Pressure changes associated with the ascent and bursting of gas slugs in liquid-filled vertical and inclined conduits
Pressure changes associated with the ascent and bursting of gas slugs in liquid-filled vertical and inclined conduits
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DOI：
10.1016/s0377-0273(03)00232-4
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发表时间：
2004-01-15
影响因子：
2.9
通讯作者：
Gilbert, JS
中科院分区：
文献类型：
--
作者：
James, MR;Lane, SJ;Gilbert, JS
在玄武岩火山，长周期和超长周期地震活动和声学信号的来源经常被描述为流体动力学过程，特别是岩浆柱内气团的形成和上升及其在地表的破裂。为了研究与这些过程相关的压力变化，在垂直管道和倾斜管道中进行了两相流动实验，其中包括单个气塞和连续供应的气相。单个气段塞的上升伴随着液体绕段塞流动而产生的强烈的动态压力变化。在粘度控制系统中，这些动态瞬变在上升段塞下方产生亚静态压力，而在惯性主导系统中，当段塞到达表面且运动停止时，这些动态瞬变会产生超静态压力。管道倾斜促进了从泡状流到段塞流的转变，有利于段塞尺寸和速度的增加，但在连续供应的两相流中，段塞的出现频率有所下降。实验压力数据支持了以前的理论分析，即当弹状物接近表面并爆炸时，上升弹状物中的振荡源。在气塞释放过程中及其尾流区也观察到了压力振荡。(C)2003爱思唯尔B.V.保留所有权利。
At basaltic volcanoes, the sources of long-period and very-long-period seismicity and acoustic signals are frequently described in terms of fluid dynamic processes, in particular the formation and ascent of gas slugs within the magma column and their bursting at the surface. To investigate pressure changes associated with these processes, two-phase flow experiments have been carried out in vertical and inclined pipes with both single gas slugs and a continuously supplied gas phase. The ascent of individual gas slugs is accompanied by strong dynamic pressure variations resulting from the flow of liquid around the slug. These dynamic transients generate sub-static pressures below the ascending slug in viscosity-controlled systems, and produce super-static pressures when the slug reaches the surface and motion ceases in inertia-dominated systems. Conduit inclination promotes a change of regime from bubbly to slug flow and favours an increase in size and velocity of the slugs at the expense of their frequency of occurrence during continuously supplied two-phase flow. The experimental pressure data support previous theoretical analyses of oscillatory sources in ascending slugs as the slugs approach the surface and burst. Pressure oscillations are also observed during the release of gas slugs and in their wake region. (C) 2003 Elsevier B.V. All rights reserved.