JPH07332668A - Cooling structure for gas turbine combustor liner - Google Patents

Abstract

PURPOSE:To reduce the temperature of a liner wall by a method wherein the cooling of the liner wall is accelerated by increasing a liner wall-cooling calorie and increasing the flow-in quantity of cooling air to a cooling air hole as well. CONSTITUTION:Expanded heat transmission surface upstream ends 10 are provided to be close to cooling air holes 11, on the outer peripheral side of a liner 2. The expanded heat transmission surface upstream end 10 is provided in such a manner to be projected on a vertical surface of the cooling air hole 11. Then, cooling air hole jetting axes are provided to be tilted in the flowing direction of a combustion gas.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a cooling structure for a gas turbine combustor liner.

[0002]

2. Description of the Related Art As a conventional technique, Japanese Patent Publication Sho 59-49493 is available.
As described in the publication, cooling air flowing outside the gas turbine combustor liner is extended to the inside of the liner where the combustion gas flows through a plurality of cooling holes provided in the circumferential direction of the liner, and the cooling air flows in the flow direction of the combustion gas through a lip. It had a structure that spews out. In this structure, the liner is mainly provided in the circumferential direction of the liner by the convection cooling by the cooling air on the outer surface of the liner and the pressure difference between the pressure on the cooling air side on the outer side of the liner and the pressure on the inner side of the liner through which the combustion gas flows. The liner wall was cooled by film cooling with cooling air flowing through the cooling air holes. Due to the above structure,
Even if the outer surface of the liner is wavy, it is a flat surface,
The plane was the cooling surface area. The cooling air hole has a structure in which a plurality of cooling air holes are formed in the liner circumferential direction as communication holes between the outside and the inside of the liner.

[0003]

When the combustor liner is cooled, convection cooling is strengthened to reduce the amount of cooling heat that the film cooling takes, which in turn reduces the amount of cooling air used for film cooling. , Use the surplus air as combustion air. By improving the combined cooling air hole inlet state, cooling air can easily flow into the cooling air hole.

[0004]

An enlarged heat transfer surface is provided on the outside of a combustor liner through which cooling air flows to make contact L with the cooling air and to promote heat dissipation. The upstream end of the expanded heat transfer surface is provided close to the air hole for film cooling. The upstream end of the enlarged heat transfer surface is provided so as to project above the vertical surface of the air hole. It is characterized in that the upstream end of the expanded heat transfer surface is provided in the vicinity of the cooling hole whose ejection axis is inclined in the flow direction of the combustion gas.

[0005]

Since the enlarged heat transfer surface that comes into contact with the cooling air is provided outside the combustor liner through which the cooling air flows, the temperature of the cooling air is reduced to T
_c , the temperature of the combustor liner wall is T _w , the surface area before providing the expanded heat transfer surface is A ₀ , the surface area of the expanded heat transfer surface is A ₁ , the heat transfer coefficient of the liner wall is α, and the cooling heat quantity is q. , The cooling heat quantity q is expressed by the following equation.

Q = α (A ₀ + A ₁ ) (T _w −T _c ). The approximate cooling heat amount increases as the surface area of the expanded heat transfer surface increases. Generally, the heat transfer coefficient α is provided by providing the expanded heat transfer surface. Also increases, so the amount of cooling heat also increases accordingly. The film-cooling cooling air that cools the liner flows into the combustion gas side through the cooling hole due to the pressure difference between the cooling air side and the combustion gas side, but it is enlarged near the cooling hole to cool the heat transfer surface. Since the upstream end in the air flow direction is provided, the cooling air colliding with the upstream end of the expanded heat transfer surface is decelerated and the pressure is restored, so that the cooling air is more likely to flow into the cooling holes and the air flow rate for film cooling is increased. .

Further, in the shape in which the upstream end of the expanded heat transfer surface is projected on the vertical surface of the air hole, the cooling air colliding with the upstream end of the expanded heat transfer surface on the vertical surface of the air hole is directed in the flow direction of the cooling air. Cooling air that is about to flow and air that is about to flow into the combustion gas side through the cooling holes are disturbed, further increasing the heat transfer coefficient at the upstream end of the expanded heat transfer surface, and cooling the liner wall by the expanded heat transfer surface. Further promote.

In the case where the tip of the enlarged heat transfer surface is provided in the vicinity of the cooling hole whose ejection axis is inclined in the flow direction of the combustion gas, the enlarged heat transfer is performed together with the pressure increase at the tip of the enlarged heat transfer surface. Since the upstream end of the surface also functions as a guide vane, it facilitates the flow of cooling air, increasing the amount of air flowing into the cooling air holes.

[0009]

EXAMPLES Examples of the present invention will be shown. FIG. 9 is a configuration diagram of the gas turbine. The air pressurized and heated by the compressor is sent to the combustor. This air burns fuel in the combustor and becomes higher temperature combustion gas, which is sent to the turbine. This high-pressure, high-temperature gas can rotate the turbine to obtain power. For example, electricity can be obtained by connecting and rotating a generator as a load.

FIG. 10 is a block diagram of the above-mentioned combustor.
The air pressurized and heated by the compressor 1 is sent in the direction shown by the arrow, and the fuel supplied from another pipe is injected from the pilot burner 4c, F ₁ fuel nozzle 4a, F ₂ fuel nozzle 4b, Combustion occurs in the combustion zones of the combustion chamber R ₁ and the auxiliary combustion chamber R ₂ . The combustion gas is sent to the turbine 6 via the transition piece 7. High temperature combustion gas flows inside the liner 2 of the main combustion chamber R ₁ , and compressed air flows outside the liner 2. A part of this compressed air flows through the cooling air holes 11 provided in the wall of the liner 2 to the inside of the liner as film cooling air for the liner wall. The liner 2 wall is heated by the high temperature combustion gas (about 1450 ° C.) flowing inside, and the liner 2 wall temperature becomes high. On the other hand, although the air flowing outside the wall of the liner 2 is pressurized and heated, the temperature is lower than the combustion gas temperature (about 380 ° C.). Must be cooled so that the temperature is within the allowable material temperature.

As shown in FIG. 1, an enlarged heat transfer surface 9 is provided on the outer peripheral surface of the liner 2 of the main chamber through which air flows so as to increase the heat radiation area to the air. The expanded heat transfer surface upstream end 10 is provided close to the cooling air hole 11 so that the air that has collided with the expanded heat transfer surface upstream end 10 can easily enter the cooling air hole 11. The length of the enlarged heat transfer surface 9 in the air flow direction may be continuous between the cooling air hole 11 and the next cooling air hole 11 as shown in FIG. 2, but is shown in FIG. Enlarged heat transfer surface upstream end 1
If it is divided into a plurality of 0s, the cooling of the liner wall is further promoted by the edge effect (leading edge effect) at the upstream end of the expanded heat transfer surface. 4 to 7 are examples in which the upstream end of the enlarged heat transfer surface 9 is provided so as to protrude above the vertical surface of the cooling air hole 11. In addition to the edge effect of the upstream end of the enlarged heat transfer surface 9, the upstream end 10 of the enlarged heat transfer surface acts as an inflow guide vane into the cooling air hole 11, so that cooling air easily enters the cooling air hole 11. In the example shown in FIG. 8, the upstream end of the enlarged heat transfer surface 9 is provided close to the cooling air hole 11, and the cooling air hole injection shaft 12 is provided.
Is inclined by α degrees in the direction of combustion gas flow,
The air flowing through the cooling air holes 11 is the upstream end 10 of the expanded heat transfer surface.
The pressure recovery in the section and the upstream end of the expanded heat transfer surface 9 work together with the function of the guide vanes to facilitate the flow (easy return flow). Up to now, the case where the cooling air easily flows into the cooling air hole and the cooling effect is large by increasing the cooling air flow rate has been described. However, when the cooling of the liner wall has a margin, the diameter of the cooling air hole 11 is reduced. Thus, the amount of cooling inflow air can be reduced, and the reduced air can be used as premixed combustion air to bring about another effect of further reducing NOx.

Although the cooling of the liner 2 of the main combustion chamber R ₁ has been described here, a similar configuration is effective for the cooling of the sub chamber liner 5 of the auxiliary combustion chamber R ₂ shown in FIG. Cooling can be done.

[0013]

Since the enlarged heat transfer surface 9 is provided on the outer surface of the combustor liner, the heat transfer area of the expanded heat transfer surface is A ₁ , and the cooling heat quantity is q.
Then, the relationship of q = α (A ₀ + A ₁ ) (T _w −T _c ) ... (1) is established, and the approximate cooling heat amount increases as the heat transfer area of the expanded heat transfer surface increases.

Where α is the heat transfer coefficient of the liner wall, A _{0 is} the surface area before the enlarged heat transfer surface is provided, T _{w is} the temperature of the liner wall,
_Tc : Air temperature.

Since the expanded heat transfer surface 9 is provided on the cooling air passage surface with respect to the original smooth surface of the outer wall of the liner, the heat transfer coefficient α of the smooth surface is
_Since α / α ₀ > 1 with respect to _{0, the} amount of cooling heat increases according to the equation (1) as α increases. Therefore, since the amount of cooling heat can be increased by the increase in the heat transfer coefficient together with the increase in the area of the expanded heat transfer surface, the liner wall can be effectively cooled by providing the expanded heat transfer surface.
Since the enlarged heat transfer surface upstream end 10 is provided close to the cooling air hole 11, the air collides with the enlarged heat transfer surface upstream end 10 and decelerates to recover the pressure, so that the cooling air easily flows into the cooling air hole 11. Therefore, the amount of cooling air can be increased, and the liner wall can be effectively cooled by film cooling.

Since the upstream end 10 of the expanded heat transfer surface is provided so as to protrude above the vertical surface of the cooling air hole 11, the cooling air can easily flow into the cooling air hole 11 for the above-mentioned reason. It serves as a guide vane for the inflowing air into the holes 11, the cooling air is more likely to flow into the cooling air holes 11, and the amount of the cooling air can be increased, so that the liner wall can be effectively cooled by the film cooling. .

Since the direction of the injection axis 12 of the cooling air hole 11 is inclined in the combustion gas flow direction, the air colliding with the upstream end 10 of the enlarged heat transfer surface easily flows into the cooling air hole 11 and the amount of cooling air increases. Therefore, the effect of cooling the liner wall film can be promoted.

[Brief description of drawings]

FIG. 1 is a partial perspective view of a liner of an enlarged heat transfer surface.

FIG. 2 is a partial view of a side surface of a liner showing a configuration of an enlarged heat transfer surface.

FIG. 3 is a partial side view of the liner.

FIG. 4 is a partial side view of the liner showing a state in which the upstream end 10 of the enlarged heat transfer surface projects onto the vertical surface of the cooling air hole 11.

FIG. 5 is a partial side view of the liner.

FIG. 6 is a partial side view of the liner.

FIG. 7 is a partial side view of the liner.

FIG. 8 is a partial side view of the liner showing a state in which the ejection axis of the cooling air hole is inclined in the combustion gas flow direction.

FIG. 9 is a configuration diagram of a gas turbine.

FIG. 10 is a cross-sectional view showing the structure of a combustor.

FIG. 11 is a partial side view of a liner showing a conventional film cooling structure.

[Explanation of symbols]

1 ... compressor, 2 ... liner, 3 ... fuel, 4a ... F ₁ fuel nozzle, 4b ... F ₂ fuel nozzle, 4c ... pilot burner, 5 ... subchamber liner, 6 ... turbine, 7 ... transition piece, 8 ... Lip, 9 ... Enlarged heat transfer surface, 10 ... Enlarged heat transfer surface upstream end, 11 ... Cooling air hole, 12 ... Cooling air hole injection shaft.

Claims (3)

[Claims] 1. A gas turbine combustor liner characterized in that an enlarged heat transfer surface is provided on the outer peripheral side of the liner of the gas turbine combustor, and the upstream end of the expanded heat transfer surface is provided close to the cooling air hole. Cooling structure. 2. The cooling structure for a gas turbine combustor liner according to claim 1, wherein the upstream end of the enlarged heat transfer surface provided on the outer peripheral side of the combustor liner is provided so as to protrude to the vertical surface of the air hole. 3. An upstream end of an enlarged heat transfer surface is provided on the outer peripheral side of the combustor liner, close to an air hole whose ejection axis direction is inclined in the flow direction of combustion gas. The cooling structure for a gas turbine combustor liner according to claim 1.