注气阀与拍门削减两处断流弥合水锤的研究

On Reduction of Waterhammer Due to Cavities Separation at Two Points by Intercepted Air Valve and Board

试验表明 ,泵系统瞬变过程中在两处断流处单独注气 ,或在系统末端仅设置升降式拍门 ,或同时进行注气和拍门操作 ,都可削减两处的断流弥合升压 ,但削减压力的幅度及各处断流的长度不同 :单独采用注气措施对削减系统首端的断流弥合水锤压力最有效 (aA ≈ 0 .80 ) ,而单独用拍门对系统膝部的削峰比最高 (aB ≈ 0 .90 ～ 0 .95 ) ,同时采取注气加拍门措施 ,对首端的削峰比略有提高 (≈ 0 .82 ) ,但膝部却不及单独用拍门的削峰效果好 ;采用注气和拍门措施都会使两处的断流长度加长 ,但两处的断流长度与其削峰比无直接相关关系 .

The experiments indicate that the waterhammer due to separated cavities collapsing at two points can be reduced by intercepting air,or installing elevated-dropped board or,adopting them simultaneously,but the range of pressure reduction and eparation length is distinct.It is most effective in reducing waterhammer at head of the system by intercepted air only(a A≈0.80), and the maximum crest-cut ratio(a B≈0.90～0.95) is achieved at knees by board. If they are adopted at the same time, the crest-cut ratio at head rose slightly, but the effectiveness is less than by using board only at knees, and the separation length at two points is longer than that of no protection steps adopted, and there is no direct relationship between the crest-cut ratio and sepatation length.