水平管段塞流相界面参数的超声相控阵测量及分析

Measurement and Analysis of Phase Interface Parameters of Horizontal Pipe Section Plug Flow Based on Ultrasonic Phased Array Technology

段塞流是两相流的一种典型流型,其流动的间歇性、不稳定性在传输过程中会带来许多问题。本文采用超声相控阵技术对段塞流相界面进行了测量和分析。通过设计聚焦法则,确定扫描声束、偏转角度和实验参数,在气液两相流装置上开展了18种流动条件下的实验测量。结合扇扫界面的数据分析,利用四阶多项式方程拟合方法获取了气液相界面曲线,提取了两相界面中心点处液位高度和截面含气率两个特征值。结果表明,当气相表观流速一定时,随着液相表观流速的增加,液位高度增加。当液相表观流速一定时,随着气相表观流速的增加,液位高度下降。通过比较数据得出气相表观流速的变化对段塞流液位高度影响更加显著。此外,气相和液相表观流速滑差的增大会导致液位高度升高,截面含气率降低,气液表观流速之差较小时,气液界面波动较大,液位高度和截面含气率变化明显。该测量方法为段塞流流动参数测量奠定了基础。

Plug flow is a type of two-phase flow,which is intermittent and unstable,and lacks real-time accurate detection means.Ultrasonic phased array is adopted to detect the phase interface of gas-liquid two-phase flow and corresponding analysis is performed.The focusing law is designed,then the scanning acoustic beam,deflection angle and experimental parameters are determined.Experimental measurements are conducted under 18 flow conditions,and the acquired data are analyzed.4 th-order polynomial equation fitting method is ultilized to obtain the gas-liquid interface and two feature values,i.e.,the liquid level height at the center of the gas-liquid interface and the cross-section gas content rate.The results show that when the gas superficial velocity is fixed,the liquid level height increases with the increase of the liquid superficial velocity.When the liquid superficial velocity is fixed,the liquid level height decreases with the increase of the gas superficial velocity.It is deduced that the change in the gas superfacial velocity has more significant influence on the liquid level height of the plug flow after comparing the data.In addition,the increase of the superfacial flow velocity slip between the gas and liquid phases leads to the increase of the liquid level height and the decrease of the cross-section gas content rate.When the difference of the superfacial flow velocity between the gas and liquid phases is small,the gas-liquid interface fluctuates more apparently and the liquid level height and cross-section gas content rate change significantly.The method lays the foundation for the measurement of gas-liquid two-phase flow parameters.