中文摘要：

应用FLUENT软件及其二次开发技术，采用双流体模型及混合k—ε湍流模型对带有掺气挑坎的陡槽高速掺气水流进行了二维数值模拟。根据掺气水流的特点，重点对相间阻力模型进行了改进，特别在构建相间阻力本构关系式时考虑了湍流扩散的影响。计算结果表明，在相间阻力模型中考虑湍流扩散的影响，可明显改善以往数值计算对水流掺气估算偏低的状况，使掺气浓度的分布和掺气量的计算结果与试验数据符合更加良好，说明湍流扩散对掺气浓度的分布有重要作用。当采用双流体模型模拟掺气水流时，相间作用力模型应考虑湍流扩散的影响。

英文摘要：

The software FLUENT and its secondary developed interface technology were applied to carry out the numerical simulation of the aerated flow downstream of a ramp type aerator in open channel. The two-fluid model and mixture k - ε turbulence model were adopted to describe the water-air two-phase turbulent flow. The turbulence diffusion effect was taken into account in establishing the constitutive equation of drag force. The calculation results show that by this improvement the simulation of air concentration distribution is greatly improved and the calculated magnitude of air entrainment is more closed to the model test data. This result indicates that turbulence diffusion plays an important role in distribution of air concentrations, its effect should be considered in the drag force equation when two-fluid model is adopted to simulate the aerated flow.