汽轮机静叶栅中水滴运动与沉积规律的数值研究

Numerical Investigation of Movement and Deposition of Water Droplets on Steam Turbine Stator Cascade

在FLUENT计算流体力学软件中应用RNGk-ε湍流模型、近壁面双层区模型和拉格朗日法对某300MW汽轮机末级静叶水滴沉积进行了数值模拟。结果表明：大水滴不能完全跟随流线运动，运动轨迹偏向叶片压力面；直径小于1μm的水滴以湍流扩散的方式沉积在叶片表面上，直径为1～5μm的水滴在湍流扩散和惯性的综合作用下沉积，直径大于5μm的水滴的沉积受到湍流扩散作用的影响很小，主要在惯性作用下沉积；直径小于1.6μm的水滴主要沉积在静叶的压力面上靠近尾缘的一小段区域和吸力面上靠近尾缘的一大段区域，直径大于1.6μm的水滴主要沉积在压力面尾缘附近和吸力面前缘处。研究水滴沉积分布对于设计静叶去湿和减少动叶侵蚀具有参考作用。

The numerical simulation of deposition of water droplets on the stator blades of the final stage of a 300 MW steam turbine was performed with FLUENT using RNG k-ε turbulence model, the two-layer zonal near-wall model and the Lagrangian method. The results show that the coarse water droplets fail to follow the vapor streamline exactly and lean towards the pressure side of the blade. The water droplet deposits on the blade surface for a diameter of less than 1μm by turbulent diffusion, for 1-5μm, by combination of turbulent diffusion and inertia, and for larger than 5μm, by inertia mostly. The water droplet less than 1.6μm in diameter deposits in the small area of the pressure side and in the large area of the suction side near the trailing. The others deposit in the area of the pressure side near the trailing and in the area of the suction side near the leading.