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.

微米级间隙容易产生气穴现象，影响流体机械的效率和可靠性。由于约束效应和高速剪切作用，空化气泡的演化过程在约束间隙中呈现出新的特征。本文根据微米间隙的结构特点研制了一种可视化实验装置。在高速可视化实验中捕获了 R134a 在发散和收敛流路中的空化特性和气泡动力学。对于单个空化气泡，研究了不同过冷度和间隙高度下的生长、变形和破碎过程。在实验过程中捕获了单气泡的形状和生长过程。拟合曲线是基于微米间隙中的流动和单气泡形态获得的。单气泡和气泡簇的出现概率随过冷度、间隙高度和压力差而变化。