水工建筑物水气两相流数值模拟及试验研究
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摘要
水气两相流是一种复杂而重要的流动现象,许多学者耗费了的大量精力对其进行了研究。由于存在着相间质量、动量、能量及热量的交换,且具有各向异性的特点,水气两相流的动力特性比单质水动力学特性要复杂得多。
本文首先对已有的水气两相流研究成果进行了综述,在此基础上深入探讨了水气两相流数值模拟的理论和方法,通过数值模拟和物理模型试验相结合的方法对台阶坝泄流和设置掺气坎的底孔泄流水力特性进行了研究,主要成果有:
1.采用二维k ?ε双方程紊流模型,对台阶坝面的流态、流速、水面线以及坝面压力和水流的掺气情况进行了模拟,并由此计算了台阶坝的消能率。计算中自由表面采用VOF方法处理,边界条件的处理使用了任意网格差分法,数值求解使用了点隐式高斯—塞德尔迭代方法。物理模型试验验证表明,对台阶坝面水流的数值模拟是可行的。
2.对台阶坝面水流数值模拟结果表明,水流流过一定台阶后开始掺气,与光面坝相比,坝面水深增加,流速减小,产生空化空蚀的风险降低,而消能率大大增加。
3.采用三维k ?ε双方程紊流模型,对泄洪底孔的水力特性进行了数值模拟。计算分析了泄洪底孔有压短管压力、跌坎下游的掺气空腔长度、高度、通气孔的通气量、消力池流速流态和压力等水力参数。物理模型试验验证表明,对泄洪底孔泄流的数值模拟也是可行的。
Water-air two-phase flow is a complicated and important phenomenon which has attracted many scholars globally spending a lot of time on mechanism study. Due to the mutual exchanges among weight, momentum, energy, and heat that exists in the flow process, the dynamic characteristics of water-air two-phase flow is a bit different from that of water flow.
In this paper step energy dissipation and bottom outlet flood discharge energy dissipation with air hole had been studied by the method of the combination of numerical simulation and physical model tests. And the main results are as follows:
1. The thesis used the 2D double-equation turbulence flow numerical calculation method. The whole process of the water-air two-phase flow was simulated numerically in the cases of flow pattern, velocity, water surface line on the stepped spillway as well as the step pressure and c on the surface of the spillway. Then the rate of energy-dissipation of the stepped spillway was calculated. The simulation method was called the free-surface simulation method, in which the VOF method were used. And the arbitrary mesh-finite difference method was used in the boundary condition solution. The numerical solution was made out with point Implicit Gauss - Seidel iterative method.According to the analysis of the results between numerical simulation and the physical simulation, the numerical simulation was feasible.
2. The numerical simulation for the stepped spillway illustrated that the flow aeration starede to increase on the surface of the spillway, and the velocity decreased whereas the rate of energy-dissipation increased. Therefore, the risk of the cavitation decresed.
3. The three-dimensional numerical simulation was used in the research of the hydraulic characteristics , which simulated the length, the height, the volume of the hole, depth distribution, velocity in the home as well as the pressure of the aeration hole in the flood hole's aeration bottom. According to the comparative analysis with the physical experiments, the numerical simulation was feasible too.
本文首先对已有的水气两相流研究成果进行了综述,在此基础上深入探讨了水气两相流数值模拟的理论和方法,通过数值模拟和物理模型试验相结合的方法对台阶坝泄流和设置掺气坎的底孔泄流水力特性进行了研究,主要成果有:
1.采用二维k ?ε双方程紊流模型,对台阶坝面的流态、流速、水面线以及坝面压力和水流的掺气情况进行了模拟,并由此计算了台阶坝的消能率。计算中自由表面采用VOF方法处理,边界条件的处理使用了任意网格差分法,数值求解使用了点隐式高斯—塞德尔迭代方法。物理模型试验验证表明,对台阶坝面水流的数值模拟是可行的。
2.对台阶坝面水流数值模拟结果表明,水流流过一定台阶后开始掺气,与光面坝相比,坝面水深增加,流速减小,产生空化空蚀的风险降低,而消能率大大增加。
3.采用三维k ?ε双方程紊流模型,对泄洪底孔的水力特性进行了数值模拟。计算分析了泄洪底孔有压短管压力、跌坎下游的掺气空腔长度、高度、通气孔的通气量、消力池流速流态和压力等水力参数。物理模型试验验证表明,对泄洪底孔泄流的数值模拟也是可行的。
Water-air two-phase flow is a complicated and important phenomenon which has attracted many scholars globally spending a lot of time on mechanism study. Due to the mutual exchanges among weight, momentum, energy, and heat that exists in the flow process, the dynamic characteristics of water-air two-phase flow is a bit different from that of water flow.
In this paper step energy dissipation and bottom outlet flood discharge energy dissipation with air hole had been studied by the method of the combination of numerical simulation and physical model tests. And the main results are as follows:
1. The thesis used the 2D double-equation turbulence flow numerical calculation method. The whole process of the water-air two-phase flow was simulated numerically in the cases of flow pattern, velocity, water surface line on the stepped spillway as well as the step pressure and c on the surface of the spillway. Then the rate of energy-dissipation of the stepped spillway was calculated. The simulation method was called the free-surface simulation method, in which the VOF method were used. And the arbitrary mesh-finite difference method was used in the boundary condition solution. The numerical solution was made out with point Implicit Gauss - Seidel iterative method.According to the analysis of the results between numerical simulation and the physical simulation, the numerical simulation was feasible.
2. The numerical simulation for the stepped spillway illustrated that the flow aeration starede to increase on the surface of the spillway, and the velocity decreased whereas the rate of energy-dissipation increased. Therefore, the risk of the cavitation decresed.
3. The three-dimensional numerical simulation was used in the research of the hydraulic characteristics , which simulated the length, the height, the volume of the hole, depth distribution, velocity in the home as well as the pressure of the aeration hole in the flood hole's aeration bottom. According to the comparative analysis with the physical experiments, the numerical simulation was feasible too.
引文
[1] Boussinesq J,Essay on the theory of flow water,Mem.Acad.Sci.,Paris,1877
[2] Tangren R.F,Dodge C.H&Seifert H.S,Compressibility effects in two-phase flow,J.Appl.Phys.,1949
[3] Streeter V.L,Handbook of Fluid Dynamics,McGraw-Hill,New York,1961
[4] Murray J.Q,On the mathematics of fluidization,part I,Fundamental equations and wave propagation,J.Fluid Mech.,1965
[5] Pai S.I,Two-Phase Flow,Vieweg-Verlag,Braunschweig,1977
[6] Rudinger G.,Fundamentals of Gas-Particle Flow,Elsevier Scientific Publishing Co,Amsterdam,1980
[7]柏实义,两相流动,国防工业出版社[M],1985
[8]张远君等,两相流体力学[M],北京航空学院出版社
[9] Hetsroni G.(ed),Handbook of Multiphase Systems,Hemisphere Publishing Co,Washington,1982
[10]刘大有,两相流体动力学[M],高等教育出版社,1993.9
[11]周建军,明渠自掺气水流掺气浓度分布研究[J],水动力学研究与进展,1993.9
[12]吴持恭、杨永森,空中自由射流断面含水浓度分布规律研究[J],1994.7
[13]董志勇,高速掺气水流可压缩流特性[J],水力发电学报,1998
[14]赵建福、李炜,掺气水流相间作用力模型分析[J],水动力学研究与进展,1998.12
[15]赵建福、李炜,高速掺气水流的压缩性准则[J],水利学报,1999.5
[16]吴持恭,明渠水气两相流[J],成都科技大学出版社,1989.6
[17]杨永森,强迫掺气水流的数学模型[R],清华大学博士后出站总结报告,1993.7
[18]黄继汤,空化于空蚀的原理及应用[M],清华大学出版社,1991
[19]掺气减蚀机理和空腔长度、掺气量及保护长度计算方法的研究,国家“八五”科技攻关报告[R],大连理工大学,1992.11
[20]谢省宗、陈文学,掺气水流掺气浓度缩尺影响的估计[J],水利学报,2005.12
[21]董志勇、居文杰、吕阳泉、丁春生,减免空蚀掺气浓度的试验研究[J],水力发电学报,2006.6
[22]杨永森、吴持恭,通气槽挑射水流掺气特性的研究[J],水利学报,1992.4
[23]杨永森、陈长植、于琪洋,掺气槽上射流挟气量的数学模型[J],水利学报,1996.3
[24]苑明顺,陡槽自然掺气发展区含气浓度分布计算[J],水利学报,1992.10
[25]王鹏举,明渠气一水两相混合物掺气浓度分布的计算[J],水利学报,1997.2
[26] LiuDa-ming、WangBao-an,Model Evaluation of Air Demand of Aerators,Int Symp. on Hydr Res.In Nature and Laboratory,Wuhan,China,1992
[27]夏维洪,高速掺气水流的模型相似问题[J],水动力学研究与进展, 1997.3
[28]潘水波、邵瑛瑛、时启隧,通气挑坎射流的挟气能力[J],水利学报,1980
[29]许唯临,紊流代数应力模型在水力学中的应用研究[D],成都科技大学博士学位论,1991
[30]潭立新,水气二相流数值模拟研究[D],四川大学博士学位论,1991
[31]吴持恭、温贤云等,自由面重力流的数值理论和方法[J],成都科技大学出版社,1993.10
[32] A.R.ZARRATI,Mathematical Modelling of Air-water Mixture in Open Channels,J.Hydraulic Research,Vol.33 1994,No.5
[33]金忠青,N—S方程的数值解和紊流模型[M],河海大学出版社,1989.6
[34]汪德瓘,计算水力学理论与应用[M],河海大学出版社,1989(9)
[35]蔡树棠、范正翘、陈越南,两相流基本方程[J],应用数学和力学,第7卷第6期,1986.6
[36]石教豪、韩继斌、姜治兵,马来西亚沐若水电站泄洪消能(砼重力坝方案)研究报告[R],长江水利委员会长江科学院,2007.10
[37]汤升才、金峰、石教豪,台阶式溢流坝的试验研究与消能率计算[J],人民长江,2008.6
[38]严伟、韩继斌、廖宁,亭子口水利枢纽底孔(突扩方案)水工断面模型试验研究报告[R],长江水利委员会长江科学院,2008.10
[39]刁明军,高坝大流量泄洪消能数值模拟及试验研究[D],四川大学博士学位论文,2004.11
[40] N.L.de.S本托,S.H奈德特,溢洪道掺气水流模型——原型的相似性[M],国际水工模型试验会议译文选集,泄水建筑物高速水流情报网编译, 1984.1
[41]夏毓常,通气减蚀设施原型、模型通气量空腔长度对比分析[M],水工模型缩尺效应学术会讨论文集,长江科学院,1991.4
[2] Tangren R.F,Dodge C.H&Seifert H.S,Compressibility effects in two-phase flow,J.Appl.Phys.,1949
[3] Streeter V.L,Handbook of Fluid Dynamics,McGraw-Hill,New York,1961
[4] Murray J.Q,On the mathematics of fluidization,part I,Fundamental equations and wave propagation,J.Fluid Mech.,1965
[5] Pai S.I,Two-Phase Flow,Vieweg-Verlag,Braunschweig,1977
[6] Rudinger G.,Fundamentals of Gas-Particle Flow,Elsevier Scientific Publishing Co,Amsterdam,1980
[7]柏实义,两相流动,国防工业出版社[M],1985
[8]张远君等,两相流体力学[M],北京航空学院出版社
[9] Hetsroni G.(ed),Handbook of Multiphase Systems,Hemisphere Publishing Co,Washington,1982
[10]刘大有,两相流体动力学[M],高等教育出版社,1993.9
[11]周建军,明渠自掺气水流掺气浓度分布研究[J],水动力学研究与进展,1993.9
[12]吴持恭、杨永森,空中自由射流断面含水浓度分布规律研究[J],1994.7
[13]董志勇,高速掺气水流可压缩流特性[J],水力发电学报,1998
[14]赵建福、李炜,掺气水流相间作用力模型分析[J],水动力学研究与进展,1998.12
[15]赵建福、李炜,高速掺气水流的压缩性准则[J],水利学报,1999.5
[16]吴持恭,明渠水气两相流[J],成都科技大学出版社,1989.6
[17]杨永森,强迫掺气水流的数学模型[R],清华大学博士后出站总结报告,1993.7
[18]黄继汤,空化于空蚀的原理及应用[M],清华大学出版社,1991
[19]掺气减蚀机理和空腔长度、掺气量及保护长度计算方法的研究,国家“八五”科技攻关报告[R],大连理工大学,1992.11
[20]谢省宗、陈文学,掺气水流掺气浓度缩尺影响的估计[J],水利学报,2005.12
[21]董志勇、居文杰、吕阳泉、丁春生,减免空蚀掺气浓度的试验研究[J],水力发电学报,2006.6
[22]杨永森、吴持恭,通气槽挑射水流掺气特性的研究[J],水利学报,1992.4
[23]杨永森、陈长植、于琪洋,掺气槽上射流挟气量的数学模型[J],水利学报,1996.3
[24]苑明顺,陡槽自然掺气发展区含气浓度分布计算[J],水利学报,1992.10
[25]王鹏举,明渠气一水两相混合物掺气浓度分布的计算[J],水利学报,1997.2
[26] LiuDa-ming、WangBao-an,Model Evaluation of Air Demand of Aerators,Int Symp. on Hydr Res.In Nature and Laboratory,Wuhan,China,1992
[27]夏维洪,高速掺气水流的模型相似问题[J],水动力学研究与进展, 1997.3
[28]潘水波、邵瑛瑛、时启隧,通气挑坎射流的挟气能力[J],水利学报,1980
[29]许唯临,紊流代数应力模型在水力学中的应用研究[D],成都科技大学博士学位论,1991
[30]潭立新,水气二相流数值模拟研究[D],四川大学博士学位论,1991
[31]吴持恭、温贤云等,自由面重力流的数值理论和方法[J],成都科技大学出版社,1993.10
[32] A.R.ZARRATI,Mathematical Modelling of Air-water Mixture in Open Channels,J.Hydraulic Research,Vol.33 1994,No.5
[33]金忠青,N—S方程的数值解和紊流模型[M],河海大学出版社,1989.6
[34]汪德瓘,计算水力学理论与应用[M],河海大学出版社,1989(9)
[35]蔡树棠、范正翘、陈越南,两相流基本方程[J],应用数学和力学,第7卷第6期,1986.6
[36]石教豪、韩继斌、姜治兵,马来西亚沐若水电站泄洪消能(砼重力坝方案)研究报告[R],长江水利委员会长江科学院,2007.10
[37]汤升才、金峰、石教豪,台阶式溢流坝的试验研究与消能率计算[J],人民长江,2008.6
[38]严伟、韩继斌、廖宁,亭子口水利枢纽底孔(突扩方案)水工断面模型试验研究报告[R],长江水利委员会长江科学院,2008.10
[39]刁明军,高坝大流量泄洪消能数值模拟及试验研究[D],四川大学博士学位论文,2004.11
[40] N.L.de.S本托,S.H奈德特,溢洪道掺气水流模型——原型的相似性[M],国际水工模型试验会议译文选集,泄水建筑物高速水流情报网编译, 1984.1
[41]夏毓常,通气减蚀设施原型、模型通气量空腔长度对比分析[M],水工模型缩尺效应学术会讨论文集,长江科学院,1991.4