黏性泥沙粒径对高速水流空蚀影响的试验研究  

An experimental study of effect of cohesive sediment grain sizeon cavitation erosion in high-velocity flow

作　　者：董志勇[1] 韩岩 曾团 贾代鲁 DONG Zhiyong;HAN Yan;ZENG Tuan;JIA Dailu(College of Civil Engineering,Zhejiang University of Technology,Hangzhou 310023,China)

机构地区：[1]浙江工业大学土木工程学院,浙江杭州310023

出　　处：《浙江工业大学学报》2023年第2期199-206,共8页Journal of Zhejiang University of Technology

基　　金：国家自然科学基金资助项目(51979248)。

摘　　要：在小型循环式水洞中对黏性泥沙粒径对高速水流空蚀影响的机理开展了试验研究。在水洞的水箱内筒中人工配制了含沙量s为12 kg/m^(3),中值粒径d 50分别为0.087,0.240,0.403 mm的3种黏性泥沙水样。为探究中值粒径对空蚀的影响,制作了不同配合比的混凝土试件,在空蚀区安装混凝土试件,使混凝土试件在不同中值粒径工况下进行4 h的空蚀试验,通过混凝土试件每小时的质量损失来表征空蚀量。试验结果表明:在含沙量s为12 kg/m^(3)工况下,水洞空蚀区各测点的压强和空化数随中值粒径的增加而升高,促进了空蚀的发生;当混凝土试件配合比、龄期不变时,混凝土试件的空蚀程度随中值粒径的增大而加深,空蚀范围扩大;当喉部流速提高时,空蚀则进一步扩大。较高强度配合比(水灰比=0.40,灰砂比=1.5)的混凝土试件在不同中值粒径时的抗空蚀能力优于较低强度配合比(水灰比=0.45,灰砂比=2.0)的混凝土试件。The effect of cohesive sediment grain size on cavitation erosion in high velocity flow was studied experimentally in a small circulating water tunnel.Three kinds of cohesive sediment flow with sediment concentration s=12 kg/m^(3) and median sizes d 50=0.087,0.240,0.403 mm was prepared manually in the inner tank of the water tunnel and concrete specimens with different mix proportions were poured to investigate the effect of median size on cavitation erosion,which were installed in the cavitation erosion zone.The concrete specimens were carried out tests of cavitation erosion at different median sizes for 4 hours.The weight loss of concrete specimens per hour was used to represent the cavitation erosion rate.The experimental results showed that for a sediment concentration of s=12 kg/m^(3),the time-averaged pressure and the cavitation number in the cavitation erosion zone increase with the increase in median size,propelling the occurrence of cavitation erosion.For the same mix proportion and age,the cavitation erosion extent of concrete specimens is aggravated with an increase in median size,and the cavitation erosion area increases.The cavitation erosion extent increases with an increase in throat velocity.The anti-cavitation erosion capacity of concrete specimens with higher strengths(water-cement ratio=0.40 and cement-sand ratio=1.5)is greater than that with lower strengths(water-cement ratio=0.45 and cement-sand ratio=2.0)at different median sizes.

关 键 词：黏性泥沙 高速水流 中值粒径 空蚀 混凝土试件 

分 类 号：TV131.3[水利工程—水力学及河流动力学]