气液两相流压力波色散特性实验研究

设计了可调频式压力扰动源的气液两相流压力波实验装置,实验研究了垂直上升管内气液两相流泡状流、弹状流压力波的色散规律。实验结果表明,对泡状流,在实验范围内,压力波的传播速度及其衰减跟扰动频率有关,随着扰动频率的增加,波速及其衰减都增加;工质的流速对压力波的色散特性没有影响。结合数值模拟结果,验证了泡状流压力波色散特性的临界频率现象,即高于临界频率,压力波色散特性消失,本文分析了相应的物理机制。对弹状流,压力波同样具有典型的色散特性,已有研究结果还不能预测其色散规律。

MEASUREMENTS ON DISPERSION OF PRESSURE WAVE IN GAS-LIQUID TWO-PHASE FLOW

An experimental setup for gas-liquid two-phase flow has been designed, which can adjust the disturbed frequency of the pressure force acting on the piping flow without mass transfer. Experiments on the dispersion characteristics have been performed in vertical upward gas-liquid bubble flow and slug flow through a transparent pipe system under atmospheric pressure. Both pressure wave speed and attenuation were measured under different disturbed frequency with pressure transducers mounted flush to the pipe wall. In the bubbly flow, the results show that both the pressure wave speed and attenuation have close relation with the disturbed frequency. Both the wave speed and the attenuation increase with the disturbed frequency. However, the flow velocity of the two-phase fluid has no effect on the dispersion of pressure wave. Based on the experiment and the numerical simulation in reference 1], a new phenomenon is validated that the dispersion of pressure wave will disappear under the perturbation frequency greater than a critical frequency. And the physical mechanism of this new phenomenon is analyzed in the study. The pressure wave in the slug flow has also the feature of dispersion, but there are still no correlations to predict it.