摘要
针对现代城市深层隧道雨水排水系统中,竖井的高落差和大泄量等特点,该文提出了一种大转角阶梯泄水道竖井结构型式。采用物理模型试验,详细研究了其主要水力特性,包括:流态、时均动水压力、消能和掺气特性等。结果表明:对于一定的阶梯高度,大旋转角阶梯面的设置,可以形成跌落和水跃的流态,其联合作用产生高效的消能效果。沿流动方向,沿程时均动水压力较低;在径向上,由于离心力作用,至壁面压力逐步上升有利于避免空化的发生。跌落和水跃两种流态的组合作用有效地减小流动的总能量,降低流动的速度,同时,泄水道上流动的良好掺气,两者最终可以有效地减免空化空蚀的风险。
To meet the need of constructions of the urban deep tunnel drainage system with high head and large discharge, a kind of stepped spillway dropshafts with large angle is developed. The hydraulic characteristics are experimentally investigated, including flow regime, time-average pressure, energy dissipation and air entrainment. The results show that the combinations of nappe flow and hydraulic jump flow regimes are formed thanks to the large angle for some step height, and high energy dissipation is produced. In the flow direction, the time-average pressure is low, while the pressure along the radial direction increases due to the effect of the flow centrifugal force, supporting the decrease of cavitation risk. On the basis of the energy dissipations of the nappe flow and hydraulic jump, the flow speed decreases, and the air is entrained into the flow, and then the cavitation could be effectively controlled.
作者
吴建华
杨涛
沈洁艺
任炜辰
马飞
WU Jian-hua;YANG Tao;SHENG Jie-yi;REN Wei-chen;MA Fei(College of Water Conservancy and Hydropower Engineering, HoHai University, Nanjing 210098, China)
出处
《水动力学研究与进展（A辑）》
CSCD
北大核心
2018年第2期176-180,共5页
Chinese Journal of Hydrodynamics
基金
国家自然科学基金项目(51779081)~~
关键词
大旋转角
阶梯泄水道
竖井
水力特性
large angle
stepped spillway
dropshaft
hydraulic
characteristics
