离心泵启动和停机等问题归根结底是离心泵水力性能随转速变化的瞬态过程。以常用的IS125 型管道离心水泵为例,在数值模拟中采用叶轮转速随时间变化的CFD 计算方法,研究离心泵开机、停机等变转速过程中水泵内部流动状态以及外特性的动态变化。整个模拟计算过程包括泵启动、正常运行、停机和停机后4 个阶段。模拟计算得到了4 个阶段不同时刻泵内流场分布状况,得到了4个阶段流量扬程等水泵外特性参数随时间的变化规律,可为改善水泵的设计性能和实际运行性能提供理论依据。
The starting and stopping processes of a centrifugal pump are essentially transient processes, where the hydraulic performance changes with the rotational speed of the pump. In this paper, the CFD simulation is made by changing the impeller rotational speed over time for the type IS125 centrifugal pump to study the transient internal flow field and the external performance of the pump during starting and stopping processes. The entire simulation consists of four stages, including the startup, the normal running, the stopping and post-stopping of the pump. The variations of the flow field are obtained from the transient simulation. The flow-rate, the head and other external performance parameters against time are also obtained, which can be used in pump designs and actual operations.
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