基于两相流模式的水流挟沙力研究

Study on sediment transport capacity based on two phase flow theory

水流挟沙力是泥沙研究中一个重要课题,是指在一定水流和边界条件下单位水体能够输移的饱和含沙量。当水流挟带的泥沙量与挟沙能力匹配时,河床不冲不淤;当水流挟带泥沙量与挟沙能力不匹配时,水中泥沙将与河床泥沙发生动态交换,床面淤积或冲刷,对河流床面高程产生影响。作者从考虑悬移质含沙浓度的水沙两相流基本方程出发,导出两相流瞬时能量方程并由此建立新型水流挟沙力公式,收集水流挟沙力水槽试验资料对公式中的系数进行率定。采用另外一些水槽试验资料及河流观测资料对所推求挟沙力公式进行验证,结果表明本文建立的水流挟沙力公式对低含沙水流有较高的适用性。

Sediment transport capacity is defined as the balance amount of suspended load in per unit water on certain flowing and boundary conditions.Suspended load will exchange with sediment on the bed when sediment transport capacity is not equal to the amount of suspended load in water.This will lead to scour or deposition phenomenon.Based on the water-sediment equation of two phase flow,the energy-balance equation and expression of sediment volume concentration have been set up.The parameter A in the sediment volume concentration is calibrated by data of flume experiments.Finally,the formula of sediment concentration is tested by data of other flume experiments and rivers.Verification results show that the expression has a good applicability to low-sediment concentration flow.