Mitsubishi Heavy Industries Limited

Mitsubishi Hitachi Power Systems, Ltd.

Yukihiro Hashimoto

Motoki Kato

Yasuoki Tomita

Kiyoshi Suenaga

Hiroki Fukuno

Sunao Aoki

Kazuharu Hirokawa

Rintaro Chikami

Masahito Kataoka

Hiroji Tada

Shigeyuki Maeda

Hironobu Hakoda

Takashi Nakano

Hiroshi Ishikawa

Katsunori Tanaka

Shinya Hashimoto

Shin Nishimoto

Hidekazu Uehara

Tatsuo Ishiguro

Eisaku Ito

Kazuo Uematsu

Tanehiro Shinohara

Yoichi Iwasaki

Taiji Torigoe

Koji Takahashi

Shunsuke Torii

Keita Takamura

Keizo Tsukagoshi

Koichi Akagi

Kouichi Akagi

Ichiro Fukue

Ryuichi Yamamoto

Masato Araki

Kunihiro Morishita

Mitsuru Kondo

Masao Terazaki

Jun Kubota

Toshishige Ai

Hisato Arimura

Toshiaki Sano

Keisuke Ihara

Masahiko Mori

Kei Osawa

Hiroshi Shimizu

Akihiko Shirota

Norikazu Tezuka

Sousuke Nakamura

Hiroshi Katsuura

Jyunichiro Masada

Nobuyuki Izutsu

A structure for a gas turbine casing, capable of preventing gas from leaking when the structure is subjected to pressure. A structure for a gas turbine casing, divided by a horizontal plane at flange sections into two halves comprising an upper-half casing () and a lower-half casing (). The structure is provided with bolts () which are disposed in the inner surfaces of the upper-half casing () and the lower-half casing () so as to bridge therebetween, upper nuts () which are disposed in the inner surface of the upper-half casing () and attached to the bolts (), and lower nuts () which are disposed in the inner surface of the lower-half casing () and attached to the bolts ().

Structure for gas turbine casing

A shaft sealing device is provided in an annular space between a rotor and a stator surrounding an outer periphery of the rotor, and divides the annular space in the direction of an axis of the rotor into a high-pressure region and a low-pressure region. The shaft sealing device includes a seal body obtained by stacking a plurality of thin plate sealing pieces in a circumferential direction of the rotor; and a high-pressure side plate that extends from the stator toward the radial inner side so as to run along the high-pressure side of the seal body, and is segmented into a plurality of portions in the circumferential direction, and includes a rigidity imparting member configured to impart rigidity in the direction of the axis to a portion of the surface of the high-pressure side plate that faces the high-pressure region.

Shaft sealing device and rotating machine comprising same

A bolt has a male screw with a surface hardening portion that has an increased surface hardness and that is applied with a compressive residual stress. The male screw is formed by cutting the bolt, and performing a process to provide at least on the surface of the male screw of the bolt the surface hardening portion that has increased hardness and that is applied with a compressive residual stress. As a result, the fatigue resistance of the male screw is improved and the bolt is effective for use in a portion where the male screw is subject to a repetitive stress.

Bolt and manufacturing method of bolt

The present invention provides a hollow structure with at least one flange which can eliminate the possibility of creating crackings due to the thermal fatigue, thereby improving the durability thereof. A hollow structure with an flange according to the present invention includes at least one annular flange fixedly attached around the hollow structure which has a temperature gradient in the direction of the thickness of the wall thereof, wherein said at least one annular flange including an outer portion formed of a metal material having a coefficient of linear expansion greater than that of the metal material forming another portion of said at least one annular flange.

Hollow structure with flange

Cooling air passages are formed in the wall of an exhaust casing connected to a turbine casing of a gas turbine. Low pressure air extracted from the low pressure stage of an air compressor of the gas turbine is supplied to the cooling air passage from the portion near the downstream end of the exhaust casing. Cooling air flows through the cooling air passage toward the upstream end of the exhaust casing and then flows into an annular cavity formed in the turbine casing near the portion corresponding to the last turbine stage. Therefore, the metal temperature of the exhaust casing near the upstream end (near the joint between the exhaust casing and the turbine casing) is lowered by the cooling air and, as cooling air of a relatively high temperature is supplied to the cavity in the turbine casing, the metal temperature of the turbine casing near the downstream end becomes higher than that provided by a conventional cooling system. Therefore, the difference between the metal temperatures of the turbine casing and the exhaust casing becomes very small and the thermal stress exerted on the exhaust casing due to the temperature difference can be largely reduced.

Air-cooled gas turbine exhaust casing

A gas turbine moving blade is provided which prevents occurrence of cracks caused by thermal stresses due to temperature differences between a blade and a platform while the gas turbine is being stopped. During steady operation time of the moving blade, cooling air enters cooling passages to flow through other cooling passages for cooling the blade, and then to flow out of the blade. A recessed portion having a smooth curved surface is provided in the platform near a blade fitting portion on the blade trailing edge side. A fillet of the blade fitting portion on the blade trailing edge side has a curved surface with curvature larger than that of a conventional blade fitting portion. A hub slot below the fillet, for blowing air, has a cross sectional area larger than other slots of the blade trailing edge. A thermal barrier coating is applied to the blade surface. By the above construction, thermal stresses due to temperature differences between the blade and the platform during gas turbine stoppage are made smaller and occurrence of cracks is prevented.

Gas turbine moving blade

The present invention provides a stationary blade of integrated segment construction, in which a thermal barrier coating can be applied to the whole blade surface and excessive stress can be avoided in a shroud. A plate seat connector is provided at each end face portion of an inside shroud and an outside shroud attached to outside and inside ends of gas turbine stationary blade. Several stationary blades are integrated by joining the plate seat connectors of the adjacent shrouds by means of bolts and nuts to provide a stationary blade of integrated segment construction.

Stationary blade of integrated segment construction and manufacturing method therefor

Stress occurring in a moving blade in a gas turbine stopping process is decreased. Time t,is load decrease start or fuel throttling start, time t,is no load operation start, time t,is fuel shut-off and time t,is a time of largest stress. A 4/4 load maintained until t,decreases gradually to a 0/4 load at t,, which is then maintained until t,and then decreases further. The rotational speed is the rated speed until t,, at which point it is controlled to be decreased gradually to about 60% of the rated rotational speed at t,. The metal differential temperature between a moving blade point A and a platform point B is constant until t,and is then decreased slightly between t,and t,and between t,and t,. Differential temperature &Dgr;t, largest after t,, occurs at t,. Stress occurring in the moving blade, while decreasing between t,and t,, becomes largest at t,by the effect of centrifugal force and thermal stress, but as the rotational speed is decreased to about 60% of the rated rotational speed at t,and the metal temperature is also decreased as compared with the prior art, the influence of the centrifugal force and the differential temperature is decreased, whereby stress occurring in the moving blade is mitigated.

Revolution speed control method in gas turbine shutdown process

A number of air-transpiration holes (,) are provided at a leading edge portion (,) of a cooled blade (,). Cooling air flowing through a cooling air passage (,) formed inside of the blade blows out to the blade surface of the leading edge portion (,) of the cooled blade (,) by way of the air-transpiration holes (,), to thereby shower-head cool the surface of the leading edge portion (,). The air-transpiration holes (,) are formed so as to extend substantially orthogonal to the leading edge surface of the cooled blade (,) such that the acute-angled portions are eliminated, whereby thermal stress is reduced and cracking is prevented.

Gas turbine cooling blade

A cooled moving blade for a gas turbine which has a blade profile capable of more effectively reducing thermal stress in a blade base portion and, thus, preventing cracks from occurring. A moving blade (,) is fixedly secured to a platform (,). On the other hand, a cooling air passage (,) is formed in a serpentine pattern inside of the blade for cooling with cooling air. The moving blade (,) has a base portion of a profile formed by an elliptically curved surface (,) and a rectilinear surface portion (,), wherein the rectilinear surface portion (,) is provided at a hub portion of the blade where thermal stress is large. The cross-sectional area of the blade is increased by providing the rectilinear surface portion (,) The heat capacity is increased, compared with the conventional blade, due to the increased cross-sectional area of the blade. This, in turn, results in a decrease of the temperature difference due to the thermal stress. Thus, the thermal stress can be suppressed more effectively than with the conventional blade.

Cooled moving blade for gas turbine

A gas turbine seal structure provided between end portions of a moving blade platform and a stationary blade inside shroud. The sealing performance of the seal structure is improved by increasing the resistance to the flow of air. A seal plate (,) is mounted to an end portion of a platform (,) of the moving blade (,) and a seal portion is formed by seal fins (,) and a honeycomb seal (,) disposed on a lower surface of an end portion (,) of an inside shroud (,) of a stationary blade (,). Sealing air from the stationary blade (,) produces a high temperature in a cavity (,) and flows into a space (,), and also air leaking from the cooling air of the moving blade (,) is able to escape into a high temperature combustion gas passage through a seal portion. However, since the seal plate has three seal fins (,) that are inclined in a direction so as to oppose the air flow, air resistance is increased and the flow of air into the combustion gas passage is prevented.

Gas turbine seal apparatus

Air separator for gas turbines

In the present disclosure, an air pipe extends through a stationary blade between outer and inner shrouds. Further, an air passage is directed to a lower portion of the stationary blade and is communicated with the air pipe so that a serpentine cooling passage is formed. The air enters a cavity from the air passage and is discharged to a gas passage through an air hole, a passage and a seal. Thus, the cavity is sealed at a high pressure. Cooling air is supplied from the air passage to a rotating blade through a cooling air hole, a cooling air chamber, a radial hole and a lower portion of a platform. The stationary blade is cooled by the air through the air passage. The cooling air can be supplied to the rotating blade at a low temperature and a high pressure as they are. Accordingly, the air can be also supplied to the rotating blade when a rotor is cooled by vapor.

Blade cooling air supplying system of gas turbine

A gas turbine stationary blade unit in which two stationary blades are formed in a single segment by divided shrouds functions to lessen the occurrence of cracks. Two stationary blades 1a, 1b are fixed to an outer shroud and an inner shroud, respectively. Each shroud is divided into two sections 2a, 2b and 3a, 3b. Flanges 4a, 4b are provided to connect the section together by bolts via boltholes 7. Likewise, flanges 5a, 5b are provided to form a similar connection or joint. If the two stationary blades 1a, 1b are fixed in a single segment by the shrouds which are not divided, a restraining force becomes larger, local stress occurs due to thermal stress and the frequency of crack occurrence increases. However, since the shrouds are divided respectively into two parts and jointed together by bolts, the crack occurrence is lessened. Also, pinholes are provided in opposing faces at the divided portion of the shrouds. Also, pins are inserted into the pinholes for connection of the divided shrouds, thereby relative movement between the divided shrouds is prevented and a strong jointed blade unit is provided.

Gas turbine stationary blade unit

A gas turbine moving blade steam cooling system in which leakage of steam for cooling a moving blade is prevented and thermal stress at a blade root end portion is mitigated. Each end portion of a blade root portion (3) of the moving blade (1) is projected so as to form a projection portions (4a, 4b). A steam passage 5 is provided between the projection portions (4a, 4b) and a steam supply port 5a and a steam recovery port (5b) are provided downwardly with the respect to the steam passage 5. The steam supply port (5a) connects to a steam supply passage (20) and the steam recovery port (5b) connects to a steam recovery passage (21). Steam is supplied from the steam supply port (5a) into a blade interior and is recovered through the steam recovery port (5b). Side surface seal plates (6, 7 and 8) are provided for preventing steam leakage. The steam cools the moving blade (1) and can be recovered without leakage and stress concentration due to heat at the projection portions (4a, 4b) of the blade root end portion.

Gas turbine moving blade steam cooling system

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Takasago, Japan

Yukihiro Hashimoto