Abstract:

A capacitance measurement system for vertical upward gas-liquid two-phase flow has been established to explore the feasibility for measuring fluid phase-concentration by using concave capacitance sensor and double helix capacitance sensor. The experimental results prove that the concave capacitance sensor has poor measurement resolution, but double helix capacitance sensor shows high resolution in phase-concentration measurement. The fluctuation signals of the two types of capacitance sensors are analyzed by means of time frequency analysis. The time frequency representation can effectively identify flow patterns and characterize their motion clearly. Finally, the drift model of gas-liquid two-phase flow is employed based on the measurement signals of double helix capacitance sensor. Moreover, the phase superficial velocities are estimated for slug and churn flow patterns, and good prediction results are achieved. The results show that the double helix capacitance sensor possesses a good application prospect for measuring the flow parameter in gas-liquid two-phase flows.

Key words: gas-liquid flow, phase-concentration, concave capacitance sensor, double helix capacitance sensor, measurement, model

摘要：

为了考察两种电容传感器(对壁式及双螺旋式)测量气液两相流相浓度的适应性,搭建了垂直上升气液两相流电容传感器测量系统。实验表明对壁式电容传感器测量分辨率较差,而双螺旋式电容传感器对相浓度具有较高的分辨能力。采用时频分析方法对电容传感器波动信号进行了分析,发现两种电容传感器的时频联合表达均能清晰地表征流型运动特征,并可对流型进行有效辨识。最后,基于双螺旋式电容传感器测量信号,建立了气液两相流漂移模型,取得了对段塞流和混状流分相表观流速较好的预测结果。研究表明,双螺旋式电容传感器在气液两相流流动参数测量上具有较好的应用前景。

关键词: 气液两相流, 相浓度, 对壁式电容传感器, 双螺旋式电容传感器, 测量, 模型