Improving the anti cavitation performance of the pump :
1、降低必需汽蚀余量
1. reduce the necessary cavitation margin:
1).采用双吸式叶轮的水泵。由于双吸泵的汽蚀余量Δhc比单级单吸泵的汽蚀余量Δhc小，对于转速n和流量Q相同的泵，尽量采用双吸式叶轮。
1). The double suction impeller pump. The double suction pump NPSH delta HC than single stage single suction pump NPSH HC, N and Q for the same speed flow pump, adopt double suction impeller.
2).适当加大叶轮进口直径及增大叶片入口宽度。水泵当叶轮进口直径和叶片入口宽度增大时，其叶轮进口绝对速度和相对速度均减小，可知泵的临界汽蚀余量降低。但此时叶轮进口处的减漏环面积增大，泄露量增加，泵的容积效率会降低。
2). Appropriately increasing the inlet diameter of the impeller and increasing the inlet width of the blade. When the impeller inlet diameter and the inlet width increase, the absolute velocity and relative velocity of the impeller inlet are decreased, and the critical cavitation margin of the pump is decreased. However, at this time the impeller inlet area of the reduction of the area increases, leakage increased, the volume efficiency of the pump will be reduced.
3).叶轮前加设诱导轮。在离心泵叶轮前设置诱导轮。诱导轮与泵的叶运转，其产生的压力轮同轴组装后一起运转，其产生的压力对叶轮入口增压，提高泵的抗汽蚀性能。但加设诱导轮，会使水泵性能不稳定，因此，尚需对其进行进一步的探索和研究。
3) impeller before the addition of inducer. Inducer before impeller of centrifugal pump impeller. The impeller and the pump vane pump, the pressure generated by the coaxial assembly of the wheel running together, the pressure generated by the impeller inlet pressure, improve pump cavitation performance. However, the addition of inducer, will make the pump performance is not stable, therefore, it is necessary to further explore and research.
2、提高过流部件材料的抗汽蚀能力为了减轻汽蚀对水泵过流部件的损坏，延长其使用寿命，往往选用抗汽蚀性能较强的材料。如采用铸锰、青铜、不锈钢及合金钢等材料铸造叶轮；或用聚合物涂复或激光喷镀过流部件表面以抵抗汽蚀破坏。另外，对过流部件表面进行精加工，提高其光洁度，也可减轻汽蚀的危害。
2. Improve the anti cavitation ability of the flow component material in order to reduce the cavitation damage to the pump flow parts, to extend its service life, often choose the material with strong anti cavitation performance. Such as cast manganese, bronze, stainless steel and alloy steel casting impeller; or with polymer coating or laser spray plating parts surface to resist cavitation damage. In addition, on the surface of the flow parts finishing, improve its finish, but also to reduce the harm of cavitation.
提高进水装置的防汽蚀能力
Anti cavitation ability of the water inlet device:
汽蚀余量是与进水装置和管路系统有密切关系，因此应设计良好的进水装置，尽可能地提高泵进口的汽蚀余量，以满足泵内动压降的要求。
The cavitation margin is closely related with the water inlet device and the pipeline system, so it should be designed to be a good water inlet device, so as to improve the pump inlet's cavitation margin, so as to meet the requirements of the dynamic pressure drop in the pump.
1).合理确定水泵的吸水高度。由于水泵一般都在非设计工况下运行，因此应充分考虑水泵工作中可能遇到的各种工况，所确定的吸水高度在任何工况下都应满足水泵吸水性能的要求。
1. Reasonably determine the water absorption of the pump. The pumps are generally in non design condition, it should fully consider the various conditions that may be encountered in the work of the water pump, the determined height in any condition should meet the requirements of water pump performance.
2).选配合理的进水管道。尽可能减少进水管道长度及不必要的管道附件，适当加大进水管径，以减小进水管的水力损失，提高泵进口的汽蚀余量。对于大、中型轴流泵，进水管道内的水流流速和压力尽可能均匀分布，将有利于防止汽蚀的发生。
2. Optional water inlet pipe. As far as possible to reduce the length of the inlet pipe and unnecessary pipe attachment, appropriate increase in the inlet pipe diameter, in order to reduce the hydraulic loss of the inlet pipe, improve the pump inlet cavitation. For large and medium axial flow pumps, the distribution of flow velocity and pressure in the inlet pipe can be evenly distributed, which will be beneficial to prevent the occurrence of cavitation.
3).设计良好的进水池。良好的进水池不仅可以减小池中水位的降落，减小进水管口的阻力系数，而且池中水面平稳不产生漩涡。可避免空气进入泵内，防止汽蚀过早地发生。
3) well designed into the pool. Fall into the pool of good can not only reduce the water level in the pond, reduce the resistance coefficient of inlet, and the water in the pool is stable without swirl. Can avoid the air into the pump, to prevent the occurrence of cavitation premature.
运行管理中可采取的措施
Measures to be taken in operation management :
1.尽量使水泵在设计工况附件运行。可跟据泵站的具体条件，水泵采用变阀、变速、变角等调节措施，来防止水泵运行工况偏离设计工况过远。
1. As far as possible to make the pump in the design of the operating conditions of the annex. According to the specific conditions of the pump station, the pump using variable valve, variable speed, variable angle and other regulatory measures to prevent pump operating conditions deviate from the design conditions too far.
2. 控制水泵实际转速高于设计转速的幅度。由于必须汽蚀余量与转速的平方成正比，转速过高时，不仅使必须汽蚀余量大幅增加，而且使有效汽蚀余量减小。
2. The actual speed of the pump is higher than the design speed. Due to the need to be proportional to the square of the speed and the speed of the rotating speed is too high, not only to reduce the need for a substantial increase in cavitation margin, but also to reduce the effective cavitation margin.
3. 水泵在运行中发生汽蚀时，可采用水泵进水口充入少量空气或高压水流的办法，来减轻或避免汽蚀危害。
3. Pump cavitation in the operation, the water inlet of the water pump filled with a small amount of air or high-pressure water way, to reduce or avoid cavitation damage.
