US 11,739,648 B2
Steam turbine rotor blade and manufacturing method and remodeling method of steam turbine rotor blade
Yasuhiro Sasao, Tokyo (JP); Soichiro Tabata, Tokyo (JP); Ryo Takata, Tokyo (JP); and Takeshi Kudo, Tokyo (JP)
Assigned to MITSUBISHI HEAVY INDUSTRIES, LTD., Tokyo (JP)
Filed by MITSUBISHI HEAVY INDUSTRIES, LTD., Tokyo (JP)
Filed on Nov. 19, 2021, as Appl. No. 17/531,207.
Claims priority of application No. 2020-195377 (JP), filed on Nov. 25, 2020.
Prior Publication US 2022/0162949 A1, May 26, 2022
Int. Cl. F01D 5/22 (2006.01); F01D 25/32 (2006.01); F01D 5/14 (2006.01); B23P 15/02 (2006.01); B24C 1/10 (2006.01)
CPC F01D 5/22 (2013.01) [F05D 2230/10 (2013.01); F05D 2260/602 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A steam turbine rotor blade having a tie-boss for joining to adjacent blades at an intermediate position in a blade length direction, the steam turbine rotor blade comprising:
an airfoil part in which a blade surface is partly hollow as viewed in a section obtained by cutting the airfoil part with an orthogonal plane to a rotation center line of a turbine and wherein a recessed blade surface forms the hollow partial blade surface and is positioned radially below the tie-boss at least in a region on a pressure side, and wherein the recessed blade surface extends in a strip shape in a blade chord length direction,
wherein
a starting end of the recessed blade surface that extends in the strip shape is located in a suction side surface and a terminal end of the recessed blade surface is located in a pressure side surface,
the recessed blade surface is continuous from the starting end to the terminal end via a blade leading edge and extends such that a distance from a blade root monotonically increases from the starting end to the terminal end, and
on a suction side of the rotor blade, the recessed blade surface is inclined outward in a radial direction toward the leading edge of the rotor blade, and on a pressure side of the rotor blade, the recessed blade surface is inclined outward in the radial direction toward a blade trailing edge.