Abstract: A rotor blade includes a blade portion that extends in a spanwise direction from a hub portion to a tip portion and has a pressure-side surface and a suction-side surface, a blade portion is formed by profiles with airfoil shapes stacked in the spanwise direction, and a stacking line connecting gravity centers of the profiles at each spanwise position is a straight line parallel to a radial direction at a part from the hub portion to an outer end of a secondary flow region in a vicinity of the hub portion, and is a curved line, along which a distance measured from the straight line parallel to the radial direction toward a side of the suction-side surface gradually increases toward the tip portion, at a part from the outer end of the secondary flow region to the tip portion.

Abstract: Provided is a rotor blade of an axial-flow fluid machine capable of maintaining an effect of reducing a bending stress acting on a blade portion and reducing a secondary flow loss in the vicinity of a hub-side end wall. A rotor blade includes a blade portion that extends in a spanwise direction from a hub portion to a tip portion and has a pressure-side surface and a suction-side surface, a blade portion is formed by profiles with airfoil shapes stacked in the spanwise direction, and a stacking line connecting gravity centers of the profiles at each spanwise position is a straight line parallel to a radial direction at a part from the hub portion to an outer end of a secondary flow region in a vicinity of the hub portion, and is a curved line, along which a distance measured from the straight line parallel to the radial direction toward a side of the suction-side surface gradually increases toward the tip portion, at a part from the outer end of the secondary flow region to the tip portion.