Analysis of safety monitoring indicators of dragon-head spillway tunnel
ZHANG Chunjin1, SUN Xihuan2*, LI Yongye2
1. Key Laboratory of Lower Yellow River Channel and Estuary Regulation, Yellow River Institute of Hydraulic Research, Zhengzhou Henan 450003, China; 2. School of Hydro Science & Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024, China
Abstract：Based on the 1∶40 normal hydraulic model experiment, the RNG k-ε two-equation turbulence model is used to analyze the hydraulic characteristics of the flow field in the connection sections of the Xiaolangdi Hydropower Station 2# dragon-head spillway tunnel under the two characteristic flood level conditions of design and verification.The hydraulic characteristics of the spillway tunnel, such as the discharge capacity, the velocity distribution, the pressure distribution and the cavitation number were analyzed. At the same time, the safety monitoring indicators of the dragon-head spillway tunnel were proposed from the perspectives of the cavitation number, the cross-section velocity, the piezometric head and the remaining space of roof, and the safety monitoring and early warning levels of the dragon-head spillway tunnel were constructed. Research conclusions: the simulated results of the flow coefficient, the cross-sectional velocity and the piezometric head were in good agreement with the experimental results, which indicated that the numerical simulation can better calculate the hydraulic characteristics of the flow field in the connection section of the dragon-head spillway tunnel. The risk degree of the dragon-head spillway tunnel can be divided into four levels of early warning status: safety, low-alarm, medium-alarm and high-alarm. The safety monitoring indicators that affect the safe operation of the dragon-head spillway tunnel in descending order of the weigh were the cavitation number, the piezometric head, the remaining space of roof and the cross-section velocity. This research will provide theoretical guidance and technical support for the optimization design and safe construction of the dragon-head spillway tunnel.
