掺气泡对空泡影响的高速摄影分析  

High speed photographic analysis of effect of aeration bubbles on cavitation bubbles

作　　者：俞小伟[1] 董志勇[1] 韩伟[1] 王立[1] 颜效凡[1] 

机构地区：[1]浙江工业大学建筑工程学院,浙江杭州310032

出　　处：《浙江工业大学学报》2011年第3期268-272,共5页Journal of Zhejiang University of Technology

基　　金：国家自然科学基金资助项目(50879078)

摘　　要：为解决高速水流空化产生的空蚀破坏,常在低压区或易发生空蚀部位上游设置掺气设施强迫掺气,而高速水流掺气减蚀的机理涉及空泡动力学问题.通过在直流式水洞中用高速摄影技术对半圆柱突体的空化特性进行观察分析,测量了半圆柱突体后空化区不同直径掺气孔及掺气体积分数下压力和空化数的变化.揭示了半圆柱突体后空化云的形态、随流运动的演变情况,不同直径掺气泡对空化云及空泡和掺气泡相互作用的影响.试验结果表明在流速v=11.67 m/s,掺气量分别为0.6,0.8,1.0 m3/h的情况下,高10 mm,底部直径为6 mm的半圆柱突体后2 mm掺气孔的空化数会达到最大值,并且最佳掺气孔径会随掺气体积分数的增加而减小.In order to solve the problem of cavitation damage due to high velocity flow,an aerator is usually used to aerate air into low-pressure region or upper region that cavitation damage occurs.And the mechanism of cavitation control by aeration in high-velocity flow involves in bubble dynamics.Cavitation characteristics of semi-cylindrical irregularity were observed by high speed photography in a noncirculating water tunnel.Variations of pressure and cavitation number within cavitation zone behind semi-cylindrical irregularities with both diameters of aeration hole and gas concentrations were measured.Regimes of cavitation clouds,evolutions and effects of different aeration bubble sizes on interaction between cavitation and aeration bubbles were photographically observed.Under the conditions of v=11.67 m/s,Qa=0.6 m3/h,0.8 m3/h,1.0 m3/h,and 10 mm high semi-cylindrical irregularity with 6mm in diameter of bottom,the experimental results showed that cavitation number of 2 mm aeration hole could reach the maximum.And the optimal diameter of aeration hole decreased with increase in gas concentration.

关 键 词：半圆柱突体 空泡 掺气泡 高速摄影技术 

分 类 号：TV131.34[水利工程—水力学及河流动力学]