Controlled reaction L-2R steam turbine blade

Claim 1

A steam turbine comprising: a) a stationary cylinder for containing a steam flow, and a rotor enclosed by said cylinder; b) a stage disposed within said cylinder and having means for at least partially expanding said steam flow, whereby said steam flow undergoes a stage pressure drop as it expands through said stage, said stage having a row of vanes and a row of blades, said row of blades having a tip region and a hub region; c) said row of vanes having means for causing said steam to undergo a first portion of said stage pressure drop as said steam flows through said row of vanes; and d) said row of blades having (i) means for causing said steam to undergo a second portion of said stage pressure drop as said steam flows through said row of blades, and (ii) means for controlling the radial distribution of said second portion of said stage pressure drop so that said second portion is greater than 20% of said stage pressure drop in said hub region and less than 50% of said stage pressure drop in said tip region, e) said pressure drop radial distribution control means comprising(i) each of said blades having an airfoil portion having a base section, a mid-height section, a 25% height section between said base and mid-height sections, a 75% height section between said mid-height section and said tip region, and each of said airfoil portions being defined by the following parameters having approximately the values indicated below, all angles being expressed in degrees: ______________________________________ 75%- Parameter 25% Height Mid-Height Height ______________________________________ Pitch/Chord Ratio 0.6 0.7 0.8 Pitch/Width Ratio 0.7 0.9 1.3 Stagger Angle 25 41 54 Max Thickness/Chord Ratio 0.3 0.2 0.1 Metal Turning Angle 106 84 62 Exit Opening (mm) 21 21 22 Exit Opening Angle 33 31 30 Inlet Metal Angle 55 78 102 Inlet Included Angle 42 51 40 Exit Metal Angle 20 19 17 Suction Surface 16 15 14 Turning Angle ______________________________________