机械

为了研究90°矩形弯管在不同曲度下的内部流场情况,以Gambit构建管道模型,使用Fluent软件、采用Standardk-ε模型对R/a=1.05～4.55曲度范围内的矩形管内空气的流动进行了数值模拟计算,分析了管内静压强和速度分布、漩涡产生的部位及强度、局部损失系数以及管道弯曲部分的受力情况,探究了弯管后二次流的持续发展情况以及增加导流板对减小局部损失系数的作用。研究结果表明:随着弯管曲度的增大,进口截面压强下降,局部损失系数降低,流体对弯管的作用力增加,弯管后二次流的影响范围增大;增设导流板后,管内压强和速度分布更为均匀,二次流强度减弱,局部损失大大减小。

In order to study the internal flow field of 90? rectangular bends under different curvatures, pipeline models are constructed with Gambit software, and the numerical simulation of the air flow in rectangular bends under different curvatures(R/a=1.05～4.55) is conducted by using Fluent software and the Standard k-epsilon model air flow in rectangular bends under different curvatures(R/a=1.05～4.55). The static pressure and velocity distribution in the pipe, the location and strength of the vortex, the local loss coefficient of the pipe under different curvatures and the stress condition of the bent part of the pipe are analyzed. And the development of the secondary flow after the bend and the effect of installing guide vanes to reduce the local loss coefficient are investigated as well. The results show that as the curvature of the bend increases, the pressure of the inlet section decreases, the local loss coefficient decreases, the fluid force on the bend increases, and the influence range of the secondary flow after the bend increases; after installing the guide vanes, the pressure distribution and the velocity distribution in the pipes become more uniform, the secondary flow is weaker, and the local loss coefficient is greatly reduced.