涡流管内三维强旋转流场数值模拟与分析

Numerical simulation and analyze of three-dimensional strong swirl flow in the vortex tube

涡流管内可压缩气体的强旋转流动是涡流管能量分离的根本原因和驱动力,因而涡流管内流场研究是揭示涡流管能量分离物理机制的首要关键问题。由于涡流管内可压缩气体的三维强旋转湍流流动,实验测量中存在诸多问题,而CFD数值模拟技术对此具有很大的优势。文中以涡流管内部流场为研究对象,建立了涡流管计算域模型并进行网格划分,讨论了边界条件、湍流模型以及线性方程组求解策略等问题,对不同冷气流率下的涡流管内三维强旋流流场结构特性进行数值模拟,获得了不同冷气流率下的旋转运动、轴向运动、径向运动和循环流的分布特性。研究表明Realizableκ-ε湍流模型能够充分反映强旋流动特点,数值模拟结果与文献中实验值基本吻合。

The compressible flow in the vortex tube is the causation and motivity of the energy separating, so the research on the flow field is the key to investigation the mechanism of energy separating. The three dimensional strong swirl flow is a challenge to the traditional measurement, while the CFD numerical simulation provides a new way. In this paper the flow field is researched by CFD code, the numerical model of vortex tube is built and grids are generated, the boundary conditions, turbulence model and solving scheme are optimized. With the theoretical analyze, the full map of flow field is achieved, and the characters of swirl velocity, axial velocity, radial velocity and secondary flow are showed in detail. The results show that the Realizable k -ε model is suitable to the turbulence flow with strong swirl, and non - dimensional numerical results are in satisfactory agreements with the other＇s experimental data.