冰盖下冰花浓度分布的数值模拟

封冻河道内的冰花分布规律对冰期水文及环境分析有着重要的意义. 视冰花为连续介质, 基于多相流理论和欧拉-欧拉模型方法, 建立了河渠垂向二维标准k-ε紊流数值模型. 在不同的水流流速、 冰花颗粒尺寸、 上游来冰量条件下, 对冰盖下冰花浓度场进行了模拟分析, 得到了冰盖下冰花分布特征. 结果表明: 水流流速越大, 冰花沿垂向分布范围越大, 冰花浓度分布曲线斜率越大, 冰花浓度沿垂向的均匀性越大, 同时浓度最大值越小; 冰花颗粒尺寸越大, 冰花沿垂向分布范围越大, 冰花浓度分布曲线斜率越大; 上游来冰量越大, 冰花沿垂向分布范围越大, 在同一水深其浓度值也越大, 冰花浓度沿垂向分布的均匀性越大.

Numerical Simulation of Frazil Concentration under Ice Cover

Frazil concentration has important significance for analyzing hydrology and environment under ice cover in period of freezing weather.Based on multiphase flow theory and Euler-Euler Model,frazil granules are treated as pseudo-fluid to establish two-dimensional river k-ε model along flow direction in this paper.Frazil concentration field is simulated and analyzed to obtain the distribution of frazil granules under ice cover for different flow velocities,upstream frazil concentrations and frazil granules sizes.The simulated velocity distribution is agreed with the laboratory measured values,which verifies the reliability of the model.The results show that: The greater the flow velocity,the greater the distribution area of frazil along the vertical direction,the greater the slope of frazil concentration profile,and the smaller of the maximum frazil concentration.The larger the frazil granules size,the greater the distribution area of frazil along the vertical direction and the greater the slope of frazil concentration profile.The greater the upstream frazil input,the greater the frazil distribution area along the vertical direction,the greater the concentration at the same level,and the greater the uniformity of frazil concentration.