抄録
In this paper the dynamics of cavitation vapor bubble in cryogenic liquid nitrogen are investigated experimentally and analytically. The bubbles are produced by focusing a giant pulse of Q-switched ruby laser into the liquid nitrogen in a cryostat, and the dynamics of the laser-induced bubble are studied by means of high-speed photography by using an image converter camera with the framing rates of 105 frames/s. A numerical analysis is also performed on the behavior of a bubble in cryogenic liquid. The mathematical formulation takes account the effect of liquid inertia (incompressible liquid), non-equilibrium condensation of the vapor in the bubble, and the heat transfer at the bubble wall. The experimental data on the bubble motion in liquid nitrogen under the near-equilibrium initial conditions with an atmospheric pressure are compared to the numerical solutions. Among the results obtained, the bubble motion observed indicates more violent and decaying behavior than the estimated tendency. The heat and mass transfer effects including the evaporation and condensation phenomena have the strong influence on the vapor bubble motion in cryogenic liquid. Qualitatively the numerical analysis can simulate the experimental results.
