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大尺寸液桥热毛细对流失稳性地面实验研究

GROUND EXPERIMENTS ON THE INSTABILITY OF THERMOCAPILLARY CONVECTION IN LARGE SCALE LIQUID BRIDGE

  • 摘要: 开展大尺寸液桥浮力-热毛细对流地面实验, 探究流场转捩的临界条件及临界状态附近的流动情况. 通过粒子图像测速方法(PIV) 获得流体速度场, 研究液桥内部定常和转捩后的流场结构以及流体运动规律;并用红外热像仪测量液桥自由面温度分布, 研究流体流动的时空演化和温度振荡. 实验发现大尺寸半浮区液桥浮力-热毛细对流临界值与几何参数有关, 在大普朗特(Prandtl) 数情况下, 流场存在由稳定态向不稳定态再到混沌的转捩过程, 在临界马兰哥尼(Marangoni) 数附近, 流场内会出现行波现象, 流动模式也会随高径比的变化而发生变化;当继续增大马兰哥尼数, 流动会进入混沌状态.

     

    Abstract: In this paper, PIV and thermal infrared camera are used to observe the flow field structure and temperature distribution respectively. In large Prandtl number condition, the critical temperature difference or the corresponding Marangoni number will tend to decrease with the increase of volume ratio and the ratio of height to diameter, besides, the fluid field can flow from stable state via unstable state to oscillation and will change along with the change of high aspect ratio. Traveling wave will appear when the Marangoni number exceeds the critical value, and chaos will follow with higher Marangoni number.

     

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