Mitsubishi Heavy Industries Limited

Hisato Arimura

Yasuoki Tomita

Kiyoshi Suenaga

Hideaki Sugishita

Shigemi Mandai

Tatsuo Ishiguro

Sunao Aoki

Shunsuke Torii

Yukihiro Hashimoto

Eiji Akita

Yutaka Kawata

Jun Kubota

Yoshiaki Tsukuda

Naoyuki Seki

Akihiko Shirota

A gas turbine combustor has homogenous air inflow by elimination of turbulence from the air, reducing combustion instability. A combustor has, at its center, a pilot nozzle and eight main nozzles around the pilot nozzle . The air flows in around the individual nozzles and to the leading end of the combustor so that it is used for combustion. An annular flow ring , having a semicirculat section, is disposed at the upstream end portion of a combustion cylinder , and a porous plate and a surrounding rib are disposed downstream of the flow ring . The air inflow is smoothly turned at first by the flow ring and then straightened by the porous plate so that the air flows without any disturbance around the individual nozzles and to the leading end, thereby reducing combustion instability.

Gas turbine and gas turbine combustor

A split ring is disposed on an inner wall of a gas turbine casing. The split ring is composed of a plurality of split segments that are arranged on the inner wall of the casing in circumferential direction. A predetermined clearance is formed between the inner face of a split segment and the rotor blade tips. The split segments are arranged so that a predetermined circumferential clearance is formed between the split segments in order to allow the thermal expansion of the segments. A circumferential end face located upstream side of the segments with respect to the direction of the rotor blade rotation is connected to the inner face by a transition face having a surface formed as an inclined plane. The inclined plane prevents the swirl flow caused by the rotating rotor blade from impinging the upstream end face and, thereby, suppresses a temperature rise of the split segment at the upstream end face.

Split ring for gas turbine 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

Gas turbine starting method is improved to start operation with bleed valves being first throttled, then fully opened on the way and then fully closed at 90% speed, thereby fluid unstableness phenomenon is suppressed and starter motor power is reduced. While inlet guide vane (,) and variable stator vanes (C,to C,) are set to predetermined opening from starting to rated speed, bleed valves (,) are set to predetermined opening until 52% speed for the bleed valve (,) and until 51% speed each for the bleed valves (,), then the bleed valves (,) are fully opened until the speed exceeds 90%, when they are fully closed for rated operation. In the prior art, starting operation is done with bleed valves being first fully opened until the speed is elevated to 90% and then fully closed, but in the present invention, air discharged into ambient air in vain can be reduced and thereby starter motor power can be also reduced.

Gas turbine starting method

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Takasago, Japan

Hisato Arimura