OPTICAL MEASUREMENT OF WET STEAM IN TURBINES

The wetness fraction of steam causes dangerous erosion of turbine blad es and other components, and decreases efficiency of stages. The instr umentation of wet steam has, therefore, attracted growing interest fro m the point of safety and economical operation of power stations. Base d on the light scattering technique, a method is presented that is cap able of measuring the wetness fraction of steam, the mean water drople t diameter as well as their full size distribution. An optical probe h as been constructed that can be used in the turbines in operation. Its main characteristic and features are discussed in this paper. Experim ental results in a 200 MW condensing steam turbine are also given.