针对蜗壳(包括固定导叶)内流场的回流和撞击问题,以Fluent为工具,采用SIMPLE算法,对低水头电站蜗壳和导水机构进行三维不可压定常粘性流动数值模拟,分析了产生问题的原因,提出采用改善固定导叶型线及进出口角度的方法对固定导叶进行优化。对优化后模型进行最优工况下的数值计算表明,优化结果较为理想,改善了原设计中部分导叶处流态不稳定的状况,为水轮机固定导叶的优化提供了依据。 Aiming at the problem of backflow and impact of the flow field in the volute (including the fixed vane), the numerical simulation of three-dimensional incompressible constant viscous flow was carried out using the Fluent tool and the SIMPLE algorithm. The reason of the problem is proposed to improve the fixed guide vane by adopting the method of improving the fixed guide vane line and the angle of import and export. The numerical calculation of the optimized model under the optimal operating conditions shows that the optimization result is ideal, which improves the instability of the flow regime at some guide vanes in the original design and provides the basis for the optimization of the turbine guide vane.