垂直上升管内泡状流压力波传播

研究了垂直上升管内气液两相泡状流压力波的传播速度和衰减规律，为了提高压力波测量精度．实验中设计了不影响两相流动结构的调频式压力扰动装置．实验结果表明，随着含气率的增加，泡状流中压力波波速开始陡降，当含气率大于0．05以后波速缓慢下降；衰减系数随含气率的增加连续增加：工质的流速对压力波的传播没有影响；压力波的传播速度及其衰减与扰动频率有关．随着扰动频率的增加，波速及其衰减都增加本文实验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．压力波的色散特性消失．在本试验条件和参数范围内．临界扰动角频率为300Hz．

Propagation of Pressure Wave for Bubbly Flow in Vertical Upward Tube

Experimental investigation was carded out to study the pressure wave speed and its attenuation for gas-liquid bubbly flow in vertical upward tube. In order to improve the measurement accuracy of the pressure wave, a setup was designed to adjust the frequency of the pressure force acting on the piping flow without changing the two-phase flow regime. The propagation of the two-phase flow pressure wave was measured with several pressure transmitters mounted flush to the pipe wall along the flow direction. The results showed that the wave speed in bubbly flow decreased fleetly with the void fraction and decreased slowly when void fraction was more than 0.05. The attenuation had increased continuously with the void fraction.The flow velocity of the fluid mixture had not any effect on the propagation of pressure wave. Both the wave speed and attenuation coefficient had close relationship with the perturbation frequency, which increased with the disturbed frequency under low value range. A new phenomenon about critical disturbed frequency of the pressure wave dispersion in bubbly flow was validated in the present experimental investigation, which the dispersion of pressure wave would disappear under the perturbation frequency greater than a critical value.The critical frequency was about 300Hz in the experimental test.