Numerical Simulation on Wet Steam Flow in the Last Stage of Steam Turbine in Nuclear Power Plant

High-capacity, low inlet parameters and huge flow are the characteristics of the nuclear steam turbine. As a result of adopting saturation steam and long blade, water erosion of last stage blade become more prominent. The secondary droplets´ continuously dynamic impact to the movable vanes in the wake of hollow stationary blade is the main reason for water erosion. So, it is necessary to research wet steam flow, vapor-liquid two phase flow, movement of droplets of different size and volume of sediment. The results of numerical simulation on wet steam two-phase flow in the last stage of nuclear turbine based on FLUENT software can show the flow characteristics of the wet steam. The most effective measure to prevent or mitigate the water erosion is that slotting suction ports in suitable locations of the hollow stationary blades´ concave surface or convex surface. Research shows that, suction slot should be set up in and around the hollow stationary blades, in a relatively wide of the near 0.8.