振荡作用下气液两相流的流动特性

Flow Characteristics of Gas-liquid Two-Phase Flow under Oscillation

为研究高强化活塞冷却油腔内气液两相流的振荡流动结构对其强化传热效果的影响,对矩形空腔内气液两相流的振荡流动过程进行了实验研究。结果表明:气液两相流在起振阶段和充分振荡阶段的振荡流动规律有着明显的区别,起振阶段两相流以"爬壁"运动为主,而充分振荡阶段两相流则以"绕壁"运动为主;振荡频率主要影响两相流中气泡的状态和湍流强度,而填充率则主要影响两相流的流动形态和运动规律,在起振阶段振荡频率和填充率对起振阶段时长和最大气泡尺度的变化都有显著影响,而在充分振荡阶段,振荡频率对于气泡尺度的影响要明显高于填充率。

In order to determine the influence of the oscillating flow structure of gas-liquid two-phase flow on its heat transfer enhancement,the experimental study of oscillating flow process of gas-liquid two-phase flow in a rectangular cavity was performed.The main results show that the oscillatory flow law of gas-liquid two-phase flow in primary oscillation stage differs much from that in full oscillation stage.During the primary oscillation stage the two-phase flow is dominated by the "climbing the wall" motion,however in the full oscillation stage,the two-phase flow is dominated by the "around the wall" motion.The state of the bubbles and the turbulence intensity in two-phase flow are mainly affected by oscillation frequency,and the flow pattern and the movement law of two-phase flow are mainly affected by filling rate.In the primary oscillation stage the oscillation frequency and filling rate both have significant influences on the duration of primary oscillation stage and the maximum bubble size,while in the full oscillation stage,the effect of oscillation frequency on the bubble size is clearly much higher than that of filling rate.