长距离输水工程末端关阀方式对水锤防护的影响

为考察管线末端关阀方式对长距离输水工程水锤防护的影响,针对有压输水管道的特点,运用水锤特征方程组确定了关阀水锤的求解方法,并采用Bentley Haestad Hammer软件对重庆市铜罐驿区域供水项目TIWS.CP2标段水力暂态过程进行了模拟,计算了末端不同关阀模式引起的管道内水压及空腔体积变化。计算结果表明:10 s快速关阀、500 s线性关阀、两阶段关阀3种工况条件下水压峰值分别为1.69,1.15 MPa和0.69 MPa,升压比分别为7.00,4.52及2.56,500 s线性关阀与两阶段关阀水压峰值较10 s快速关阀分别降低了32.0%与59.2%;快速关阀时出现负压,并产生了较大空腔区,水锤衰减作用不明显;3种关阀模式中只有两阶段关阀产生水压峰值满足管道的承压能力。通过对3种关阀模式的水锤效应比较,可以认为两阶段关阀是管线末端关阀方式的最佳选择。

Effect of terminal valve closing mode on water hammer protection in long-distance pipeline water diversion project

In order to study the effect of terminal valve closing mode on water hammer protection for long-distance water supply pipeline, the solving method of valve closing induced hammer was determined by hammer characteristic equations on the basis of analyzing the characteristics of pressure pipe. Moreover, Bentley Haestad Hammer software was adopted to simulate the hydraulic transient process of Tongyuanyi regional water supply project (TIWS.CP2 bid section) in Chongqing City, the pressure variation and cavity volume during hydraulic transient process caused by different terminal valve closure modes was revealed. The calculation results showed that in 3 different terminal valve closure modes of quick closure in 10s, linear closure in 500s and two-stage closure, the corresponding peak water pressure is 1.69, 1.15 MPa and 0.69MPa, and the upsurge ratio is 7.00, 4.52 and 2.56. The water pressure peaks of linear closure in 500s and two-stage closure decreased by 31.9% and 59.2% respectively compared with the quick closure in 10s. Negative pressure and large cavity zone emerged in quick closure mode, and the water hammer attenuation effect was not significant. Only the water pressure peak of two-stage closure mode can meet the requirements of bearing pressure capacity of pipeline, so it was considered as the optimum choice.