This paper investigates the transient behavior and the water hammer in pipelines due to rapid changes in the operation of the group of parallel pumps. After a brief introduction of the water hammer and the boundary conditions related to the transient characteristics of a group of pumps with a parallel arrangement, a time marching second-order finite difference scheme based on the MacCormack method is used to discretize and solve the governing equations. The excellent validity of the present model is evaluated by comparing the obtained results with another well-known solution from previous studies. For example, in case No. 1, which considers the transient behavior of a pumping station with parallel pumps, the maximum absolute difference of the energy head from the proposed model results compared with the benchmark solution is 0.79%. Besides, two other examples are considered, using the present model to investigate the water hammer caused by different scenarios of changing in the operation of the parallel pumps. The results show that the transient characteristics of the system entirely depend on the shutdown and the start-up pattern of the group of pumps. So, variations in the trip and startup times result in a significant change in the pressure increase caused by the water hammer.

本文研究了由于并联泵组运行的快速变化而引起的管道中的瞬态行为和水锤现象。在简要介绍了一组并联泵的瞬态特性相关的水锤和边界条件后，采用基于 MacCormack 方法的时间推进二阶有限差分格式对控制方程进行离散求解. 通过将获得的结果与先前研究中的另一个众所周知的解决方案进行比较，可以评估当前模型的出色有效性。例如，在第 1 种情况下，考虑了具有并联泵的泵站的瞬态行为，与基准解决方案相比，所提出的模型结果的能量水头的最大绝对差异为 0.79%。除了，考虑了另外两个例子，使用本模型来研究由并联泵运行中的不同情况变化引起的水锤。结果表明，系统的瞬态特性完全取决于泵组的停机和启动模式。因此，跳闸和启动时间的变化会导致水锤引起的压力增加的显着变化。