Patent ID: 11959394
Assignee: MITSUBISHI ELECTRIC CORPORATION
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F | IPC F

Claim 7:
8. A turbine rotor blade, comprising:
an airfoil portion having a pressure surface and a suction surface;
a platform portion formed on a base end side of the airfoil portion;
a shank portion formed opposite to the airfoil portion across the platform portion; and
at least a suction side fillet portion of a fillet portion formed in a connection between the suction surface and an upper surface of the platform portion,
wherein the suction side fillet portion includes:
a central fillet portion which is formed at a position including a center of a length of the suction side fillet portion along an extension direction of the suction side fillet portion;
an upstream intermediate fillet portion which is located between the central fillet portion and a front edge that is an upstream end of the suction side fillet portion, and in which a fillet height of the upstream intermediate fillet portion from the upper surface of the platform portion is higher than a fillet height of the central fillet portion; and
a downstream intermediate fillet portion which is located between the central fillet portion and a rear edge that is a downstream end of the suction side fillet portion, and in which a fillet height of the downstream intermediate fillet portion from the upper surface of the platform portion is higher than the fillet height of the central fillet portion,

wherein the central fillet portion of the suction side fillet portion has a first cross section demarcated by:
a first curved line connecting the suction surface and an end edge of the upper surface of the platform portion;
a first line segment extending from a position where the first curved line is connected to the suction surface to the upper surface of the platform portion along a blade height direction; and
a second line segment extending from a position where the first line segment is connected to the upper surface of the platform portion to the end edge,

wherein the first curved line is defined by a part of an ellipse,
wherein a center of the ellipse is located opposite to the airfoil portion across the end edge of the platform portion in a blade thickness direction, and
wherein a position of a lower end of the ellipse is located below the end edge of the platform portion in the blade height direction.