JPS5870004A - Gas turbine wheel - Google Patents

Abstract

PURPOSE:To improve the riliability of strength against centrifugal stress and thermal stress, by providing a cooling groove on the inner diameter side of a wheel in stead of in the bottom of a groove for inserting a moving vane, and drilling a cooling hole connecting to the side surface of the wheel, in a moving vane cooling apparatus. CONSTITUTION:Wheels 1a, 1b are joined by a bolt 3, and a slit 10 is provided in the joined surfaces. Cooling grooves 12a, 12b are circumferentially provided in the outer circumferences of the wheels 1a, 1b, and cooling holes 11a, 11b are drilled from the side surfaces of the wheels 1a, 1b. Cooling air enters the cooling holes 11a, 11b through the slit 10, is distributed throughout the circumference uniformly via the cooling grooves 12a, 12b and is led via cooling grooves 13a, 13b into the moving vanes. Thus since the cooling holes 11a, 11b are positioned more inner circumferential positions than in the case of the prior art, the riliability of strength against centrifugal stress and thermal stress can be improved, and the high circumferential speed can be readily effected.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wheel for a gas turbine, and particularly to a wheel suitable for a gas turbine equipped with air-cooled rotor blades.

In gas turbines equipped with air-cooled rotor blades, cooling air is introduced into the rotor blades by guiding the cooling air to the dovetail (a protrusion that secures the rotor blade to the wheel) of the rotor blade. A method is often used in which the rotor is introduced into the rotor blade through a hole drilled in the rotor blade. There are three methods that have been attempted in the past for introducing cooling air into the dovetail portion. - Figure 1 shows an example in which these three methods are adopted in one gas turbine. First, the first method is to attach the cover 21 to the outer circumferential side of the wheel 11 with a port 22 as shown in (a), seal between the cover 21 and the casing 23, and then connect the rotor blades to the cooling holes 20 provided in the cover 21. ．． Cooling groove provided at the base of 13. It guides cooling air to the

In this method, the cover 21 is attached to the wheel 1. Since the structure is close to a circular ring with an average diameter approximately equal to the outer diameter of the gas turbine, there is a drawback that centrifugal stress is large, which is an obstacle to increasing the circumferential speed of the gas turbine.

The second method is as shown in (b), in which the wheels 1. The arm 16 is extended near the outer periphery of the wheel 1b, and a seal plate 17 is inserted between both arms for sealing, and cooling air is introduced into the cooling groove 131 through a cooling hole 19 diagonally opened from the base of the arm 16. It is something that guides you. The cooling air passes through the gap between the wheel 1.0 bolt 3 and the bolt hole, and then passes through the gap between the wheel 1.0 bolt 3 and the bolt hole. It is introduced into the cooling hole 19 through the cooling hole 18 provided in the arm 25 of the coupling for the purpose of torque transmission between the engine and the wheel 1b.

In this method, the cooling holes 19 are connected to the rotor blades 4. Depending on the model, nearly 100 holes must be provided, and the machining time is often long. Also, since the cooling holes 19 must be opened diagonally, the cooling holes 19 and the cooling grooves 13. An acute angle is formed at the intersection with the centrifugal stress,
There is a drawback that stress concentration due to thermal stress becomes large and fatigue failure is likely to occur due to repeated starting and stopping.

The third method (as shown in O) is to sandwich the spacer 2 between the wheels 15 and 1, and connect the outer periphery of the spacer to the wheel 1b.
and a hook 15 with a circumference of 1°. and 15e, and cooling air is introduced into the cooling groove 13° through the slit 10 provided in the spacer 2. Cooling air is guided to the slit 10 through a hole provided in the center of the wheel 6. In this method, the outer periphery of the spacer 2 is the wheel 1. Cooling groove 13. This has the drawback that the outer diameter is necessarily large and becomes an obstacle to increasing the circumferential speed of the gas turbine.

An object of the present invention is to provide a gas turbine wheel that has high strength reliability against centrifugal stress and thermal stress and is equipped with a cooling air introduction system that enables a high peripheral speed of the gas turbine.

In the present invention, one or more circumferential grooves are provided on the outer periphery of the wheel, this groove is machined to the required depth on the inner periphery of the wheel, and a hole is provided that connects this groove with the side surface of the wheel. The above objective is achieved by: It is easy to understand that even if a rotating disk is divided into two pieces in the thickness direction, the stress in the disk hardly changes. Even if a deep groove is provided in the circumferential direction on the outer circumference of the wheel, It has almost no effect on stress. If the grooves (hereinafter referred to as dovetails) provided in the wheel for fixing the rotor blades are machined in the axial direction of the wheel, the circumferential grooves according to the invention will divide the dovetails in the axial direction. However, even in this case, the width of the dovetail increases only by the proportion that the axial width of the dovetail is reduced by the groove.
If the width of the groove is made small, there will be almost no effect. On the other hand, Hoi Jl.

The number of holes communicating with the circumferential grooves from the side surface can be any number regardless of the number of rotor blades, so the number may be the minimum number necessary in consideration of the flow rate of cooling air, etc. Since the circumferential groove can be made as deep as required, there is no need for the connecting hole to be inclined with respect to the wheel/L axis.At the same time, when using the conventional spacer, The outer diameter of the spacer can be reduced.

In order to describe the main points of the present invention in more detail, embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows an embodiment in which the present invention is applied to a gas turbine wheel that seals cooling air using an arm and a seal plate. Wheel 1. .

1 are connected by bolts 3, and a slit 10 is provided on the joining surface. Wheel 1. , dovetail 5. on the outer periphery of lb. , 5b are machined in the axial direction, and the rotor blades 4. ．． 4b
is inserted into the dovetail.

Dovetail 5-. A cooling groove 131°13 is provided at the bottom of the rotor blade 4-. It is closed by a protrusion provided on the dovetail portion of 4b.

Wheel 1. , lb has a cooling groove 13. ．． The arm 16. is located on the inner diameter side of the arm 13b. ．． 16- extends, and a sealing plate 17 is inserted between both arms to seal the leakage of cooling air. Wheel comb1. , Lb are provided with cooling grooves 12-. 12
cooling grooves 12.b are provided in the circumferential direction, and cooling grooves 12.b are provided from the side surfaces of the wheels la, lb. .

12, a plurality of cooling holes 1.1. , llb is opened. Cooling air is supplied to wheel 1 from a compressor (not shown).
．． , the cooling hole 11 through the center hole of 1b and the sulin) 10.
．． , llb, and are evenly distributed around the entire circumference in the cooling grooves 12, 13, and the cooling grooves 13. .

13, and is guided into the inside of the rotor blade.

Wheel 1. A perspective view of the outer periphery of is shown in FIG. 3. Cooling hole 11. It is not necessary to provide one film for each dovetail, and it is sufficient to provide as many films as necessary in consideration of the flow rate of cooling air.

According to this embodiment, the cooling holes 11-, llb are connected to the cooling grooves 13.
．． Since it is not necessary to make the hole diagonally toward the hole 13b, the end of the hole can be avoided from having an acute angle, and a wheel with high strength reliability against repeated centrifugal stress and thermal stress can be obtained.

Also, the cooling hole 11. .

Since the number of 11b is small, processing time can be shortened.

FIG. 4 shows an embodiment in which the present invention is applied to a gas turbine in which cooling air is sealed by a spacer.

The difference from Figure 2 is the wheel l.

10. A spacer 2 is inserted between the wheel 1b and the spacer 2, and the side surface of the spacer 2 is lined. ．． 10b are provided so that cooling air passes through these slits to the cooling holes 11. , llb.

According to this embodiment, the cooling holes 11. , llb, the outer diameter of the spacer 2 can be reduced to the position of .

FIG. 5 shows an embodiment in which the present invention is applied to a gas turbine wheel having dovetail grooves formed in the circumferential direction. The difference from Figure 2 is the dovetail 5. .

The only difference is that the cooling grooves 12.5b are machined in the circumferential direction in this embodiment. ．． 12b is a dovetail 5.
．． 5. Since there is no separation, there is an effect that there is no increase in stress at the dovetail portion.

According to the present invention, the cooling holes can be formed in the axial direction of the wheel, and at the same time, the cooling holes can be located close to the inner circumference of the conventional Yorimo wheel, so it is strong against centrifugal stress and thermal stress. This has the excellent effect of providing a gas turbine wheel that is highly reliable and can easily achieve high circumferential speeds.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional technology, FIG. 2 is a sectional view of a gas turbine showing an embodiment of the present invention, FIG. 3 is an enlarged perspective view of a part of FIG. 2, and FIG. 4 is a sectional view of a gas turbine according to an embodiment of the present invention. FIG. 5 is a sectional view of a gas turbine showing still another embodiment of the present invention. 1... Wheel, 2... Spacer, 4... Moving blade
5... Dovetail, 11... Cooling hole, 12...
cooling groove. 'i9hiri10 (艮) (b) (C)Me2 no 2 Jfy3r;EJ 4th mouth / ge, ra (i3 do

Claims (1)

[Claims] 1. A circumferential or axial groove provided on the outer periphery of a rotating disc-shaped wheel, a plurality of rotor blades having protrusions that fit into the grooves, and a rotor blade provided inside the rotor blade. , a device for cooling the rotor blade comprising a cooling hole for introducing cooling air from the inner diameter side of the wheel, a cooling groove in a circumferential direction provided on the outer periphery of the wheel, and a bottom of the cooling groove formed in the groove where the rotor blade is inserted. A gas star pin wheel characterized in that a plurality of cooling holes are provided so as to be closer to the inner diameter side of the wheel than the bottom of the groove of the nodule, and to connect side surfaces of the wheel.