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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。
By using FLUENT software and Realizable κ-ε turbulence model, the three-dimensional numerical simulation of 90 ° -costatic tunnel with different Reynolds numbers on the horizontal plane was carried out. The curves of turbulence with Reynolds number of 2 × 104 ~ 2 × 107 Of the second flow, kinetic energy correction coefficient changes with the Reynolds number changes, and gives the secondary flow development, the distribution of flow velocity to determine the basis. The results show that although the Reynolds number is the main influence factor of the secondary flow strength, the Reynolds number located in this area has no obvious effect on the secondary flow. The larger the Reynolds number is, the worse the water flow is and the more disturbance the kinetic energy On the contrary, the smaller the coefficient is, the more uniform the cross-sectional flow velocity distribution. The secondary flow can remarkably reduce the coefficient of kinetic energy correction, and the smaller the Reynolds number is, the greater the reduction effect. The differential pressure coefficient can be used as a basis for judging the development of secondary flow ; The ratio of the peak value of flow velocity to the average value of flow velocity can be used as the basis for judging the uniformity of the flow velocity distribution of the tunnel-shaped section. The larger the Reynolds number is, the better the applicability is.