Interfacial Waves in Accelerated Gas-Liquid Two-Phase Flows

通过空气-水系统实验，模拟了蒸发器管内加速气液两相流动。用电导法测量了水平矩形流道中的界面波特性。从液膜厚度变化的功率谱密度和互相关函数出发，分析了扰动波产生、发展和衰减的机理。(1)通过对加速流道的目测，绘制了流型图。在较低气体流量下，通道高度对流型转变有影响。与以单位流道宽度的液体质量流量为参数的计算结果相比，表观气液速度对流型转变的预测效果较好。(2)阐明了水平矩形流道内加速两相流的界面波特性。在加速度作用下，二维波发生变形，出现扰动波。分析了各波的幅值与频率之间的相互关系。(3)利用空气-水系统进行模拟实验，可以有效地考察蒸发管内的界面波特性。

An accelerated gas-liquid two-phase flow in an evaporator tube was simulated by an air-water system experiment. Characteristics of interfacial waves in a horizontal rectangular channel were measured by the electrical conductance method. Mechanisms of generation, growth and decay of the disturbance wave were analized considering the power spectrum density and the cross correlation function of variations of the liquid film thickness.(1) Flow pattern maps were constructed from the visual observation in the accelerated channels. At lower gas flow rate, the channel height affected the flow pattern transition. Flow pattern transitions were predicted fairly well by using the superficial gas and liquid velocities, compared to the results using liquid mass flow rate per unit channel width as a parameter.(2) Characteristics of interfacial waves of accelerated two-phase flow in a horizontal rectangular channel were clarified. Under acceleration two-dimensional waves were deformed and the disturbance waves appeared. Mutual relationships between amplitudes and frequenices of those waves were analized.(3) The simulation experiment by an air-water system was considered to be valid for the examination of interfacial wave characteristics in the evaporator tube.