关键词: 停泵水锤, 二次保护措施, 被动型后保护, 主动型预防, 弥合水锤, 泵站

Abstract: In order to choose adequate secondary-protective measure for water hamper in case of pump failure, the solution of transient flow in pipe channel is determined by the application of characteristic equations on basis of the characteristics of pipeline system in pump station. Bentley Haestad Hammer software is employed to simulate the transient state process of the sub-project of Songji Changjiang River water lifting project in Chongqing, lifting water from Jinzishan high level pool to upstream reservoir, and the internal water pressure variation of the pipeline is calculated under 3 working conditions: pump-failure water hammer, passive post-protection and active prevention. The results show that the peak water pressures of 3 working conditions are 252.8 m, 191.8 m and 174.01 m, the upsurge ratios are 1.50, 1.44 and 1.05. While the pump shutdown time are 3.74s, 3.77s and 4.60s, and pump did not reverse under each working conditions. The transient water head shows an arch curve for passive post-protection, while for the active prevention the water head curve closes to the normal water head curve. The pressure fluctuation range of 3 working conditions are 71.4~254.8m, 70.7~181m and 46~174m at the outlet of the valve and the fluctuation for active prevention is the gentlest. The comparison of water hammer effects in 2 protection modes shows that the active prevention can reduce maximum peak water pressure and is more effective than the passive post- protection.

Key words: pump-failure water hammer, secondary-protective measure, passive post-protection, active prevention, water column separation, pump station