New concept of air entrainment effect on mitigating cavitation damage
New concept of air entrainment effect on mitigating cavitation damage
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DOI：
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发表时间：
2003
影响因子：
2.4
通讯作者：
Chen Xian
中科院分区：
文献类型：
--
作者：
Chen Xian
采用针式空气浓度探头，对模型和原型的浓度分布、速度场、气泡尺寸的概率分布和气泡的绝对尺寸进行了研究。实验结果表明，由于韦伯数较大，原型的引气能力高于模型。因此，在原型中气泡上浮的过程较慢。原型床面附近出现小气泡的概率和掺气浓度较高。直径小于0.2mm或0.5mm的气泡对减轻空蚀有重要作用。因此，采用小气泡形成的浓度作为评价掺气减蚀效果的标准是合理的。
Concentration distribution, velocity field, probability distribution of bubble dimension and absolute dimension of bubble are studied by using needletype air concentration probes both in model and prototype. It is found that the capability of air entrainment forming small bubble in prototype is higher than in model due to higher Weber number. Thus, the process of bubble buoying up is slower in prototype. The probability of small bubble and concentration of air entrainment near the channel bed is higher in prototype. The bubbles with diameters below the 02mm or 05mm play important role in mitigating the cavitation erosion. Accordingly, it is reasonable to adopt the concentration formed by small bubble as the criterion for appraising the air entrainment effect on mitigating cavitation damage.