水平管内气液两相螺旋流实验研究

Experimental Research on Gas-Liquid Two-Phase Spiral Flow in a Horizontal Pipe

为研究水平管内气液两相螺旋流的流动特性,开展了以空气和水为实验介质,含气率为10%～90%,气相折算速度为0.01～3.4m/s,液相折算速度为0.05～2.7m/s的气液两相螺旋流实验。利用高速摄影机记录并参考借鉴相关研究结果分析和划分了不同工况下的流型;给出了水平管内气液两相螺旋流的流型图;研究了不同流速、不同起旋参数对流动特性(压降、流型衰减、螺距、螺旋直径以及流型转换边界等)的影响。实验结论如下:将水平管内气液两相螺旋流的流型划分为螺旋波状分层流、螺旋泡状流、螺旋团状流、螺旋线状流、螺旋轴状流、螺旋弥散流6种;将绘制的流型图与经典Mandhane流型图进行对比,出现了线状流、弥散流和轴状流3种新的流型;泡状流的分布基本不变,层状流的分布发生变化,当气相流速在2m/s以内时是线状流和轴状流,而不是层状流;随着液相流速的提高,管内两相流动的损失逐渐变大,流型的衰减程度变弱,螺旋扭矩逐渐变大,螺旋直径逐渐变小。另外,随着叶轮角度的增大或者随着叶片面积的减小,流型转换边界均向进气量增大的方向推移。而当进气量一定时,随着叶轮角度的增大或者随着叶片面积的减小,同样流型转换边界趋于进水量增大的方向。最后,随着起旋角度的增大或者随着叶片面积的减小,压降均有逐渐变大的趋势。

In order to study the flow characteristics of gas-liquid two-phase spiral flow in a horizontal pipe, experimental investigation on gas-liquid two-phase spiral flow with 10% - 90% gas volume fraction, 0.01-3.4 m/s gas superficial velocity and 0. 05-2.7 m/s liquid superficial velocity was conducted. The flow patterns under different conditions were analyzed and classified based on high- speed camera records and reference of related investigation results; flow pattern map of gas-liquid two- phase spiral flow in a horizontal pipe was presented; the effect of different velocities and different original spin parameters on flow characteristics, such as pressure drop, flow pattern attenuation, spiral distance and spiral diameter, were investigated. Experimental results are as follows： The flow patterns appeared in the horizontal pipe may be divided into spiral wave stratified flow （SWS）, spiral bubbly flow （SB）, spiral slug flow （SS）, spiral linear flow （SL）, spiral axial flow （SA） and spiral dispersed flow （SD）. Among these patterns, the linear flow, axial flow and dispersed flow are three new kinds of flow patterns, which is obtained by comparison between the flow pattern map obtained in experiment and classical Mandhane flow pattern map. The distribution of bubbly flow is basically constant, but the distribution of stratified flow changes. When the gas flow rate is less than 2 m/s, linear flow and dispersed flow appear rather than laminar flow. Along with the increase of liquid velocity, the two-phase flow loss gradually increases, the attenuation of flow type becomes weak, spiral distance gradually increases, spiral diameter gradually decreases. In addition, with the increase of vane angle or with the decrease of vane area, the flow pattern transition boundary moves towards the direction of gas intake rate increasing. When gas intake quantity is constant, the flow pattern transition boundary of the same flow pattern moves towards the direction of liquid feed rate increasing along with the increase of vane angle or with the decrease of vane area. At last, the pressure drop gradually increases with the increase of original spin angle or with the decrease of vane area.