S形复合管道周期流动的数值研究

Numerical analysis of periodic flow in S-shaped composite pipes

采用贴体坐标系下的SIMPLE方法研究了S形复合管道中三维周期性充分发展的层流流动.对流项采用一阶迎风格式和QUICK格式相结合的方法,保证了解的收敛性和高精度特性.数值实验表明,在一个流动周期内,S形复合管道中前后两个半圆弧段中的流动结构一致,但二次流旋转方向和轴向速度的偏移方向相反.曲率对流动有很大的影响,曲率越大轴向速度的最大值越小,二次流的最大值越大.在前后半个周期开始阶段,二次流都有一个突然变小和改变旋转方向的过程.流动阻力随着曲率的增大而增大.

The three dimensional periodic fully developed laminar flow in S-shaped composite pipes was studied using semi-implicit method for pressure linked equations （SIMPLE） scheme in the body-fitted coordinate system. To ensure the convergence and accuracy of the results, first upwind scheme and quadratic upstream interpolation for convective kinematis（QUICK） scheme were combined to discretize the convective terms. Numerical results showed that the flow structures of the former half and latter half are the same in one periodicity. However, the rotation direction of secondary flow and the departure of axial velocity are opposite. Curvature has great influence on the flow： the maximum axial velocity decreases as curvature increases and the maximum secondary flow behaves oppositely. At the beginning of the former half and latter half of the periodicity, the magnitude of secondary flow decreases sharply and the rotation direction changes suddenly. The flow resistance increases with the increase of curvature.