Fluid reaction surfaces (i.e. – impellers) – With heating – cooling or thermal insulation means – Changing state mass within or fluid flow through working...
Reexamination Certificate
1999-02-18
2001-03-06
Verdier, Christopher (Department: 3745)
Fluid reaction surfaces (i.e., impellers)
With heating, cooling or thermal insulation means
Changing state mass within or fluid flow through working...
Reexamination Certificate
active
06196799
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a gas turbine moving blade platform constructed so as to enhance a cooling performance thereof.
2. Description of the Prior Art
FIG. 8
is a cross sectional view of a representative prior art gas turbine moving blade platform. In
FIG. 8
, numeral
80
designates a platform in its entire form and numeral
51
designates a first stage moving blade. Numeral
52
designates a leading edge passage of the moving blade
51
and cooling passages
83
,
84
are communicated with the leading edge passage
52
and extending toward respective side portions of the platform
80
. The cooling passages
83
,
84
connected to cooling passages
85
,
86
, respectively, on both side portions and the cooling passages
85
,
86
open at a rear end of the platform
80
so that cooling air
70
is blown therefrom, respectively.
Cooling passages
87
and
88
,
89
and
90
are provided in a front portion of the platform
80
, on both sides thereof and the cooling passages
88
to
90
are bored at an angle from a lower surface toward an upper surface of the platform
80
so as to open at the upper surface so that cooling air is blown therefrom. Also, cooling passages
91
,
92
,
93
are bored in a rear portion of the platform
80
so as to extend likewise at an angle from the lower surface toward the upper surface of the platform
80
and to open at the rear end thereof so that the cooling air is blown therefrom.
Further, in a central portion of the platform
80
, there are provided cooling passages
94
,
95
,
96
,
97
,
98
and these cooling passages are also bored at an angle from the lower surface toward the upper surface of the platform
80
so that the cooling air is blown from the upper surface. An outlet end portion of each of the cooling passages
94
to
98
is worked so as to be enlarged in a funnel-like shape so that the cooling air is diffused over the upper surface.
FIG. 9
is a contracted cross sectional view taken on line
9
—
9
of
FIG. 8
, wherein the cooling passages
85
,
86
are provided in both side portions of the platform
80
and the cooling passage
97
is bored at an angle from the lower surface toward the upper surface of the platform
80
.
FIG. 10
is a contracted cross sectional view taken on line
10
—
10
of
FIG. 8
, wherein there are provided the cooling passage
85
extending from the front portion toward the rear portion of the platform
80
so as to open at the rear end, and the cooling passages
87
,
94
to
98
extend angularly so that the cooling air is blown therethrough rearwardly and upwardly, respectively.
In the platform
80
, constructed as above, cooling air which has been supplied into the moving blade
51
through the leading edge passage
52
flows portionally into the cooling passages
85
,
86
for cooling of both side portions of the platform
80
to then flow out of the rear end of the platform
80
. Also, the cooling passages
87
to
90
,
91
to
93
, respectively, are inclined in the front and rear portions of the platform
80
so that cooling air is introduced thereinto from the lower surface of the platform
80
so as to flow out of the upper surface of the front and rear end portions of the platform
80
. Further, the cooling passages
94
to
98
are inclined in the central portion and cooling air flows therethrough from the lower surface of the platform
80
and out of the upper surface thereof. Thus, the entire portion of the platform
80
is cooled by the cooling air flowing therein and flowing out thereof.
In the representative prior art gas turbine moving blade platform as described above, there are provided linearly extending main cooling passages of the cooling passages
85
,
86
, and in addition thereto, there are provided a multiplicity of cooling passages of the cooling passages
87
to
90
,
91
to
93
, etc. which pass through the platform
80
at an angle and thus have a comparatively long inclined route. Hence, in the platform
80
, there are provided many such cooling air supply passages and processing or working of the platform itself becomes complicated, and thus it is necessary to develop a cooling structure for the platform which can be made simpler and still has an excellent cooling effect that will cool an entire portion of the platform uniformly.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a gas turbine moving blade platform in which supply passages and flow passages of platform cooling air are simplified so that processing of the platform is facilitated as well as an entire portion of the platform is cooled uniformly with result that a cooling effect thereof is enhanced.
In order to achieve said object, the present invention provides the following items (1) to (6):
(1) A gas turbine moving blade platform characterized in comprising a cavity formed in the platform around a base portion of the moving blade for introducing thereinto a cooling air. Also, a plurality of cooling holes communicate with the cavity and open at a peripheral end surface of the platform.
(2) A gas turbine moving blade platform as mentioned in item (1) above, characterized in that the plurality of cooling holes are provided at an angle so as to extend upwardly toward the peripheral end surface of the platform from the cavity.
(3) A gas turbine moving blade platform as mentioned in item (1) above, characterized in that there is provided an impingement plate at a bottom portion of the cavity for introducing therethrough the cooling air into the cavity.
(4) A gas turbine moving blade platform as mentioned in item (1) above, characterized in that there is provided a cooling hole passing through the platform at an angle, and communicating at its one end with the cavity and opening at its the other end at an upper surface of the platform.
(5) A gas turbine moving blade platform including two cooling passages, each being provided in the platform on each side of the moving blade, and communicating at its one end with a leading edge passage of the moving blade and having at its other end an opening at a side end surface of the platform. A cover is provided for closing the opening of each of the two cooling passages, and at least three linearly formed cooling passages are formed in the platform. Each of the linear cooling passages communicates at its one end with any one of the two cooling passages and has at its other end an opening at a rear end surface of the platform.
(6) A gas turbine moving blade platform characterized in that the platform includes an upper platform and a lower platform. A cavity is formed between the upper platform and the lower platform on each side of the ventral and dorsal sides of the moving blade. A cooling passage is bored in the upper platform along each of both side portions of the upper platform so as to communicate at its one end with the cavity at a front portion of the platform and its other end opens at a rear end surface of the platform. Also, a multiplicity of cooling holes are bored in the lower platform and pass upwardly through into the cavity thereabove from a bottom surface of the lower platform.
In the platform of item (1) above, the cooling air flows into the cavity formed around the moving blade and the platform around the moving blade forms almost the entire portion of the cavity, thereby substantially the entire platform is cooled uniformly by this cavity. Further, there are provided the plurality of cooling holes, communicating with the cavity, at the peripheral portions of the platform and the cooling air flows out thereof while cooling the peripheral portions. Thus, by the effect of the cavity and the cooling holes of the peripheral portions, the entire portion of the platform is cooled uniformly. Further, the complicated and lengthy cooling passages as seen in the prior art are eliminated and such a simple structure is realized as having only the cavity and the short cooling holes along the peripheral portions. The supply source of the cooling air to the cooling ho
Akita Eiji
Fukue Ichiro
Suenaga Kiyoshi
Tomita Yasuoki
Watanabe Koji
Mitsubishi Heavy Industries Ltd.
Verdier Christopher
Wenderoth , Lind & Ponack, L.L.P.
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