南水北调北京段输水系统水力瞬变的控制

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。计算研究表明，可以采用沿线布置空气阀和单向调压井防止瞬变液柱分离破坏。通过对沿管线间隔500-1000m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，南水北调北京段沿线需要布置5座，并提出了合理的设置位置和经济参数。

Control of pipeline hydraulie transients in South to North Water Transfer Project

Liquid-column separations in pipeline of Beijing section in the Middle Route of South to North Water Transfer Project caused by power failure are investigated. A new model is presented to solve the transients of air valves. The analysis indicates that there is an optimal orifice diameter of the air valves for controlling the hydraulic transients. If the air valves with 0.1m diameter orifice are placed in every 500m to 1000m interval along the pipeline, the minimum water pressure may be controlled higher than -4.5m water head, which meets the designed requirement. It is also proved that the designed five unidirectional surge tanks can be also used to prevent the pipeline from liquid-column separation.