Smart Cities Research Institute, Zhengzhou University, Zhengzhou 450001, China; State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing 210029, China E-mail:
State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing 210029, China E-mail:
Water Sci Technol. 2017 Apr;2017(1):66-76. doi: 10.2166/wst.2018.085.
Geysers of air-water mixtures in urban drainage systems is receiving considerable attention due to public safety concerns. However, the geyser formation process and its relation with air release from pressurized pipes are still relatively little known. A large-scale physical model, that consisted of a main tunnel with a diameter of 270 mm and a length of 25 m connecting two reservoirs and a vertical vent pipe, was established to investigate geyser evolution and pressure transients. Experimental results including dynamic pressure data and high speed videos were analysed in order to characterize geysering flow through the vent pipe. Pressure transients were observed during geysering events. Their amplitudes were found to be about three times the driving pressure head and their periods were close to the classic surge tank predictions. The influence of flow rate and vent pipe size were examined: geyser heights and pressure peaks decreased for small flow rate and large diameter vent pipe. It is suggested that geyser heights are related with the pressure head and the density of the air-water mixture.
由于公共安全问题，城市排水系统中的汽水混合物喷泉受到了相当大的关注。然而，喷泉的形成过程及其与加压管道中空气释放的关系仍知之甚少。建立了一个大型物理模型，由一个直径为 270 毫米、长 25 米的主隧道连接两个水库和一个垂直通风管组成，以研究喷泉的演变和压力瞬变。分析了包括动压数据和高速视频在内的实验结果，以描述通过通风管的喷泉流动。在喷泉事件中观察到压力瞬变。发现它们的幅度约为驱动压力头的三倍，其周期接近经典的调压室预测。还研究了流量和通风管尺寸的影响：小流量和大直径通风管会降低喷泉高度和压力峰值。建议喷泉高度与压力头和空气-水混合物的密度有关。
