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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2022, Vol. 43 ›› Issue (3): 125212.doi: 10.7527/S1000-6893.2021.25212

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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)

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

CLC Number: