泄洪闸胸墙压坡段的数值模拟
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摘要
采用RNG k-ε紊流数值模型对具有不同坡度的胸墙压坡段的泄洪闸出口水流进行了三维数值模拟.通过数值模拟计算得到了具有4种不同坡度的泄洪闸胸墙压坡段的流线、流速和压力,并对比分析了胸墙压坡段坡度变化对泄洪闸泄流能力、水流脱壁情况、负压分布区域的影响情况.研究结果表明:随着胸墙压坡段坡度的增大,虽然闸口的泄流能力减弱,但是出口水流的脱空长度和脱空高度变小,也即增大胸墙压坡段的坡度使得出口水流的脱壁现象减弱直至消失;胸墙压坡段内的负压最值及负压的分布区域均随着坡度的增大而变小.在泄洪闸胸墙底缘压坡段的设计过程中要避免平坡式链接,可通过合理的方式比选出适用于自身工程的压坡坡度,有利于提高消力池的消能效率,避免压坡段的空化空蚀,从而增强了工程的安全性.研究方法和结果对类似工程的优化设计及安全运行具有一定的指导意义.
The RNG k-ε turbulent numerical model was adopted to simulate the flow characteristic of the breast wall with different slope pressure sections at the exit of the spillway sluice.The streamline,the flow velocity and the pressure were obtained to analyze the influences of different slopes on discharge capacity of the spillway,the phenomenon of current off the wall and the distribution of the negative pressure.The results show that the discharge capacity is weakened,the phenomenon of current off the wall is avoided,and the maximum value and distribution area of the negative pressure are lessened,when the slope of the pressure section becomes sharp.Flat slope type should be avoided in the design process.By a reasonable way,a suitable type selected for a project is beneficial to improve the efficiency of energy dissipation of stilling basin and avoid the cavitation erosion of the pressure slope section,so as to enhance the security of the project.The results and the methods can provide particular guidance to the optimization design and operation of the similar projects.
The RNG k-ε turbulent numerical model was adopted to simulate the flow characteristic of the breast wall with different slope pressure sections at the exit of the spillway sluice.The streamline,the flow velocity and the pressure were obtained to analyze the influences of different slopes on discharge capacity of the spillway,the phenomenon of current off the wall and the distribution of the negative pressure.The results show that the discharge capacity is weakened,the phenomenon of current off the wall is avoided,and the maximum value and distribution area of the negative pressure are lessened,when the slope of the pressure section becomes sharp.Flat slope type should be avoided in the design process.By a reasonable way,a suitable type selected for a project is beneficial to improve the efficiency of energy dissipation of stilling basin and avoid the cavitation erosion of the pressure slope section,so as to enhance the security of the project.The results and the methods can provide particular guidance to the optimization design and operation of the similar projects.
引文
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[9]郭慧敏.浅谈胸墙式泄洪闸体型与泄流量关系[C]//第二届全国水力学与水利信息学学术大会论文集.成都:长江水利委员会,2005.
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[11]HIRT C W,NICHOLS B D.Volume of fluid(VOF)method for the dynamics of free boundary[J].Journal of compute physics,1981,39(1):201-225.
[12]吴持恭.水力学[M].北京:高等教育出版社,2008.
[2]NGUYEN C T,WANG L L,TANG H W.The effect of a curved bed on the discharge equation in a spillway with a breast wall[J].Journal of hydrodynamics,2015,27(2):311-318.
[3]刘世裕.提高带直角胸墙溢洪道泄流能力的研究[J].水利水电技术,1980,11(4):15-17.LIU Shiyu.Discharge capacity study on the parapet walls with rectangular spillway[J].Journal of water resources and hydropower technology,1980,11(4):15-17.(in Chinese)
[4]罗岸,黄智敏,陈卓英.提高带胸墙孔口溢洪道泄流能力的分析与应用[J].广东水利水电,1997,25(4):16-18.LUO An,HUANG Zhimin,CHEN Zhuoying.Discharge capacity analysis and application to improve the parapet walls with orifice spillway[J].Journal of Guangdong water conservancy and hydropower,1997,25(4):16-18.(in Chinese)
[5]连惠萍,赵婷.黄河西霞院水利枢纽泄洪闸水力计算及模型试验[J].黄河水利职业技术学院学报,2012,24(1):4-6.LIAN Huiping,ZHAO Ting.Hydraulic calculation and model test on the sluice gate of Xixiayuan station on the Yellow River[J].Journal of Yellow River Conservancy Technical Institute,2012,24(1):4-6.(in Chinese)
[6]郑伯廉.宝珠寺水电站枢纽泄洪中孔设计的经验[J].陕西水力发电,1989,5(1):16-20.ZHENG Bolian.Design experience on the hub hole of the Baozhu tempt hydropower station[J].Journal of Shaanxi hydropower,1989,5(1):16-20.(in chinese)
[7]王军,陈舟.曹娥江大闸闸室结构设计[J].水利水电技术,2012,43(11):84-86.WANG Jun,CHEN Zhou.Chamber structure design of Cao'e River Sluice[J].Journal of water resources and hydropower technology,2012,43(11):84-86.(in Chinese)
[8]郭雷,马斌,张宗孝,等.地洛水电站枢纽布置优化试验研究[J].西北水力发电,2006,22(5):1-4.GUO Lei,MA Bin,ZHANG Zongxiao,et al.Experimental study on layout optimization of Diluo Hydroelectric Station[J].Journal of northwest hydroelectric power,2006,22(5):1-4.(in Chinese)
[9]郭慧敏.浅谈胸墙式泄洪闸体型与泄流量关系[C]//第二届全国水力学与水利信息学学术大会论文集.成都:长江水利委员会,2005.
[10]YAKHOT V,ORSZAG S A.Development of turbulent models for shear flows by a double expansion technique[J].Phys fluids,1992,4(7):1510-1520.
[11]HIRT C W,NICHOLS B D.Volume of fluid(VOF)method for the dynamics of free boundary[J].Journal of compute physics,1981,39(1):201-225.
[12]吴持恭.水力学[M].北京:高等教育出版社,2008.