南水北调北京段输水系统水力瞬变的控制

Control of Hydraulic Transients in Beijing Section of the Middle Route of South-to-North Water Project

根据北京段输水系统工程布置的特点,研究了事故断电条件下水力瞬变引起的液柱分离现象及其防止措施,提 出了求解空气阀瞬变过程的新模型。研究表明,可以沿线布置空气阀和单向调压井防止瞬变液柱分离破坏。对沿管 线间隔500 m-1 000 m布置空气阀的水力瞬变计算研究发现,过大或者过小的空气阀孔径都是不利的,存在一个抑 制液柱分离冲击压力或者高度真空的最优的空气阀孔径。对采用单向调压井防止液柱分离的研究表明,沿线需要布 置5座,并提出了合理的设置位置和经济参数。

Liquid-column separations in the pipeline of the Beijing Section in Middle Route of South-to-North Water Transfer caused by a power failure are investigated. A new model is presented for solution to the transients of air valves. The analysis indicates that there is an optimal value of the orifice diameter of air valves in control of hydraulic transients. If the air valves with 0. 1 meter of the orifice diameter are placed in every 500m or 1 000 m along the pipeline, the minimum water pressure may be controlled above minus 4. 5m head, which meets the designed requirement. It is also proved that the five single-direction surge tanks can be also used to prevent the pipeline from liquid-column separation.