两级动叶可调轴流风机内流特征的数值模拟

Numerical Simulation on Internal Flow Field of a Two-stage Variable Vane Axial Flow Fan

采用Fluent软件对某600MW机组配套的两级动叶可调轴流一次风机进行了全三维定常数值模拟,分析了风机第一、第二级叶轮内流特征和动叶安装角对风机性能的影响.结果表明:第二级叶轮出口总压整体呈现高压区和次高压区交替分布的特征,且比第一级叶轮的对称性差;第一、第二级叶轮叶片压力面、吸力面的总压和静压分布规律相似;第二级叶轮叶片压力面和吸力面相应位置上的静压值均大于第一级叶轮叶片;随着动叶安装角的增大,第一、第二级叶轮的总压升系数和静叶的扩压系数均增大,且第二级叶轮大于第一级叶轮,表明第二级叶轮的做功能力和静叶的扩压能力均比第一级叶轮的大.

Numerical simulation was carried out on steady-state three-dimensional flow field in a two-state variable vane axial flow fan matched for 600 MW units using Fluent software,so as to analyze the internal flow field of its first-stage and second-stage impeller and the influence of installation angle on the performance of axial flow fan.Results show that the total outlet pressure of second-stage impeller distributes alternatively in the way of high-pressure zone and sub-high-pressure zone,presenting lower symmetry than the first-stage impeller.The total and static pressure curves on pressure and suction side of both impellers＇ blades have similar distributions,and the static pressure on blades of second-stage impeller is larger than that in corresponding position of the first-stage impeller on both the pressure and suction surfaces.With the rise of installation angle,the total pressure rise coefficient of both impellers and the diffuser coefficient of the guide vane tend to increase,and the increasing range of coefficient for the second-stage impeller is greater than the first one,showing a superior performance of the second-stage impeller in both working and diffusion capability respectively of the first-stage impeller.