KR102063724B1 - Resonator for damping acoustic frequencies in combustion systems by optimizing impingement holes and shell volume - Google Patents

Abstract

The resonator in the combustor of the gas turbine includes a flow sleeve forming an air path to provide air flow to the combustion chamber of the combustor, and one or more impact holes disposed on the flow sleeve tuned to the damping frequency.

Description

RESONATOR FOR DAMPING ACOUSTIC FREQUENCIES IN COMBUSTION SYSTEMS BY OPTIMIZING IMPINGEMENT HOLES AND SHELL VOLUME}

The present invention relates to a gas turbine, and more particularly to the impact holes and shell volume formed in the sleeve of the gas turbine to form the resonator 140, thereby changing the air flow flowing through the combustion system to minimize the performance degradation of the combustor The present invention relates to a resonator for damping acoustic frequencies of a combustion system by optimizing impact holes and shell volumes.

For example, combustors such as those used in industrial gas turbines mix compressed air with fuel and discharge hot, high pressure gas downstream. The energy stored in the gas is then switched to operate, for example, as the hot and high pressure gas expands in the turbine, rotating the shaft to drive an attached device, such as a generator that generates electricity.

As the air / fuel mixture burns, the resulting hot gas produces a change in pressure. Such pressure fluctuations at some frequencies (eg, 1-1000 Hz) create acoustic pressure through the system. Accordingly, the combustion system is susceptible to high cycle fatigue (HCF) generated from such combustion dynamics. If the frequency of vibration is not taken into account, the structural integrity of the combustion system can be compromised, resulting in catastrophic failure.

Methods of preventing the excitation of natural frequencies in a system are known. Negative pressure fluctuations that can produce natural frequencies can be reduced by redesigning the hardware, changing the air splits, or adding external resonators to the system. However, in a wide range of applications, for example industrial gas turbines, this can add significant cost or reduce combustion system performance as long time is required for testing and modification. Additionally, an external resonator for this purpose can reduce combustor performance as the resonator will need air for damping. Air will be removed from combustion to reduce the efficiency of combustion. This can lead to increased emission levels, metal temperatures and thermal stresses, all of which will affect the lifetime and performance of the structure of the system.

Embodiments of the present invention include one or more impingement holes disposed on a combustion chamber in which air and fuel are mixed and combusted, a flow sleeve forming an air path to provide air flow to the combustion chamber, and a flow sleeve tuned to a damping frequency. Resonator damping acoustic frequencies of the combustion system by optimizing impact holes and shell volume consisting of (impingement holes)

In another embodiment of the present invention, a resonator in a combustor of a gas turbine is a collision consisting of a flow sleeve forming an air path for providing air flow to the combustion chamber of the combustor, and one or more impact holes disposed on the flow sleeve tuned to a damping frequency. Optimizing the hole and shell volume provides a resonator that damps the acoustic frequencies of the combustion system.

The combustor of a gas turbine according to an embodiment of the present invention includes a combustion chamber in which a mixture of air and fuel is combusted; A flow sleeve defining an air path for providing an air flow to the combustion chamber; And one or more impingement holes disposed on the flow sleeve tuned to a damping frequency.

The one or more impingement holes and the shell volume of the combustor form a Helmholtz resonator tuned to the damping frequency.

At least one of the one or more impact holes is disposed at an anti-node position in the combustor.

The at least one impact hole is characterized in that it is cylindrical.

The at least one collision hole is characterized in that the polygon.

The one or more impact holes have different shapes or different sizes.

A resonator according to another embodiment of the present invention is disposed on a resonator in a combustor of a gas turbine, the flow sleeve forming an air path for providing air flow to the combustion chamber of the combustor, and the flow sleeve tuned to a damping frequency. One or more collision holes.

The one or more impingement holes and the shell volume of the combustor form a Helmholtz resonator tuned to the damping frequency.

At least one of the one or more impact holes is arranged at an anti-node position in the combustor.

The at least one impact hole is characterized in that it is cylindrical.

The at least one collision hole is characterized in that the polygon.

The one or more impact holes have different shapes or different sizes.

A method of damping acoustic frequencies according to another embodiment of the present invention is a method of damping acoustic frequencies in a combustor of a gas turbine, wherein the air flows through an air path formed by the flow sleeve to form air and fuel mixture in the combustion chamber. Providing the combustion chamber; Combusting the air and fuel mixture in the combustion chamber; And generating at least one damping frequency through one or more impingement holes disposed on the flow sleeve tuned to the at least one damping frequency to damp the acoustic frequency generated by the combustion.

The one or more impingement holes and the shell volume of the combustor form a Helmholtz resonator tuned to the damping frequency.

At least one of the one or more impact holes is disposed at an anti-node position in the combustor.

The one or more impact holes have different shapes or different sizes.

The one or more impingement holes consist of a cylindrical or polygonal shape.

1 illustrates a combustion system of an exemplary gas turbine according to an exemplary embodiment.
2 shows a cross-sectional view of a combustor according to an exemplary embodiment.
3 shows a cross-sectional view of a resonator in accordance with an exemplary embodiment.
4 shows a schematic diagram of a resonator in accordance with an exemplary embodiment.
5A and 5B show exemplary shapes and sizes of crash holes in accordance with an exemplary embodiment.
Fig. 6 is a schematic diagram of a resonator according to another exemplary embodiment.

Various embodiments of acoustic resonators in a combustion system are described. However, it should be understood that the following description is merely illustrative of the devices and methods of the present disclosure. Accordingly, any number of reasonable, predictable modifications, changes and / or substitutions are contemplated without departing from the spirit and scope of the present disclosure.

1 shows a combustor 10 according to an exemplary embodiment. For illustrative purposes only, the combustor 10 is shown in FIG. 1 as applied to an industrial gas turbine 20. However, combustors of other applications can be applied without departing from the scope of the present invention. For the sake of explanation and consistency, like reference numerals refer to like elements in the drawings.

As shown in FIG. 1, air to be supplied to the combustor 10 is received through the air intake section 30 of the gas turbine 20 and compressed in the compression section 40. The compressed air is then supplied to the headend 50 via the air path 60. Air is mixed with fuel to burn at the tip of nozzle 70 and the resulting hot, high pressure gas is supplied downstream. In the exemplary embodiment shown in FIG. 1, the generated gas is supplied to the turbine section 80 where the energy of the gas is converted to work by the rotating shaft 90 connected to the turbine blade 95.

As can be seen in FIG. 1, the entire structure is connected to the combustor 10, so that the acoustic frequency caused by the generation of gas resonates through the entire system. Thus, controlling the generation of acoustic frequencies has a lasting impact on the operation, performance and lifetime of the overall system. The influence of frequency is not limited only to frequencies that resonate throughout the engine. The effects of the frequency on the combustion system, which occurs mainly in the combustor when high amplitude frequencies are generated, cause damage to the combustion system. This will require powering down the engine for repairs, thus creating a loss of revenue.

Another scenario is when an external damper is used in the combustor to reduce dynamic pressure.

In this case, the damper is most likely to degrade combustor performance because the damper needs air to operate. This air is removed from the combustion resulting in higher emissions, thus lowering performance. In addition, adding a resonator will shorten the stop period due to the high thermal stress of the resonator.

2 is a cross-sectional view of an exemplary combustor 10. Combustor 10 includes one or more fuel nozzles 70 at headend 50. It should be understood that there may be more than one combustor 10 in any given gas turbine. Liner 150 and transition piece 160 channel the generated high pressure, hot gas into turbine section 80.

3 is a cross-sectional view of a resonator in accordance with an exemplary embodiment. As shown in FIG. 3, the flow sleeve 100 is surrounded by a shell 110 forming a shell volume 120. The flow sleeve 100 is formed around the liner 150 and the diverter 160 such that air flows in the space formed between the flow sleeve 100 and the liner 150 and the diverter 160. The flow sleeve 100 is compressed and forms thereon one or more impingement holes 130 through which relatively hot air flows. Thus, the collision holes 130 and the shell volume 120 form a Helmholtz resonator (ie, resonator 140). Using the shell volume 120 and the impact hole 130 as a Helmholtz resonator typically eliminates the need to design an external resonator that siphons the airflow flowing through the combustion system to degrade combustor performance.

4 is a schematic diagram of a resonator 140 formed by shell volume 120 and impingement hole 130 in accordance with an exemplary embodiment. Shell volume 120 acts as the compliance or volume of the Helmholtz resonator, while impingement hole 130 simulates the neck of the Helmholtz resonator.

The resonator 140 may be optimized by adjusting the size, thickness, shape, and position of the collision hole 130. The impingement hole 130 on the flow sleeve 100 forming the resonator 140 has a wavelength extending to the flow path 100 and the liner 150 and to the air path location between the flow sleeve 100 and the diverter 160. You can damp the denomination with.

In particular, the middle range of frequencies (eg, between 20-200 Hz) can be damped by using existing hardware in the combustor 10 in accordance with an exemplary embodiment. However, other frequencies may be targeted without departing from the scope of the present invention. Moreover, multiple impact holes 130 can be formed and designed to target several frequencies at one time.

The air flow through the impact holes 130 can be controlled to improve damping. For example, different sizes and shapes of impact holes 130 may be used to target different frequencies with different damping capabilities.

5A and 5B show exemplary shapes and sizes of impact holes 130.

The size of the hole 110 can be varied by adjusting the diameter D and / or thickness T. For example, the cylindrical shape of FIG. 5A produces higher damping than the trapezoidal shape of FIG. 5B as the neck effective length increases. Moreover, the change in the trapezoidal angle of FIG. 5B causes an additional shift in acoustic frequency. Although only two exemplary shapes are shown in FIGS. 5A and 5B, other shapes may be used without departing from the scope of the present invention.

6 is a schematic diagram of an exemplary embodiment of a resonator 140. For example, by connecting impingement holes 130 and 130 'having different diameters, thicknesses and / or shapes, the unstable frequency can be damped. Additionally, the impact holes 130 ″ may be disposed on or near the mode-shaped anti-node of the targeted wave and its frequency.

Some of the advantages of the exemplary embodiments are that the lifetime of the hardware can be extended by reducing the amplitude of the combustion dynamic pressure or pressure wave, thereby extending, decreasing or eliminating the combustion dynamic pressure for frequencies between 20-200 Hz, And the use of existing hardware in the combustion system, eliminating the need to add an external resonator for low-mid range frequencies or the need to change the design of the hardware to minimize the effects of combustion dynamics and reduce sound pressure fluctuations.

It will also be appreciated that the disclosure herein is not limited to combustion systems of industrial gas turbines. For example, aero gas turbines and combustion systems of gas turbines may generally also realize the benefits of the present disclosure. Moreover, the shape, size and thickness of the impact holes are not limited to those disclosed herein.

For example, collision holes of squares, rectangles, triangles, and other polygonal structures such as pentagons, hexagons, and octagons for naming some examples may also realize the benefits of the present disclosure. In addition, any combination of impact holes having different sizes, thicknesses and shapes can be connected together to adjust the frequency of the resonator without departing from the scope of the present invention.

The breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents. Moreover, the advantages and features described above are provided in the described embodiments, but should not limit the application of the claims to processes and structures that achieve some or all of the above advantages.

In addition, section headings herein are provided for consistency with the proposals under 37 CFR 1.77 or to provide an organizational cue. Such headings should not limit or characterize the invention described in all claims that may be issued in this disclosure. Moreover, the description of the technology in "Background" should not be construed as an admission that the technology is prior art of any invention in this disclosure. "Brief Summary" is not to be regarded as a characteristic of the invention as described in the claims found herein. Moreover, any reference to singular “invention” in this disclosure should not be used to assert that there is only one novelty claimed in this disclosure. Numerous inventions may be presented in accordance with the limitations of the numerous claims associated with the present disclosure, and the claims define the invention and equivalents thereof protected thereby. In all cases, the scope of the claims should be considered as their advantage in view of the specification, but should not be limited to the headings described herein.

Claims (17)

In the combustor of a gas turbine,
A combustion chamber in which a mixture of air and fuel is combusted;
A flow sleeve defining an air path for providing an air flow to the combustion chamber; And
One or more impact holes disposed on said flow sleeve tuned to a damping frequency,
One of the neighboring pair of collision holes has an upper diameter less than or equal to a lower diameter and is disposed at an anti-node position within the combustor, and the other is disposed at a node position within the combustor with an upper diameter greater than the lower diameter. , Combustor of gas turbine. The method of claim 1,
And the shell volume of the one or more impingement holes and the combustor form a Helmholtz resonator tuned to the damping frequency. delete The method of claim 1,
And the at least one impact hole is cylindrical. The method of claim 1,
Wherein the one or more impingement holes are polygonal. The method of claim 1,
Wherein the one or more impingement holes have different shapes or different sizes. In a resonator in a combustor of a gas turbine,
A flow sleeve forming an air path for providing air flow to the combustion chamber of the combustor, and
One or more impact holes disposed on said flow sleeve tuned to a damping frequency,
One of the neighboring pair of collision holes has an upper diameter less than or equal to a lower diameter and is disposed at an anti-node position within the combustor, and the other is disposed at a node position within the combustor with an upper diameter greater than the lower diameter. , Resonator. The method of claim 7, wherein
And the shell volume of the one or more impingement holes and the combustor form a Helmholtz resonator tuned to the damping frequency. delete The method of claim 7, wherein
And the at least one impact hole is cylindrical. The method of claim 7, wherein
And the at least one impact hole is a polygon. The method of claim 7, wherein
And the one or more impingement holes have different shapes or different sizes. A method of damping acoustic frequencies in a combustor of a gas turbine,
Providing an air stream to the combustion chamber through an air path formed by the flow sleeve to form the air and fuel mixture in the combustion chamber;
Combusting the air and fuel mixture in the combustion chamber; And
Generating at least one damping frequency through one or more impingement holes disposed on the flow sleeve tuned to at least one damping frequency to dampen the acoustic frequency generated by combustion,
One of the neighboring pair of collision holes has an upper diameter less than or equal to a lower diameter and is disposed at an anti-node position within the combustor, and the other is disposed at a node position within the combustor with an upper diameter greater than the lower diameter. , How to damp acoustic frequencies. The method of claim 13,
And the shell volume of the one or more impingement holes and the combustor form a Helmholtz resonator tuned to the damping frequency. delete The method of claim 13,
And wherein said at least one impact hole has a different shape or different size. The method of claim 13,
Wherein the one or more impingement holes are cylindrical or polygonal.

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