泵站管路系统水力过渡过程及二次防护措施研究

Study on hydraulic transient in pipeline system of pump station and secondary protective measure

为选择合适的停泵水锤二次防护措施,针对泵站管路系统的特点,运用水锤特征方程组,确定了管道瞬变流的求解方法;同时,采用Bentley Haestad Hammer软件,对重庆市松既长江提水工程子项目——金子山高位水池至上游水库提水工程的水力暂态过程进行了模拟,并对停泵水锤、被动型后保护与主动型水击预防模式引起的管道内水压变化情况进行了计算。计算结果表明:(1)在3种工况条件下,水压的峰值分别为252.80,191.80 m及174.01 m,升压比分别为1.50,1.44及1.05;(2)水泵停机时间分别为3.74,3.77 s及4.60 s,水泵均未出现反转情况;(3)被动型后保护瞬态最高水头曲线呈弓形,而主动型水击预防瞬态的最高水头曲线接近正常水头线;(4)3种工况下的阀门出口处压力波动范围分别为71.4~254.8,70.7~181.0 m及46.0~174.0 m,而且主动型的水击预防模式水泵出口的波动最为缓和。主动型水击预防可以最大幅度地降低水锤的升压峰值,是更完善的二次防护措施。

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.