Experimental Investigation of the Instability of Cavitation in Veturi Tube under Different Cavitation Stage

doi:10.3901/JME.2018.02.209

Abstract

Abstract: A high-speed camera is used to observe the cavitation flow under different stages corresponding to the cavitation number of 0.76, 0.51 and 0.26. The shedding ways of cavity cloud under different conditions are compared. The area variations of cavity cloud are analysed by image processing tools. The relations between shedding laws of cavity cloud and change laws of pressure in different position are studied. The experimental results are conducted. Cavity cloud produced from internal face in throat of venture tube develops downstream, and periodically sheds in different ways under different cavitation stages. As cavitation number reduces orderly, the shedding ways of cavity cloud convert to unilateral shedding from bilateral shedding. Particularly, unilateral shedding mostly consist of nether shedding. When cavitation is very severe, multistage discontinuous cavity cloud appear in the diffuser. Additionally, the shedding of cavity cloud has a strong association with the pressure fluctuation in three different position in diffuser, but it has little association with the pressure fluctuation in throat. The dominant shedding frequency nearly corresponds to the dominant frequency of pressure fluctuation. And both of the dominant frequency orderly decrease as cavitation get violent, respectively corresponding to 275.9 Hz, 176.8 Hz, 12 Hz.

Key words: cavity cloud, high-speed camera technology, pressure fluctuation, shedding, Venturi tube

LONG Xinping, WANG Jiong, ZUO Dan, ZHANG Junqiang, JI Bin. Experimental Investigation of the Instability of Cavitation in Veturi Tube under Different Cavitation Stage[J]. Journal of Mechanical Engineering, 2018, 54(2): 209-215.

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