Patent ID: 6375420
Filing Date: 2002-04-23
Classification: F01D,Y10S

Abstract:
In a turbine moving blade assembly for a steam turbine which has a plurality of stages each provided with turbine moving blades attached to a turbine shaft and fixed turbine nozzle blades positioned axially adjacent the turbine moving blades, the turbine moving blades being circumferentially spaced with adjacent turbine moving blades being interconnected intermediate their ends and also at their radially outer tips, each of the turbine moving blades being twisted from the blade root to the blade tip, the improvement wherein the twist angles at blade cross-sections along the height of each turbine moving blade are differentially twisted to produce a distribution of throatÂ·pitch ratio (S/T) along the turbine moving blade height direction from the blade root to the blade tip that follows a curve having at least one minimum and one maximum, wherein said minimum is located in the turbine moving blade height range of about 10% to about 20%, and the maximum is located in the turbine moving blade height range of about 25% to about 35%.