JPH0451641B2 - - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION This invention relates to turbine blades, and particularly to turbine blades requiring cooling, such as those used in the first stage of industrial turbine engines.

[Background technology of the invention]

In turbine engines and the like, the turbine itself, which is driven by the combusting gases, typically drives a blower or compressor that supplies air to the combustor.
A self-driving system is used. The most effective way to increase the output rate of such a turbine is to
Although the temperature of the combustion gas at the turbine inlet is increased, the temperature is limited by the thermal stress resistance of the material forming the turbine blades or the ability to withstand high temperature oxidation, corrosion, etc.

Therefore, conventionally, convection type turbine blades are used which are provided with a flow path through which cooling fluid flows inside the blade. However, in the case of convection type turbine blades, the amount of cooling fluid used to maintain the turbine blade temperature within an allowable value is excessive for a given turbine inlet gas temperature, and is not satisfactory. It wasn't. That is, a large amount of cooling fluid obviously reduces the temperature of the blade, but conversely increases the aerodynamic loss of the blade and also reduces the turbine output efficiency. For this reason, the current situation is that there is a desire for the development of a device that can effectively cool the blades with a small amount of cooling fluid.

[Purpose of the invention]

The present invention was made in view of the above circumstances, and its purpose is to distribute cooling fluid within the blade in a well-balanced amount without reducing the turbine output, and to maintain each part of the blade in good condition. It is an object of the present invention to provide a turbine blade that can be cooled and manufactured at relatively low cost.

[Summary of the invention]

In order to achieve the above object, the present invention has an inlet at the proximal end of the blade root, and includes a cooling flow path leading from the inlet to the outside of the blade via the inside of the blade root and the inside of the blade body, In a turbine blade having an inlet connected to a cooling fluid supply,
A flow path provided in the leading edge of the blade and mainly guiding cooling fluid through a path formed along the height direction of the blade inside the blade root and inside the blade body, and a cooling fluid guided in the flow path. A first cooling channel is provided with a discharge hole for discharging the fluid to the outside of the blade body, and the first cooling channel is independently provided in the intermediate portion of the blade, and mainly directs the cooling fluid to the root portion of the blade. guided along a path formed along the height direction of the blade inside the blade body and inside the blade body, and then returned near the tip of the blade body in the height direction and guided to the vicinity of the base end of the blade body; Further, a bent flow path is returned from near the base end and guided to near the tip end in the height direction of the blade body, and the cooling fluid guided to at least the most downstream region of the bent flow path is discharged to the outside of the blade body. The second part is provided with a discharge hole to
The cooling flow path, the second cooling flow path and the first cooling flow path are independently provided within the blade trailing edge,
A flow path that mainly guides the cooling fluid through a path formed along the height direction of the blade inside the blade root portion and the inside of the blade body, and a flow path that guides the cooling fluid guided into the flow path from the trailing edge of the blade body. A third cooling channel including a channel for discharging to the outside; and a third cooling channel provided at the inlets of the first, second, and third cooling channels to adjust the flow rate of the cooling fluid flowing into each channel. It is characterized by being equipped with a flow rate adjustment mechanism.

〔Effect of the invention〕

As mentioned above, there are three completely independent
Since it is divided into two cooling channels, when the cooling fluid supply pressure to each cooling channel is constant, the cooling is lower than that of a conventional blade with only one or two internal channels. The fluid flow velocity can be increased, and as a result, the cooling effect by convection can be sufficiently enhanced compared to conventional blades. Therefore, as a result, the supply pressure of cooling fluid can be lowered compared to conventional blades, the amount of cooling fluid can be reduced, and aerodynamic losses can be reduced and efficiency can be improved. In addition, 3 formed within the wing
Since the two cooling channels are completely independent and each cooling channel is communicated with the cooling fluid supply section separately, it is possible to prevent the pressures in each cooling channel from interfering with each other. As a result, the amount of cooling fluid flowing through each cooling channel can be set accurately, and the maximum cooling effect can be achieved with the minimum flow rate. Therefore, since the blade constituent material can be cooled well, the amount of cooling fluid can be further reduced, and efficiency can be further improved. In addition, since a flow rate adjustment mechanism is provided at the entrance of the three cooling channels to adjust the flow rate of the cooling fluid flowing into each channel, it is possible to adjust the flow rate adjustment mechanism without increasing accuracy during blade manufacturing. As a result, the flow rate of each cooling channel can be maintained at an appropriate value, and the above-described effects can be achieved while facilitating manufacturing.

[Embodiments of the invention]

FIG. 1 shows the appearance of an embodiment in which the present invention is applied to a rotor blade of a turbine. That is, this rotor blade is broadly divided into a blade body 1, a blade root portion 2 that supports the blade body 1, and a platform portion 3.

The blade body 1, blade root portion 2, and platform portion 3 are integrally formed by precision casting, leaving only the tip wall X (see Fig. 2) of the blade body 1. are joined by welding or diffusion bonding.

As shown in FIGS. 2 and 3, there are three cooling fluid systems 11, 12, 13 in the blade body 1 and the blade root 2, which extend in the height direction of the blade body 1.
are formed by partition walls 14, 15, and the ends of these cooling fluid systems 11, 12, 13 located inside the blade root 2 are connected to a cooling fluid supply path provided on a rotating shaft (not shown). ing. The partition wall 14 branches into two branch walls 14a and 14b near the wing body of the wing body 1, and these branch walls 14
a and 14b extend close to the inner surface of the tip wall X described above. A wall 17 forming a U-shaped flow path 16 is provided between the branch walls 14a and 14b.

Thus, the first cooling system 11 is formed by the partition wall 14 and a partition wall 18 provided near the leading edge F so as to extend from the blade root 2 to the vicinity of the tip of the blade body 1. straight channel 19
, a cavity 20 formed between the partition wall 18 and the outer surface of the front edge F, a plurality of small holes 21 provided in the partition wall 18, and a gap between the cavity 20 and the outer surface of the front edge F. It is composed of a plurality of discharge holes 23 for cooling the film provided in a wall 22 existing between the two. Therefore, the cooling fluid supplied to this first cooling system 11 flows from the blade root 2, flows through the flow path 19 in the blade height direction, and reaches the vicinity of the tip wall X. It gradually flows into the cavity 20 through a plurality of small holes 21 provided in the wall 22, and then flows out to the outside of the blade through a plurality of discharge holes 23 provided in the wall 22. In the figure, reference numeral 24 indicates a stirring strip which is protruded from both the inner surface of the blade dorsal side and the inner surface of the blade ventral side of the flow path 19 to enhance the convection cooling effect. The cooling performance of the cooling system 11 shown in FIG. 1 is mainly due to the convection cooling effect in the flow path 19 and the impingement cooling caused by the cooling fluid passing through the small hole 21 from the flow path 19 and impinging on the inner surface of the wall 22 as a jet. The convection cooling effect on the inner surface of the discharge hole 23 and the cooling fluid blown out of the blade through the discharge hole 23 are applied to the outer surface of the blade, that is, the leading edge F and the dorsal and ventral sides of this leading edge F. This is achieved by the synergistic effect of the film cooling effect caused by the flow along the film.

Thus, the second cooling system 12 is formed between the partition walls 14 and 15 and extends from the blade root 2 to the vicinity of the tip wall X of the blade body 1, and then communicates with the U-shaped flow path. Bent channel 31 and this bent channel 31
The main body is a plurality of discharge holes 32 provided in the ventral wall of the wing body 1 constituting the blade body 1. Therefore, the cooling fluid led to the second cooling system 12 flows between the partition walls 14 and 15 from the blade root to the tip of the blade body 1, and then flows around the leading edge side. It returns 180 degrees and flows between the branch wall 14b and the wall 17, and then returns 180 degrees around the leading edge side at the base of the wing body 1 and flows through the branch wall 1.
4a and the wall 17 to near the tip of the blade. During this time, the air flows out of the blade from the discharge hole 32 provided in the ventral wall of the blade body 1 that constitutes the bent flow path 31 . In addition, 33 in the figure indicates a stirring strip provided similarly to the first cooling system 11, and 34
indicates a discharge hole provided in the tip wall X. The cooling performance of this second cooling system 12 is as follows:
1, the convection cooling effect in the discharge holes 32 and 34, and the film cooling effect caused by the cooling fluid blown out from the discharge holes 32 and 34 flowing along the ventral outer surface and the tip outer surface of the blade. It will be given to you.

In addition, since the cooling fluid is discharged to the outside of the blade from the discharge holes 32 at multiple points along the way of the bent channel 31, the amount of cooling fluid passing through it gradually decreases as it goes downstream, resulting in convection cooling. In this embodiment, the cross-sectional area of the passage decreases as it goes downstream, thereby keeping the flow rate approximately constant, since there is a risk that the effectiveness may decrease. Furthermore, from the viewpoint of reducing pressure loss in the flow path, the two return portions are formed into curvature paths that change smoothly.

Therefore, the third cooling system 13 is for cooling the trailing edge side of the blade, and the third cooling system 13 is for cooling the trailing edge side of the blade.
and a partition wall 41 provided on the trailing edge side of the blade body 1, and a flow path 42 extending in the height direction from the blade root 2 to the vicinity of the tip wall X of the blade body 1; and the trailing edge R of the wing body 1; a plurality of small holes 44 provided in the partition wall 41; and a wall existing between the cavity 43 and the trailing edge R. 45 and a plurality of discharge holes 46 provided therein. Therefore, the cooling fluid led to the third cooling system 13 flows from the blade root 2 through the flow path 42 toward the tip side of the blade body 1, and then passes through the small hole 44 into the cavity 43. and then flows out of the blade through the exhaust hole 46. In addition, 47 in the figure
indicates a stirring strip. The cooling performance of the third cooling system 13 is determined by the convection cooling effect in the flow path 42, the impingement cooling effect caused by the cooling fluid passing through the small holes 44 colliding with the inner surface of the wall 45 as a jet, and the discharge. This is provided by a convective cooling effect on the inner surface of the holes 46.

On the other hand, the first, second, and third cooling systems 11, 1
An orifice plate 51 that finely adjusts the flow rate of the cooling fluid flowing into each cooling system 11, 12, 13 is removably provided at the cooling fluid inlet located at the blade root portion 2 of No. 2, 13. This is based on the following reasons. That is, since the blade with the above configuration uses many so-called film cooling discharge holes that blow out cooling fluid from the inside of the blade to the outside, it is necessary to strictly distribute the flow rate between each cooling system. As a means of performing this distribution, it is possible to increase the accuracy during manufacturing, but it is difficult to increase the accuracy as a practical matter. Therefore, in this embodiment, a flow rate adjustment mechanism, that is, an orifice plate 51 is added to maintain the flow rate distribution at an appropriate value after manufacturing.

In this way, the inside of the turbine blade is divided into multiple elongated channels to increase the speed of the cooling fluid passing through the inside to enhance the convection cooling effect. Since it also uses the superimposed effect of cooling, cooling performance can be dramatically improved with a small amount of cooling fluid.

Note that the present invention is not limited to the embodiments described above. That is, in the first cooling system 11, impingement cooling is used together, but it is not necessarily necessary to use it together. In addition, the second cooling system 12
As shown in FIG. 5, a guide 61 may be provided at the return portion of the bent flow path 31 to reduce the flow resistance at this portion. Further, in the third cooling system 13, a film cooling discharge hole may be provided to communicate the flow path 42 and the cavity 43 with the outside of the blade in order to enhance cooling of both sides of the blade trailing edge R. Furthermore, the flow path shape at the rearmost edge may be a slit-like flow path 71 as shown in FIGS. 6a and 6b, or a slit-like flow path 71 as shown in FIGS.
A pin fin 72 may be provided in the cavity 43 to increase the heat exchange surface as shown in FIG.

Furthermore, in each cooling system, a discharge hole for film cooling may be provided in the tip wall X of the blade body 1.

[Brief explanation of drawings]

FIG. 1 is an external view of a turbine blade according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line P-P in FIG. 1 and viewed in the direction of the arrow, and FIG.
4 is a sectional view taken along line Q-Q in the figure and seen in the direction of the arrow; FIG. 4 is a local sectional view taken along line S-S in FIG.
The figure is a sectional view locally showing a modified example of a turbine blade according to the present invention, FIG. 7a is a longitudinal cross-sectional view of a main part in still another embodiment of the present invention, and FIG. 7b is a cross-sectional view of the main part. DESCRIPTION OF SYMBOLS 1...Blade body, 2...Blade root, 3...Platform part, 11...First cooling system, 12...Second cooling system, 13...Third cooling system.

Claims (1)

[Scope of Claims] 1. A cooling flow path having an inlet at the base end of the blade root and leading from the inlet to the outside of the blade via the inside of the blade root and the inside of the blade body, and supplying cooling fluid to the inlet. In a turbine blade connected to a blade, the cooling fluid is provided within the leading edge of the blade, and mainly guides cooling fluid through a path formed along the height direction of the blade into the inside of the blade root and the inside of the blade body. A first comprising a flow path and a discharge hole through which the cooling fluid guided in the flow path is discharged to the outside of the blade body.
The cooling flow path and the first cooling flow path are independently provided in the intermediate portion of the blade, and the cooling fluid is mainly formed inside the blade root portion and inside the blade body along the height direction of the blade. After being guided along the route, the blade is returned near the tip of the wing body in the height direction, guided to the vicinity of the base end of the wing body, and then returned from near the base end in the height direction of the wing body. a second cooling channel comprising a bending channel that guides the bending channel to the vicinity of the tip and a discharge hole that discharges the cooling fluid guided to at least the most downstream region of the bending channel to the outside of the blade body; The cooling flow path is provided in the trailing edge of the blade independently of the second cooling flow path and the first cooling flow path, and mainly forms cooling fluid inside the blade root and inside the blade body along the height direction of the blade. a third cooling flow path comprising a flow path that guides the cooling fluid along a path guided by the flow path and a flow path that discharges the cooling fluid guided in the flow path to the outside from the trailing edge of the blade body; A turbine blade comprising: a flow rate adjustment mechanism provided at the inlet of the third cooling channel to adjust the flow rate of the cooling fluid flowing into each channel. 2. A patent claim characterized in that the first, second, and third cooling channels are provided with discharge holes for discharging the cooling fluid to the outside of the blade along the outer surface of the tip portion in the height direction of the blade body. The turbine blade according to item 1. 3. The first cooling flow path includes a portion that guides the cooling fluid in the height direction of the blade body, and a cavity formed between this portion and the outer surface of the leading edge of the blade body;
Cooling fluid provided on a partition wall that partitions this cavity and the above-mentioned section and guided by the above-mentioned section is injected toward the inner surface of the wall section that exists between the outer surface of the leading edge of the wing body and the above-mentioned cavity. The turbine blade according to claim 1, characterized in that the blade comprises a plurality of small holes. 4. The turbine blade according to claim 1, wherein the return portion of the bent flow path in the second cooling flow path is formed as a curvature path that changes with a smooth curvature.