摘要
利用FLUENT软件并结合Realizableκ-ε湍流模型,对不同雷诺数下水平面上的90°有压城门洞形弯道进行三维数值模拟,研究了雷诺数为2×104~2×107的湍流区弯道内的二次流、动能修正系数随雷诺数改变的变化规律,并给出了二次流发展情况、流速分布均匀性的判断依据。结果表明,虽然雷诺数为二次流强度的主要影响因子,但位于该区内的雷诺数对二次流并无明显影响;雷诺数越大,水流混掺加剧致使水流越紊乱,而动能修正系数反而越小,断面流速分布越均匀;二次流能显著地削减动能修正系数值,且雷诺数越小,这种削减作用越大;压差系数可作为判断二次流的发展状况的依据;流速峰值与流速平均值的比值可作为判断城门洞形断面流速分布的均匀性的依据,且雷诺数越大,适用性越好。
The three-dimensional flow under different Reynolds number in 90°city gate-shaped bend tunnel was simulated numerically by the Realizableκ-εturbulent model in software FLUENT.And the law about the secondary flow and the kinetic energy correction factor changing with the Reynolds number in the range of 2×104 to 2×107 was analyzed.Then the judgment of secondary flow development and velocity distribution uniformity was given.The results show that although the Reynolds number is the main factor influencing the intensity of secondary flow,but it has no obvious impact on the secondary flow in the turbulent zone.The larger the Reynolds number is,the smaller the kinetic energy factor is,the more disorder the flow caused by mixed water,the more even the section velocity distribution is.The secondary flow can reduce the kinetic energy correction factor observably,and the bigger the Reynolds number is,the greater the cutting effect is.The differential pressure coefficient is suitable for the development of secondary flow.The ratio of maximum velocity and average velocity applies to judge sectional velocity distribution uniformity,and the bigger the Reynolds number is,the better applicability is.
出处
《水电能源科学》
北大核心
2016年第5期102-106,101,共6页
Water Resources and Power
基金
国家自然科学基金项目(90610027
51079051)
关键词
城门洞形断面
雷诺数
二次流
动能修正系数
流速峰值
city gate-shaped section
Reynolds number
secondary flow
kinetic energy correction factor
maximum velocity
