2020/10/10 by Peng Xu, Xu, Peng, Shuhong Liu +5
Engineering · Materials Science · #Cavitation Phenomena in Pumps #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Ultrasound and Cavitation Phenomena #Water Systems and Optimization
paper · pdf · doi:10.48550/arxiv.2010.04911
openalex publication_date 2020/10/10 · openalex created_date 2020/10/15 · openalex updated_date 2026/07/28
Extreme cavitation scenarios such as water column separations in hydraulic systems during transient processes caused by large cavitation bubbles can lead to catastrophic destruction. In the present paper, we study the onset criteria and dynamics of large cavitation bubbles in a tube. A new cavitation number Ca2 = l^*-1 Ca0 is proposed to describe the maximum length Lmax of the cavitation bubble, where l^* is a non-dimensional length of the water column indicating its slenderness, and Ca0 is the classic cavitation number. Combined with the onset criteria for acceleration-induced cavitation (Ca1<1, Pan et al. (2017)), we show that the occurrence of large cylindrical cavitation bubbles requires both Ca2<1 and Ca1<1 simultaneously. We also establish a Rayleigh-type model for the dynamics of large cavitation bubbles in a tube. The bubbles collapse at a finite end speed, and the time from the maximum bubble size to collapse is Tc=√(2)√lLmax√\fracρp_∞, where l is the length of the water column, Lmax is the maximum bubble length, ρ is the liquid density, and p∞ is the reference pressure in the far field. The analytical results are validated against systematic experiments using a modified 'tube-arrest' apparatus, which can decouple acceleration and velocity. The results in the current work can guide design and operation of hydraulic systems encountering transient processes.