Axial-Flow Pump with Enhanced Cavitation Erosion Resistance

Axial-flow pumps, in addition to providing high anti-cavitation properties, must have anti-erosion properties ensure the required lifetime of pump. Erosion damage surfaces occurs when net positive suction head (NPSH) significantly exceeds its critical value. The object study this article is axial-flow pump with a specific speed 600 two alternatives: № 1 and 2. By analysis flow impeller blade systems, ratio value between NPSH, which ensures absence erosion, NPSH3, at operational failure occurs, was determined. Impeller variant did not provide ratio. 2 had higher cavitation qualities, achieved for it. Energy, cavitation, erosion characteristics rotational frequency n = 2000 rpm were investigated. Easily breakable paint coatings used accelerated erosion. experiment carried out three different rates confirmed assumptions made—the affected by optimum rate. Patterns zones accompanied calculations vapor impeller. At less than optimum, disruptions occurred appeared behind region. As result, condition ensuring erosion-free an axial obtained, NPSH/NPSH3 > 2.5. Recommendations on designing part also obtained.