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关于气蚀自1970年投入运行以来,出现了两种气蚀,第一种在叶片背面靠进水边,如图4,最大麻点直径约二毫米,深度不超过一毫米。据资料认为引起这种气蚀的原因是由于净扬程的增加,偏离设计工况点运行的结果。就我站具体情况而言,在三米扬程以内运行占整个运行时间的70%,应该出现腹面气蚀,但是到目前为止,这种气蚀现象并未发生;恰恰相反,出现的却是背面气蚀,这是因为我站长期降低叶轮淹没深度(即减小Hs绝对值)运行的结果,一般在Hs=-1.2～-1.1米(设计为-1.5米)维持的
There have been two kinds of cavitation since the cavitation was put into operation in 1970. The first one came into contact with the water on the back of the blade as shown in Figure 4. The maximum pitting diameter was about two millimeters and the depth was no more than one millimeter. It is believed that the cause of this cavitation is due to the increase of the net lift and the deviation from the design operation point. In my case, ventral cavitation should occur at 70% of the total run time within a three-meter lift, but so far this cavitation did not occur; on the contrary, the back Cavitation, as a result of long-term reduction of impeller inundation depth (ie, reduction of Hs absolute value), is generally maintained at Hs = -1.2 to -1.1 m (designed to be -1.5 m)