EXPERIMENTAL AND APPLICATIVE STUDIES ON CAVITATION BUBBLE DYNAMICS IN CRYOGENIC LIQUID HYDROGEN

对液氢等低温液体中汽泡空化动力学进行了实验和分析研究。随着航空航天、液化天然气等低温工程技术的迅速发展，对低温流体中的空化现象进行研究变得十分必要。激光诱导空泡的研究已经引起了许多学者的关注。通过应用激光诱导气泡生成，气泡本身在时间和空间上都被精确控制。在这项研究中，气泡是通过将Q开关红宝石激光器的巨大脉冲聚焦到低温恒温器中的低温液体（液氮，氢和Ar）中来产生的。利用Imacon-790高速摄影机研究了低温液体中激光诱导气泡的动力学过程。采用PCB压电陶瓷测量冲击压力 ...更多信息 tric传感器对低温液体中气泡的物理行为进行了数值分析。该数学公式考虑了液体惯性、蒸汽的非平衡冷凝和气泡壁处的传热的影响。对低温液体中单个气泡的运动进行了数值模拟，并与实验结果进行了比较。主要结果如下：（1）要在低温恒温器中产生高度球形的气泡，必须消除聚焦透镜的像差。采用光阑装置，观察了低温液体中气泡的行为。(2)数值模拟了液氮、氢气和氩气中的气泡动力学。在包括气泡壁处的热传递的情况下，气泡指示剧烈的行为。汽泡运动受蒸发和冷凝系数（非平衡参数）的影响很大。数值计算结果与实验结果进行了比较。少

The experimental and analytical investigations have been conducted on the dynamics of cavitation vapor bubbles in cryogenic liquids including liquid hydrogen. With the rapid progress of cryogenic engineerings such as aerospace technology and LNG plants, it becomes necessary to study cavitation phenomena in cryogenic fluids. Laser-induced cavitation bubbles have been investigated by many researchers. By applying the laser-induced bubble generation, the bubble itself is precisely controlled both temporally and spatially. This technique does not cause any large disturbances in the surrounding liquids.In this research, bubbles are produced by focusing a giant pulse of a Q-switched ruby laser into cryogenic liquid (liquid nitrogen, hydrogen, and Ar) in a cryostat. The dynamics of the laser-induced bubbles in cryogenic liquids were studied by means of high-speed photography using a Imacon-790 camera with framing rates of up to 100000frames/s. The impact pressure was measured by PCB piezoelec … More tric transducer. A numerical analysis was also developed for the physical behavior of the bubble in cryogenic liquids. The mathematical formulation takes into account the effects of liquid inertia, the none-equilibrium condensation of vapor, and the heat transfer at the bubble wall. The numerical solutions were compared to the experimental results on single bubble motion in cryogenic liquid. The main results are summarized as follows: (1) The aberration of the focusing lens must be removed, in order to produce a highly spherical bubble in the cryostat. An iris has been used, and the bubble behaviors in cryogenic liquids were observed. (2) Bubble dynamics in liquid nitrogen, hydrogen, and argon were simulated numerically. In the case of including heat transfer at the bubble wall, the bubble indicates a violent behavior. The bubble motion received a very strong influence by the coefficient for evaporation and condensation (non-equilibrium parameters). The numerical results were compared with experimental results. Less