层流泡状流双流体模型的积分解法

为弥补用于泡状流双流体模型的直接离散差分解法无法比较直观地揭示流场成因的缺陷,针对最基本的泡状流(垂直圆管内充分发展段层流泡状流)提出了一种双流体模型解法——积分解法。首先通过对双流体模型进行符号积分,得到表示该模型的近似解析解,然后再用数值方法迭代求得数值解。该积分解法得到的近似解析解比较直观地表明:液相轴向速度主要与阻力、浮力和空泡率有关,而空泡率则主要受升力和壁面力的影响。数值解与实验数据基本吻合,预测精度一般不低于75%。

Integrated two-fluid model for laminar bubbly flow

An integrated two-fluid model for basic bubbly flows was used to analyze fully developed laminar bubbly flows in vertical pipes. The algorithm overcomes the limitations of the direct discrete difference method, which cannot directly show the reasons for the flow field development. An approximate analytical solution of the two-fluid model was first developed using symbolic integration of the two-fluid model, with the numerical solution then obtained by numerical iterations of the approximate analytical solution. The resulting solution shows that the liquid axial velocity is mainly affected by the drag force, buoyancy force and volume fraction, and that the volume fraction is mainly influenced by the lift force and the wall drag. The numerical solution coincides reasonably well with experimental data with a prediction accuracy of at least 75%.