Erosion control through reduction of moisture transport by secondary flow

Abstract

A steam turbine including a plurality of rows of rotating blades interspersed with a plurality of rows of stationary blades incorporates a water barrier extending substantially across a suction side of each blade of at least one of the rows of stationary blades. Each of the water barriers is positioned relatively near a radially outer end of a respective blade and approximately parallel to an end wall of the steam turbine. Moisture which accumulates on the radially outer end of the stationary blades is trapped between the end of the blade and the water barrier. Any water which attempts to flow over the top of the barrier is picked up by the steam flow and broken into small droplets while being rapidly accelerated. Water held behind the barrier and which flows off the trailing edge of the stationary blade only impacts a limited extent of the following rotating blade row. Water collection schemes may be utilized to collect the moisture trapped above the barrier and transfer the moisture through the turbine end wall to appropriate feedwater reheaters.