the study of dynamic modes of cavitation flow has not been developed. The flowing structures and dynamic modes of cavitation flow is investigated by means of experiment, numerical simulation and dynamic mode decomposition. The temporal and spatial evolution of cavitation flow in venturi are obtained by experiment, which shows the shedding period is 0.019 5 s. The mass transport cavitation model is used in numerical simulation, results show that the shedding period is 0.02 s, which is consistent with that of 0.019 5 s in the experiment result, and validates the accuracy and reliability of the numerical simulation. The results of unsteady flow field show that the cavity and vortices interact with each other, and cavity shedding is induced by the reentrant jet. The dynamic modes of cavitation flow are obtained by applying dynamic mode decomposition, results show that the frequencies of four dominant modes obtained are times of the shedding frequency. The higher frequency mode has a smaller scale. The mode which represents the time-averaged flow filed reveals the reentrant jet, and the other modes reveal the structure of cavitation development and shedding. Meanwhile, the roll-up process of entertainment fluid induced by the movement of shedding cavity is also revealed. The dynamic mode decomposition can accurately capture the flow mechanism and dominant dynamic behaviors of cavitation flow.

Key words: venturi, cavitation, experiment, numerical simulation, dynamic mode decomposition

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