高海拔地区气压环境对高速水流空化特性的影响
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摘要
为定量评价高海拔地区的低气压环境对水流空化特性的影响程度,通过理论计算单气核临界压强在不同气压条件下的变化,分析单气核临界压强变化对初生空化数的影响程度,并进行不同海拔高程下水流空化数的敏感性分析。研究成果表明:低气压环境下,气核初生空化数和水流空化数均减小,但水流空化数减小的程度远远大于初生空化数减小的程度,其他条件相同的前提下,高海拔地区的高速水流空化空蚀风险增大。研究结论可为高海拔地区高速水流的空化空蚀设计和评价提供参考。
To quantify the influence of low pressure environment at high altitude on the cavitation characteristics of water flow,single gas nucleus critical pressure under different pressure conditions was theoretically calculated. The influence degree of single gas nucleus critical pressure on the nuclear incipient cavitation number was analyzed,and the sensitivity of flow cavitation number at different elevations was evaluated. Research results showed that,in low pressure environment,both gas nuclear incipient cavitation number and water flow cavitation number decreased,but the water flow cavitation number decreased much more intensively than gas nuclear incipient cavitation number did. On the premise that other conditions are the same,the cavitation erosion risk of high velocity flow is correspondingly high in high-altitude area. The research conclusions provide reference for the design against and evaluation of cavitation erosion of high speed flow in high altitude area.
To quantify the influence of low pressure environment at high altitude on the cavitation characteristics of water flow,single gas nucleus critical pressure under different pressure conditions was theoretically calculated. The influence degree of single gas nucleus critical pressure on the nuclear incipient cavitation number was analyzed,and the sensitivity of flow cavitation number at different elevations was evaluated. Research results showed that,in low pressure environment,both gas nuclear incipient cavitation number and water flow cavitation number decreased,but the water flow cavitation number decreased much more intensively than gas nuclear incipient cavitation number did. On the premise that other conditions are the same,the cavitation erosion risk of high velocity flow is correspondingly high in high-altitude area. The research conclusions provide reference for the design against and evaluation of cavitation erosion of high speed flow in high altitude area.
引文
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[2]吴建华.水利水电工程中的空化与空蚀问题及其研究[C]∥第十八届全国水动力学研讨会文集.北京:海洋出版社,2004:1-18.
[3]朱宗铭,庞佑霞,梁亮,等.环境压力对冲蚀、空蚀交互磨损影响研究[J].机械科学与技术,2013,32(10):1509-1513.
[4]李永梅,王永生,张东.环境压力对高拱坝水垫塘水力特性的影响[J].水利学报,1999,(3):8-12.
[5]严振.论减压试验的相似性[J].水利学报,1983,(3):31-40.
[6]刘继广.水工减压模型试验理论的探讨[J].水利水电技术,2007,38(11):66-70
[7]谢仕群.布仑口—公格尔水电站隧洞施工通风技术[J].人民珠江,2010,(2):58-59
[8]赵明琴,陈祖文.高寒及高海拔地区巨型水轮机组设计探讨[J].人民长江,2013,44(9):93-96.
[9]杨吉健,刘韩生,张为法,等.高海拔地区台阶式溢洪道水力特性研究[J].长江科学院院报,2015,32(10):38-42.
[10]夏叶青,陈志康,上官江.西藏拉洛水利枢纽多功能泄洪隧洞设计研究[J].人民长江,2014,45(23):43-50.
[11]蒙富强,陈军.藏木水电站3#、4#泄洪闸水工模型试验研究[J].中国水运,2012,12(11):160-161.
[12]倪汉根,刘亚坤.水工建筑物的空化与空蚀[M].大连:大连理工大学出版社,2011.