JPH0110401Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates generally to stator or rotor blades of land-based combustion turbines, and more particularly to convection-cooled blade members of stator or rotor blades having an improved fluid cooling structure. be.

It is well known that the power output and operating efficiency of a combustion turbine can be improved by increasing its inlet operating temperature. However, the inlet operating temperature is limited by the maximum allowable temperatures of the turbine stator and rotor blades. Additionally, as the stator and rotor blade temperatures increase as the inlet operating temperature, or inlet gas temperature, increases, the rotor blades are susceptible to damage from the tensions and stresses normally associated with turbine operation. Become. Proper cooling of the stator and rotor blades increases the inlet operating temperature while maintaining the temperature of the stator and rotor blades below the specified maximum operating temperature of the materials of which the stator and rotor blades are constructed. can be done.

Many existing cooling structures use methods such as convection, film, and seepage methods to cool the stator or rotor blades of a turbine. Convectively cooled airfoils are advantageous over film-cooled and exudate-cooled versions in many turbine applications because there is no need to form holes in the surface of the airfoil. This is because the holes in the surfaces of the blade members of turbines operating on heavy oil fuel can become clogged with deposits, rendering the blade cooling system ineffective. In many blade cooling configurations, cooling air is drawn from the compressor section of the turbine and passes through separate channels within the turbine to reach the stator or rotor blades. For rotor blades, cooling air drawn from the compressor section typically passes through a flow path along the turbine rotor;
Each of several turbine rotor discs is reached. Each rotor disc may define a plurality of cooling air passages that communicate cooling air to a plurality of vane roots secured to a circumferential portion of the rotor disc. Cooling air passages in each rotor blade communicate cooling air from the blade root throughout the blade member. Typically, the stator blades of a turbine are communicated with cooling air by a dedicated cooling structure of the same type.

The cooling structure of the turbine stator or rotor blades is
The objective is to perform this cooling while minimizing the flow rate of cooling air required for effective cooling of the wing members. This is because the air drawn from the compressor section for cooling reduces the amount of air that ultimately drives the rotor blades of the turbine, thereby reducing the overall efficiency of the combustion turbine.

One way to minimize the cooling air flow rate is to increase the cooling air velocity in the cooling air passages. However, increasing the cooling air velocity increases the pressure loss per unit length of the cooling air passage. Typical convection-cooled airfoils according to the prior art are characterized by long cooling air passages, and the turbine supply pressure to the cooling air passages is
Limited by the aerodynamic design of the turbine, the cooling air passages of conventional convection-cooled blade members are
Typically, cooling air velocity is low and limited. Adequate cooling under limited supply pressure is achieved by increasing the cross-sectional area of the cooling air passages and the cooling air flow rate.

The recent trend toward higher inlet operating temperatures of combustion turbines has created a need to improve the cooling efficiency of convectionally cooled airfoil members of turbine stators or rotor blades. However, prior art convective cooling structures for turbine stator or rotor blades are believed not to provide an adequate means of effectively increasing the efficiency of the blade cooling system for the reasons discussed above.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to overcome the cooling air velocity limitations associated with prior art convection-cooled airfoils and provide a convection-cooled airfoil with improved cooling efficiency without increasing cooling air flow. It is to be.

To this end, the present invention provides a convection-cooled blade member for a stator or rotor blade of a combustion turbine, having a leading edge, a trailing edge, and a tip, the blade member extending from the leading edge to the trailing edge. It has a first cavity as a supply cavity, a second cavity as a discharge cavity, and a third cavity as a supply cavity in the span direction, which are sequentially arranged and compartmentalized towards the space, and are spaced apart from each other. a hollow wing spar defining concave and convex sides, and a metal shell joined to the spaced apart concave and convex sides of the spar and substantially enclosing the concave and convex sides; The shell is formed with a plurality of convective cooling passages extending substantially chordwise between the metal shell and the hollow wing spar, and further includes a plurality of convection cooling passages extending substantially chordwise between the metal shell and the hollow wing spar, and further directs cooling air into at least the first and third cavities. a through hole fluidly communicating the first and third cavities and the convection cooling passage to supply the cooling air from the first and third cavities into the convection cooling passage; a through hole fluidly communicating the convection cooling passage and the second cavity to discharge exhaust of the cooling air used to cool the wing member from the convection cooling passage to the second cavity; and a device for discharging the cooling air used to cool the wing member from the second cavity.

In this way, in the convection-cooled wing member of the present invention, by alternately providing cooling air supply cavities and exhaust cavities within the wing spar, the length of the cooling air passage between adjacent cavities can be reduced. The relatively short length allows effective high-speed convective cooling of the wing member while minimizing the airflow available to the wing cooling system. Therefore, the blade members of the turbine stator or rotor blades are effectively convectively cooled without adversely affecting the overall operating efficiency of the combustion turbine.

For a more detailed understanding of the invention, it is advantageous to read the following description of a preferred embodiment, given by way of example only, with reference to the accompanying drawings.

FIG. 1 shows, in cross section, a blade (blade member) 10 of a land combustion turbine constructed in accordance with the principles of the present invention. The wing 10 includes a frame-like airfoil strut or spar 12 on which a metal shell 1 is attached.
One or more layers of metal sheets forming the wing spar 12 are bonded to wrap around the wing spar 12. Cooling air passages (convection cooling passages) 16 arranged as described later
is formed by the connection between the wing spar 12 and the metal shell 14. That is, the cooling air passages 16 may be defined by channels in the metal shell 14 as shown in FIG. 2, channels in the wing spar 12 (not shown), or a combination of both channels (not shown). can.

Wing spar 12 defines a plurality of cavities 18 . FIG. 1 shows first, second and third spaces 18a, 1 which are sequentially arranged and sectioned from the leading edge to the trailing edge.
A preferred embodiment of the invention is shown having 8b and 18c. The front cavity 18a and the rear cavity 18c are used as cooling air supply cavities.
These feed cavities are pressurized with a cooling air flow from the compressor section of the turbine (not shown). Therefore, between the compressor section (not shown) and these supply cavities there is a device (not shown) which conveys the cooling air to the supply cavities. The cooling air in the supply cavities 18a, 18c is supplied through a plurality of holes in the wing spar 12 to a plurality of generally chordwise cooling air passages 16. These holes are arranged in one or more double rows of holes 30, 36, 38 that span the length of the wing 10.

For the supply cavities 18a and 18c, the wing spars 12
Each vent in the cooling air passages 16 provides cooling air flow to one or more cooling air passages 16 .
terminates in a through hole in the wing spar 12 in the discharge cavity 18b or at the trailing edge 24 of the wing 10. Thus, the exhaust cavity 18b receives the cooling air flow from the supply cavities 18a, 18c and discharges the cooling air through the blade tip holes (exhaust device).

In the embodiment shown in FIG.
There are six separate paths that cooling air can take through. For example, cooling air that enters one of the through holes 30a in the through hole row 30 passes through a cooling air passage that passes through the leading edge of the blade 10 in the chord direction, and then passes through the cooling air passage that passes through the leading edge of the blade 10 in the chord direction. It is discharged into the discharge space 18b through the through hole 32a. Similarly, the cooling air entering the through hole 30b of the through hole row 30 of the supply cavity 18a passes through the cooling air passage 16 chordwise along the convex side of the blade 10, and passes through the corresponding through hole 34a. and is discharged into the discharge cavity 18b. The other four possible cooling air flow paths start from each one of the four rows of holes 36a, 36b, 38a, 38b in the rear supply cavity 18c and pass through the exhaust cavity 18b. Hole 34b, trailing edge 24 of wing 10, through hole 32b of discharge cavity 18b, each terminating in trailing edge 24 of wing 10. FIG. 3 depicts the void and air flow conditions in a combustion turbine rotor blade constructed in accordance with the present invention.

The mass-void structure of the airfoil 10 provides a convection-cooled airfoil that is not subject to severe cooling rate limitations as described in connection with the long cooling air passages of typical prior art convection-cooled airfoils. In accordance with the present invention, a plurality of cavities are used to direct a cooling air flow through a plurality of short cooling air passages at high speed in order to convectively cool substantially the entire outer surface of the airfoil 10. The amount of air utilized is thereby reduced and the overall turbine efficiency is improved.

Although the embodiments described above utilize generally chordwise cooling air passages between the holes in the spar 12, any chordwise and chordwise cooling air passages may be used to maximize effective convective cooling of the wing 10. The cooling air passages may be arranged according to a combination of spanwise patterns. It will also be appreciated that the wing 10 may be configured to have any odd number of cavities greater than the three shown in FIG. As the number of cavities used increases, the length of the cooling air passageway that conveys cooling air from one cavity to an adjacent cavity correspondingly decreases. Therefore, it is appropriate to use three or more cavities for high temperature applications. For embodiments using 5, 7 or more voids,
The front and rear cavities are preferably supply cavities;
The adjacent cavities therebetween are made to function alternately as discharge cavities and supply cavities.

FIG. 4 shows, in cross-section, a combustion turbine stator blade or vane 50 constructed in cooperation with a rotor blade constructed in accordance with the principles of the present invention.
Stator blades 50 are supported in a turbine casing (not shown), typically between an inner arcuate shroud 52 and an outer arcuate shroud 54. In this embodiment, cooling air 51
is supplied to the forward and aft supply cavities 18a, 18c by coolant supply passages (not shown) in the outer shroud 54 that are in fluid communication with a compressor section (not shown) of the combustion turbine. The cooling air is supplied to a discharge device or discharge port 5 connected to a downstream low pressure point.
8 and is discharged from the discharge cavity 18b. Although not shown in FIG. 4, cooling air may be discharged through the trailing edge of the stator blades 50, similar to the structure described above with respect to FIG.

FIG. 5 shows, in elevation, a modified embodiment of a combustion turbine stator vane 70 constructed along the same lines as the embodiment of FIG. According to this variant embodiment, the cooling air 71 is supplied to the stator vanes 5 in FIG.
In the same manner as in 0, the front supply cavity 18a and the rear supply cavity 18c of the stator vane 70 are supplied. However, the cooling air is discharged from the inner shroud 5.
This is done through two evacuation devices or evacuation holes 72. The exhaust hole 72 is located downstream of the stationary seal 74, which seals the upstream space of the stator blade 70 from the downstream space, so that the discharged cooling air can flow through the turbine. It flows into the exhaust path of the driving high-pressure gas.

6, another modified embodiment of a combustion turbine stator vane 80 constructed in accordance with the principles of the present invention is shown in cross-section. The stator blades 80 are arranged in the discharge cavity 1
In the manner of discharging exhaust cooling air from 8b,
This embodiment is different from any of the embodiments described above. The stator vanes 80 are provided with cooling air exhaust holes 82 through the spar 12 and metal shell 14 for exhausting cooling air on their convex sides. Experiments have shown that there is almost no tendency for the surface holes on the convex side of the blade to become clogged even when operating on heavy oil fuel. The holes 82 are preferably arranged in double rows as shown in FIG. 6, but any arrangement that provides adequate exhaust flow may be used.

The embodiments shown in FIGS. 4 to 6 also have the cooling air passage 16 (space) described above, but since the cooling air passage 16 is normally provided as shown in FIG. Depending on the cutting method, it may not appear as shown in FIGS. 4 to 6.

[Brief explanation of drawings]

1 is a sectional view of a blade member of a stator or rotor blade of a combustion turbine according to an embodiment of the present invention; FIG. 2 is a sectional view showing a wall portion of the blade member shown in FIG. 1; The figure is an explanatory diagram showing the combustion turbine rotor blades and the air flow pattern inside them.
FIG. 5 is a sectional view showing a modified embodiment of the stator blade of the combustion turbine shown in FIG. 4; FIG. 6 is a fixed view of the stator blade shown in FIG. FIG. 7 is a sectional view showing another modified example of the child blade. 10... Wing (wing member), 12... Wing spar, 14...
...Metal shell, 24... Trailing edge, 16... Cooling air passage (convection cooling passage), 18a, 18c... Cooling cavity (first, third cavity), 18b... Discharge cavity (second cavity) location), 30a, 30b, 36a, 36b,
38a, 38b...Through holes that supply cooling air from the first and third cavities to the convection cooling passage, 32a, 32
b, 34a, 34b...through holes for discharging the cooling air used for cooling from the convection cooling passage to the discharge space;
50, 70, 82... Stator vane, 58... Discharge port (discharge device from the discharge cavity), 72... Discharge port (discharge device from the discharge cavity), 82... Discharge port (discharge device) empty space evacuation device).

Claims (1)

[Scope of utility model registration request] A convection-cooled blade member of a stator or rotor blade of a combustion turbine having a leading edge, a trailing edge, and a tip, the blade member having sections arranged in sequence from the leading edge to the trailing edge. span direction,
It has a first cavity which is a supply cavity, a second cavity which is a discharge cavity, and a third cavity which is a supply cavity,
a hollow wing spar defining spaced apart concave and convex sides; and a metal shell joined to and substantially enclosing the spaced apart concave and convex sides of the spar; The metal shell is formed with a plurality of convection cooling passages extending substantially chordwise between the metal shell and the hollow spar;
Further, a device for conveying cooling air into at least the first and third cavities is in fluid communication with the first and third cavities and the convection cooling passageway to convey the cooling air into the first and third cavities. The convection cooling passage and the second cavity are in fluid communication with each other, and the cooling air used to cool the blade member is discharged from the convection cooling passage. a convection cooling type of combustion turbine blade, comprising a through hole for discharging from the second cavity into the second cavity, and a device for discharging the exhaust of the cooling air used for cooling the blade member from the second cavity. Wing member.