Experimental study on vaporous cavitation of R134a in micron clearance

Abstract

Cavitation is likely to occur in micron clearance, which affects the efficiency and reliability of the fluid machinery. Due to the confinement effect and high-speed shearing, evolution process of cavitation bubbles takes on new characteristics in the confined clearance. In this paper, a visualized experimental apparatus was developed based on the structural characteristics of micron clearance. The cavitation characteristics and bubble dynamics of R134a in divergent and convergent flow path are captured in the high-speed visualization experiment. For the single cavitation bubble, the growth, deformation and fragmentation processes are investigated under different subcooling degrees and clearance heights. The shape and growth process of single-bubble is captured during experiment. The fitting curves are obtained based on the flow and the single-bubble morphology in the micron clearance. The occurrence probability of single-bubble and bubble cluster varies with subcooling degree, clearance height and pressure difference.