中文摘要：

火电厂烟风道系统中广泛应用的90°收缩弯头对流场影响较大。对此,本文借助数值模拟软件Fluent,以90°收缩弯头基础方案为参照,分别对外侧形状为大切角、圆形、外大弧3种弯头的内部流场及其阻力特性进行数值模拟,并通过添加导流板优化90°收缩弯头结构。结果表明,弯头外侧形状为大圆弧时可减小系统阻力,合理设置导流板能有效改善弯头局部阻力。该研究结果可对烟风道系统的优化设计提供指导。

英文摘要：

Being limited by land area and economic cost, the layout of flue gas duct system is generally compact, and numerous special-shaped pieces exist in this system, such as the bend pipe, rectangle-circle connectors and expansion and contraction sections. The fluid resistance in the system mainly includes frictional resistance and local resistance. The former is associated with the boundary layer flow characteristics and the pipe length, it can be reduced by rationally arranging the layout of the pipes. When the fluids flow through these shaped parts, the main factors producing the local resistance are the dramatic changes in the magnitude and direction of velocity, pressure and flow deflection vortex and flow separation. On the basis of the Fluent software, numerical simulation on flow flied and its resistance characteristics near the 90° shrunk bend pipe connector in the flue gas duct was carried out. Moreover, guide plate was installed to optimize the flue duct system, thus to reduce the local resistance in the flue gas duct and further lower the total resistance and increase the power generation economic benefits. The simulation results have a guiding significance to the optimization design of the flue gas ducts.