渣浆泵的汽蚀及预防措施
一、产生汽蚀的机理及危害

1. 汽蚀的机理

离心泵内的液体在进入叶轮叶片之前压力一直下降，进入叶轮叶片后液体获得能量,压力升高。泵内压力最低点位于叶片入口附近的k截面处， 若其局部压力Px小于此处温度下该液体的饱和蒸气压p，液体就要汽化，同时溶解在该液体中的气体也逸出，形成大量小气泡，如图1-15所示，从而使得液流的过流面积减小，流动损失增大，导致泵内流量减小,扬程变小，效率降低,性能恶化。
    当气泡随液体流到叶轮内压力较高处时,外面液体压力高于气泡内的压力，则气泡会凝结溃灭，形成空穴。瞬间，周围的液体以极高的速度向空穴冲击，造成液体互相相撞，使局部压力骤然剧增，有时可达数百个大气压，阻碍液体正常流动，严重时会造成断流。
    如果这些气泡在流道壁面附近溃灭，则周围的液体以极高频率和速度连续撞击金属表面，金属表面会因冲击、疲芳而剥落。若气泡内还夹杂某些活性气体(如氧气等)，它们借助蒸气凝结时放出的热量(局部温度可达200~300C)，对金属起电化学腐蚀作用，这就更会加快金属剥落速度。渣浆泵厂家
    上述这种液体汽化、凝结形成高频冲击负荷，造成金属材料的机械剥落和电化学腐蚀的综合现象统称为汽蚀现象,通常也称为空化或空蚀。

Cavitation of slurry pump and preventive measures

1、 Mechanism and harm of cavitation

1. Mechanism of cavitation

The pressure of the liquid in the centrifugal pump has been decreasing before it enters the impeller blade. After entering the impeller blade, the liquid obtains energy and the pressure increases. The lowest point of the pressure in the pump is located at the section K near the blade inlet. If the local pressure PX is lower than the saturated vapor pressure P of the liquid at this temperature, the liquid will vaporize. At the same time, the gas dissolved in the liquid will also escape, forming a large number of small bubbles, as shown in Figure 1-15, so as to reduce the flow area, increase the flow loss, reduce the flow rate and head in the pump, Efficiency is reduced and performance is deteriorated.

When the bubble flows with the liquid to the impeller with high internal pressure, the external liquid pressure is higher than the internal pressure of the bubble, the bubble will condense and collapse, forming a cavity. In an instant, the surrounding liquid impacts the hole at a very high speed, causing the liquid to collide with each other, suddenly increasing the local pressure, sometimes up to hundreds of atmospheric pressure, hindering the normal flow of the liquid, and even breaking the flow.

If these bubbles collapse near the wall of the flow passage, the surrounding liquid continuously impacts the metal surface at a very high frequency and speed, and the metal surface will peel off due to impact and fatigue. If there are some active gases (such as oxygen) in the bubble, they will give off heat (local temperature can be up to 200 ~ 300C) when they condense with the help of steam, which will play an electrochemical corrosion role on the metal, which will accelerate the metal peeling rate. Slurry pump manufacturer

This kind of liquid vaporizes and condenses to form high-frequency impact load, resulting in mechanical peeling and electrochemical corrosion of metal materials, which are collectively referred to as cavitation phenomenon, usually referred to as cavitation or cavitation.