水电能源科学

为研究山区高落差起伏地形下重力流关阀水锤，以高落差起伏地形下重力流为基础，通过在不同关阀时间下计算某工程不同阀门流量特性曲线、不同检修阀位置以及超压泄压阀水锤压力，得到高落差起伏地形下关阀水锤规律。结果表明，阀门的流量特性曲线是影响水锤的内因，选择慢关型阀较快关型阀能有效减小水锤压力；局部制高点是末端关阀产生负压的关键，而起伏地形下管中关阀还需考虑下游侧局部凸起点产生负压影响；长平直至高点(如长距离隧洞)仅靠放水锤空气阀无法消除负压，而在下游侧增设超压泄压阀能有效消除；关阀时间变化对不同位置事故检修阀关阀水锤压力值不同，越靠上游位置阀门受水锤波的叠加影响水锤压力值变化幅度越快，增设超压泄压阀后不同位置阀门压力值变化基本一致。

In order to study on water hammer during valve closure in gravity driven flow systems across mountainous terrain with significant elevation changes, this study established a model based on such topographical conditions. By calculating the flow characteristic curves of different valves in a certain project, the positions of different maintenance valves, and the water hammer pressure of the overpressure relief valve at different valve closing times, the water hammer law of valve closing under high drop undulating terrain was obtained. The results show that the flow characteristic curve of the valve is an internal factor affecting water hammer. Choosing slow-closing valves can effectively reduce water hammer pressure. Local high points are critical for negative pressure generation during terminal valve closure. When closing valves in pipes under undulating terrain, the negative pressure impact caused by local protrusions on the downstream side also needs to be taken into consideration. In extended flat sections followed by high points(e.g., long distance tunnels), air valves alone cannot eliminate negative pressure. Installing pressure relief valves on the downstream proves effective for mitigation.The water hammer pressure value of the valve at different positions during accident maintenance varies due to the change in valve closing time. The upstream position of the valve is affected by the superposition of water hammer waves, and the change in water hammer pressure value is faster. After adding an overpressure relief valve, the pressure value changes of valves at different positions are basically the same.