Kabushiki Kaisha Toshiba

Sakae Kawasaki

Hiroshi Kawakami

Daisuke Nomura

Akihiro Onoda

Atsushi Inoue

Kenichi Imai

Kentaro Tani

Kenichi Okuno

Tomohiko Tsukuda

Junichi Tominaga

Tadashi Tanuma

In a turbine rotor blade assembly, a length hin the radial direction of a bucket dovetailof a notch bladeis configured to be shorter than a length hin the radial direction of an effective blade portionof a adjacent notch bladeand a length hin the radial direction of the bucket dovetail. Thus, during an insertion of the notch bladein the axial direction, the rotational movement Rf around the radial direction and the circumferential movement of the notch bladecan be secured.

Turbine rotor blade assembly and steam turbine

An axial flow turbine stage structure has: an annular diaphragm inner ring; an annular diaphragm outer ring arranged radially outside and coaxially with the diaphragm inner ring and separated from the diaphragm inner ring by an annular flow path interposed between them; stationary blades arranged peripherally at intervals in the annular flow path and rigidly secured to the diaphragm inner ring and the diaphragm outer ring; and moving blades rigidly secured to the outer periphery of a rotatable rotor and arranged peripherally at intervals respectively at axially downstream sides of the stationary blades. Through holes are formed in the diaphragm outer ring so as to allow axial upstream side and axially downstream side of the stationary blades to communicate with each other.

Axial flow turbine and stage structure thereof

An axial flow turbine provided with a stage composed of a turbine nozzle and a turbine rotor blade arranged in an axial flow direction. Both end portions of a nozzle blade of the turbine nozzle are supported by a diaphragm inner ring and a diaphragm outer ring, and a flow passage is formed to have its diameter expanded from an upstream stage to a downstream stage. In such axial flow turbine, trailing edges at ends of the nozzle blade supported by the diaphragm inner ring and the diaphragm outer ring are curved as a curvature to an outlet side, and an intermediate portion between the trailing edges is formed to be straight.

Axial flow turbine

In the axial turbine according to the present invention, a nozzle bladeand/or a movable bladehas a profile in which a throat-pitch ratio 's/t' is maximized at a blade-central portion in height, wherein 's' being a shortest distance between a rear edge of a nozzle blade (movable blade) and a back side of another nozzle blade that is adjacent to the nozzle blade, and &#x201c;t&#x201d; being a pitch of the nozzle blades disposed in the row, minimized in a position between the blade-central portion in height and a blade-root portion and increased from a minimized value to the blade-root portion. This structure enables to provide the axial turbine, which permits to control flow distribution of the working fluid in the height direction of the blade in the passage between the blades of a turbine nozzle unit and a turbine movable nozzle and reduce the blade profile loss and the secondary flow loss at the blade-root portion, thus making a further improvement in the turbine stage efficiency.

An object of the present invention is to reduce the adverse effect of interference between stationary blades and moving blades on the performance of an axial-flow turbine and to provide a high-performance turbine stage. Each of the stationary blades has a trailing edge convex toward a face side with respect to a radial line radially extending from the axis of the rotor shaft, and the each of the moving blades has a blade center-of-gravity line convex toward the face side with respect to a radial line radially extending from the axis of the rotor shaft, and shapes of the stationary blades and the moving blades meet conditions expressed by:1&#x3c;&#x3b8;/&#x3b8;1&#x3c;&#x3b8;/&#x3b8; where, &#x3b8;and &#x3b8;are angles between the stationary blade tip and the stationary blade root, and radial lines, and &#x3b8;and &#x3b8;are angles between the blade center-of-gravity line of the moving blade at the tip of the same, and the blade center-of-gravity line of the moving blade at the tip of the moving blade, and radial lines.

Three-dimensional axial-flow turbine stage

A blade for an axial fluid machine comprises an effective blade portion having a root portion and a tip portion and projecting blade portions. The projecting blade portions are defined by axis reference lines extending to an upstream side with respect to a fluid flow from at least one of the root portion and the tip portion of the effective blade portion and by axes obliquely extending from ends of the axis reference lines toward a leading edge of the effective blade portion. The projecting blade portions are formed continuously to and integrally with the leading edge of the effective blade portion so that the effective blade portion and the projecting blade portions have substantially the same maximum blade thickness.

Growing community of inventors

Yokohama, Japan

Sakae Kawasaki