Effects of liquid temperature on cryogenic cavitation bubble dynamics near a rigid plate

To reveal the specific effects of liquid temperature on cryogenic cavitation bubble near a rigid plate, cavitation bubble dynamics in liquid nitrogen at 68–75.5 K are experimentally investigated in this study. Four typical jet patterns of liquid nitrogen bubble, namely the first-collapse jet, rebound jet, second-collapse jet, and no visible jet are observed. These patterns emerge sequentially as the dimensionless standoff distance γ increases. An increase in liquid temperature reduces jet velocity and decreases the critical γ value for the transition between different jet patterns. The impacts of temperature on overall migration of liquid nitrogen bubble depends on γ. For the smaller γ, the liquid nitrogen bubbles reach the plate at all tested temperatures. For the larger γ, liquid nitrogen bubbles at relatively low temperatures break up before reaching the wall. In contrast, higher liquid temperatures reduce the subcooling degree, making thermal effects and phase-change-related processes increasingly important in regulating bubble evolution. This significantly prolongs the evolution time, enabling the bubble to arrive at the plate before breaking. Furthermore, the absolute values of Bjerknes force and Kelvin impulse decrease with rising liquid temperature, causing the first bubble collapse position to move away from the rigid plate.