垂直气液两相管流中的空隙率波测量

在直径为112.5mm, 长度12m的垂直管中，利用阻抗式空隙率计对垂直气液两相管流空隙率波进行了测量。结果表明连续相表观流速和管径对流态的演化和空隙率波的传播特性有较大的影响。连续相表观流速大，泡状流失稳的临界含气率低；管径大，空隙率波的传播速度高。分析结果表明流动湍流度对流态的演化起非常重要的作用。对空隙率波的分析表明不同流态的空隙率波的PDF和频谱曲线具有不同的特征；含气量越高，空隙率波的频率越趋于单一。

Measurement of Void Fraction Wave in Vertical Gas-liquid Flow

Gas-liquid two phase flow experiments were conducted in a vertical pipe whose diameter is 112.5mm, and length is 12m. Void fraction waves were measured by impedance void fraction meters and analyzed. The results show that the liquid superficial velocity and the pipe diameter are two main factors to affect the evolution of the flow regime and the characteristics of void fraction wave. The critical void fraction of bubbly flow losing its stability becomes lower with the liquid superficial velocity goes high. The propagating velocity value of void fraction wave is higher in big diameter pipe than that of small diameter pipe. Analyzing results show that the turbulivity plays an important role in the process of flow regime evolution. The analysis on void fraction waves shows that the curves of PDF and amplitude spectrum in different regimes are different, and the frequencies of void fraction waves become single with increasing of void fraction.