Experimental studies of polydispersed wet steam flows in a turbine blade cascade

The paper describes experimental studies of water droplet motion in turbine cascades using laser diagnostic techniques (particle image velocimetry/particle tracking velocimetry). The investigations were performed at the experimental installation Wet Steam Circuit – 2 (WSC-2) at the Moscow Power Engineering Institute. The facility allows the study of the flow of superheated, saturated and wet steam over a broad range of velocities. The effect of the steam initial conditions on the behaviour of the coarse droplets downstream of a nozzle blade cascade has been studied for subsonic and supersonic flow. The variation of the average droplet velocities and angles across the blade pitch, and the droplet trajectories have been obtained. The relationship between the slip coefficients of droplets having minimal velocities in the blade trailing-edge plane, the initial steam wetness, and the axial distance downstream of the nozzle blade are suggested as the criteria characterising the coarse droplet motion downstream of the cascade.