KR20060016917A - Fuel nozzle and gas turbine compressor comprising the same - Google Patents

Abstract

The present invention provides a fuel nozzle having an excellent spraying performance such as droplet size, spray angle, spray flow uniformity, and spray particle size, with a cooling effect of a fuel nozzle without using an external device, and a gas turbine having the same. It is an object of the present invention to provide a combustor, and in order to achieve the above object, the present invention provides a nozzle body having an interior in which a fuel flow path is formed and an outlet in which a fuel injection hole is formed so that fuel is sprayed into the combustor through the fuel flow path. And a shroud surrounding the nozzle body, the shroud having an air inlet portion through which the shroud air is introduced, and an air outlet portion formed at a portion corresponding to the fuel injection hole so that the shroud air flows out, and between the nozzle body side and the shroud. So that the shroud air pivots inclined about the fuel flow path axis so that between the shroud and the nozzle body Provides a fuel nozzle having the swirler such that flow along the flow path group.

Description

 Fuel nozzle and gas turbine compressor comprising the same

1 is a cross-sectional view showing a gas turbine combustor having a fuel nozzle according to the present invention;

Figure 2 is an exploded perspective view showing the separation of the fuel nozzle according to the invention,

3 is a cross-sectional view illustrating the shroud air flow in the fuel nozzle of FIG. 2;

4 is a front view illustrating the swirler of FIG. 2;

5A is a graph showing spray angle and flow uniformity when the swirler of FIG. 2 is not adopted;

5B is a graph showing spray angle and flow uniformity when a swirler having a swirl angle of 40 ° is adopted,

5C is a graph showing spray angle and flow uniformity when a swirler having a swirl angle of 50 ° is adopted,

Fig. 6 is a graph showing droplet diameters when and without the swirler of the present invention.

Explanation of symbols on the main parts of the drawings

10: gas turbine combustor 30: combustor liner                 

40: burner case 60: igniter

100: fuel nozzle 110: nozzle body

110s: fuel flow path 112: fuel inlet hole

115: fuel injection hole 120: shroud

120s: air passage 122: air inlet

125: air outlet 130: swirler

132: inclined plate

The present invention relates to a fuel nozzle and a gas turbine combustor having the same, and more particularly, to a gas turbine fuel nozzle having a structure in which the droplet size of the fuel flowing into the combustor is reduced and the droplet distribution is improved, One is a gas turbine combustor.

Among the various types of fuel nozzles used in gas turbine combustors, the pressure spray fuel nozzles are fuel nozzles with a mechanism for converting the pressure energy applied to the fluid into atomized energy, as well as gas turbines, diesel engines, industrial combustors, and domestic boilers. It is used very widely.

In this case, in a small gas turbine combustor such as an auxiliary power unit (APU), fuel is sprayed into the combustor by using a pressure spray type fuel nozzle which does not normally have a swirler causing swirling flow. In the case of a pressure spray fuel nozzle not equipped with such a swirler, the fuel nozzle is exposed to a high temperature environment inside the combustion chamber, thereby damaging the fuel nozzle. That is, the fuel nozzles are exposed to high temperatures in the combustion chamber, which results in nozzle damage and orifice blockage due to deposition of combustion residues, which in turn affects spray performance such as spray angle, spray flow distribution, and spray particle size. There is a problem in that the efficiency and combustion stability of the entire combustor are lowered.

In order to compensate for the problem of the pressure spray fuel nozzle, a small amount of air (Shroud Air, Anti-carbon Air) can be flowed around the fuel nozzle. This air flow prevents the deposition of carbon components in the cooling combustion products of the fuel nozzle. However, in this case, the shroud air flows in only one direction, and thus there is a problem in that it does not affect spraying performance such as spray angle, spray flow distribution, and spray particle size except for cooling action of the fuel nozzle.

The present invention is to solve a number of problems, including the above problems, such as droplet size, spray angle, spray flow uniformity and spray particle diameter with the cooling effect of the fuel nozzle without using a separate external device An object of the present invention is to provide a fuel nozzle having an excellent spraying performance, and a gas turbine combustor and auxiliary power unit including the same.

In order to achieve the above object, the present invention includes a nozzle body having an interior in which a fuel flow path is formed and an outlet in which a fuel injection hole is formed, allowing fuel to be sprayed into the combustor through the fuel flow path, and the nozzle body. A shroud disposed between the nozzle body side and the shroud, the shroud having an air inlet portion through which shroud air is introduced, and an air outlet portion formed at a portion corresponding to the fuel injection hole so that the outside air flows out; Provided is a fuel nozzle with a swirler that allows shroud air to pivot inclined about the fuel passage axis to flow along an air passage between the shroud and the nozzle body.

The swirler is preferably formed with a plurality of inclined plates formed to be inclined from the fuel flow path axis, in this case, it is more preferable that the inclined plates have an inclination angle of 30 degrees to 60 degrees from the fuel flow path axis.

On the other hand, the gas turbine combustor in another aspect of the present invention, a combustor liner having a pressure spray fuel nozzle having the structure as described above, the interior in which the atomized fuel from the pressure spray fuel nozzle is combusted, and And an igniter for igniting fuel sprayed from the pressure sprayed fuel nozzle in the combustor liner.

In this case, the combustor case is formed outside the combustor liner, and shroud air from a gas turbine compressor is introduced into the air inlet through a space between the combustor case and the combustor liner.

Preferably, the combustor liner is of annular countercurrent shape.

Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.                     

1 shows a gas turbine combustor 10 with a fuel nozzle 100 in accordance with an embodiment of the present invention. This gas turbine combustor 10 is especially used for auxiliary power units (APU). Here, the auxiliary power unit is usually a small gas turbine engine is mainly used as the aerial and ground starter of the aircraft main engine serves to supply the emergency and auxiliary power of the aircraft. This auxiliary power unit can generate both electric and pneumatic power simultaneously, so it can be used in various fields on the ground as well as in aviation.

Referring to FIG. 1, a gas turbine combustor 10 according to a preferred embodiment of the present invention includes a combustor liner 30, a fuel nozzle 100, and an igniter 60.

Combustor liner 30 has an interior where the atomized fuel from fuel nozzle 100 is combusted.

The fuel nozzle 100 sprays liquid fuel such as kerosene into the combustor liner 30. In this case, a combustor case 40 is formed outside the combustor liner 30, and a part of the shroud air from the gas turbine compressor 20 flows into the air inlet 112 of the shroud (see FIG. 2), which will be described later. It is preferable to spray through the inside of the fuel nozzle and sprayed into the combustor liner 30.

The igniter 60 is a device that burns by igniting the fuel sprayed from the fuel nozzle 100 mixed with compressed air.

Referring to the operation of the gas turbine combustor 10 having this structure, compressed air is introduced into the combustor liner 30 through the compression blade 22 of the gas turbine compressor 20. In this state, fuel is injected into the combustor liner 30 through the fuel nozzle 100, and combustion occurs when the igniter 60 generates an electric spark behind the fuel nozzle. Due to this combustion, the expanded compressed air is discharged to the outside while working while rotating the expansion blade 52 of the turbine 50.

Here, the combustor liner 30 preferably has an annular countercurrent shape. That is, the compressed air introduced into the combustor liner 30 located behind the gas turbine compressor through the gas turbine compressor 20 is combusted by the igniter at the rear, and the burned and expanded air is the expansion blade 52 located at the front. To reduce the size of the combustor.

The fuel nozzle 100 according to the embodiment of the present invention provided in the gas turbine combustor 10 having such a structure is preferably a pressure spray fuel nozzle. A pressure atomized fuel nozzle injects fuel at a high pressure from the fuel nozzle and allows the fuel to atomize using a high relative speed due to the pressure difference between the injected fuel and the compressed air in the combustor liner. Unlike the air blast nozzle, the pressure atomized fuel nozzle does not need to flow air into the fuel nozzle at a high speed, so the structure of the fuel nozzle is simple and simple to manufacture, and a separate high speed air inlet device is provided. Is unnecessary and manufacturing cost is reduced.

The structure of the fuel nozzle 100 according to the embodiment of the present invention is shown in FIGS. 2 and 3. 2 and 3, the fuel nozzle 100 according to the embodiment of the present invention includes a nozzle body 110, a shroud 120, and a swirler 130. The nozzle body 110 has a fuel inlet hole 112 through which the fuel is introduced, a fuel flow path 110s is formed therein, and a fuel injection hole 115 is formed at the outlet, so that the fuel is supplied to the fuel. It is sprayed into the combustor, that is, into the combustor liner 30 through the flow path 110s and the fuel injection hole 115. In this case, as shown in FIG. 2, the nozzle body 110 may be formed by combining the nozzle body 110a having the fuel inlet hole 112 and the nozzle tip 110b having the fuel injection hole 115 coupled thereto. Alternatively, it may alternatively be formed integrally.

The nozzle body 110 is wrapped by the shroud 120. In this case, the shroud 120 includes an air inlet 122 through which the shroud air flows and an air outlet 125 through which the shroud air flows out. In this case, the air outlet 125 is formed to include the position where the fuel injection hole 115 of the nozzle body 110 is formed to allow the shroud air to flow out.

A swirler 130 is disposed between the side of the nozzle body 110 and the shroud 120. The swirler 130 pivots the shroud air inclined with respect to the fuel flow path to flow along the air flow path 120s between the shroud 120 and the nozzle body 110.

The swirler 130 may have various structures for pivoting shroud air between the shroud 120 and the nozzle body 110. For example, as illustrated in FIGS. 3 and 4, a plurality of inclined plates 132 are formed in the swirler 130 so as to be inclined from the axis of the fuel flow path 110s, and thus the shroud is formed. Air can simply be swung along these ramp plates 132.                     

As the shroud air pivots through the swirler 130, the shroud air flow increases the radial and tangential direction velocity components of the fuel droplets at the outlet of the fuel nozzle 100. . This causes the fuel to be sprayed into the combustor along the shroud air, thereby increasing the radius, swirl velocity component of the fuel spray, and consequently the spray angle of the fuel. In general, as the spray angle is increased, the atomization performance is improved, along with the increase in combustion performance and combustion stability.

In addition, the swirl flow increases the radial and tangential direction velocity components of the fuel nozzle outlet, thereby reducing the droplet size at both the injection center and the periphery, and spraying the point where the maximum droplet size appears. It is more biased to the outer area. This improves fuel spray symmetry compared to the maximum droplet size of a pressure atomized fuel nozzle with a conventional hollow circular spray structure occurs near the spray center.

Here, when the plurality of inclined plate 132 formed to be inclined from the fuel flow path 110s axis in the swirler 130, the inclined plate 132 is an inclination angle of 30 degrees to 60 degrees from the fuel flow path axis It is more preferable to have an inclination angle of 50 degrees, since the pattern factor of the combustor outlet is improved by 10% or more during combustion, as compared with the case where the inclined plate 132 is not provided, as will be described later. to be.

The effect by the fuel nozzle according to the present invention can be more clearly understood by the following spray characteristics test and combustion test results.

<Spray Characteristics Test>

In this case, a PDA (Phase Doppler Anemometry) measuring technique was used as the spray characteristic measuring apparatus. For this purpose, an adaptive phase / doppler velocimetry (APV) device using an Ar-ion laser with a maximum output of 5W was used. In this experiment, kerosene was used as a fuel, and all spray experiments were performed at room temperature and atmospheric pressure. In this case, the fuel supply pressure was 5 bar.

The experiments were conducted with the fuel supply pressure of 5 bar without the shroud air supply, and with the turning angles of 0 °, 40 ° and 50 °, respectively, at 5 bar fuel supply pressure and the shroud air supply pressure. The spray flow field characteristics were examined. The fuel flow rate here at 5 bar fuel pressure is 5.05 kg / hr.

1. Symmetry of spray angle and spray flow

5A to 5C show the flow field distribution when there is no swing flow, when the swing angle is 40 ° and when the swing angle is 50 °, respectively. 5a to 5c, it can be seen that the distribution of the flow field in the case where no swirling flow is present has a considerably narrower flow area compared to the case in which the swirling flow is present. In other words, the axial velocity component at the initial stage of the fuel nozzle outlet does not diffuse much in the radial direction and shows a high velocity near the axial center, and shows a considerably high velocity even downstream of 50 mm or less. However, as shown in FIGS. 5B and 5C, in the case of the swirl flow, it can be observed that the air flow at the outlet of the fuel nozzle is diffused in the radial direction very much. It can be seen that the increase significantly. This shows that the presence of fuel spray in the air flow field can significantly improve the spray angle of the fuel spray.

In addition, it can be seen that the symmetry of the entire flow is considerably improved in the case of the swirl flow compared to the case where the swirl flow does not exist in terms of the uniformity of the flow. In other words, the arrows in Figures 5a to 5c represent the velocity of each of the droplets, in the case of no swirling flow, the arrows are different in size due to the different sizes of the arrows. It can be seen that.

2. Average particle diameter of fuel

6 shows the droplet size distribution in the radial direction according to the turning flow and the turning angle change. In this case, the droplet size was measured by the mean mean diameter (SMD) and the droplet size was compared at a point 70 mm away from the nozzle outlet in the spray downstream direction. Referring to FIG. 6, droplets of a small size are distributed in the central portion as a whole, and the droplet size increases as the spray main region is moved. In this case, it can be seen that the droplet size is reduced in both the central portion and the spray main region due to the swirl flow supplied through the swirler.

Combustion experiment

Combustion experiments were performed using the gas turbine combustor performance test facility of Korea Aerospace Research Institute. Under the conditions of full power 397kPa, total temperature 482.2K, shroud air flow rate 0.84kg / sec, fuel flow rate 58.08kg / hr, the turning angle is 0 °, 40 °, with 5bar fuel supply pressure and shroud air supply pressure, respectively. The pattern factors at the exit of the combustor when the fuel nozzle with the swirler of 50 ° were employed were compared, respectively.

As shown in [Table 1], it can be seen that the outlet temperature of the fuel nozzle equipped with the swirler is significantly improved compared to the case where the swirl component is not supplied to the shroud air. In particular, it can be seen that the outlet temperature distribution is improved by 10% or more, especially when the turning angle is 50 °.

[Table 1]

Turning angle 0 ° Turning angle 40 ° Turning angle 50 ° Average temperature (K) 884 881 885 Temperature (K) 1141 1101 1048 Pattern factor (%) 38 32.7 26.9

According to the present invention having such a structure, by supplying the shrouded air of the swirl component to the fuel nozzle, not only the effect of cooling the fuel nozzle, but also the droplet size is reduced, and the droplet distribution is improved.

In addition, the swirler is provided with an inclined plate so that the swirl component of the shroud air is increased in the radial and swirl velocity components of the outlet velocity field. Accordingly, the radial direction of the fuel spray due to this radius, the rotational speed component is diffused, and as a result, the spray angle of the fuel spray weapon is increased.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and any person skilled in the art to which the present invention pertains may have various modifications and equivalent other embodiments. Will understand. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (6)

A nozzle body having an interior in which a fuel flow path is formed and an outlet in which a fuel injection hole is formed, such that fuel is sprayed into the combustor through the fuel flow path; A shroud surrounding the nozzle body and having an air inlet portion through which shroud air is introduced and an air outlet portion at which the shroud air flows out at a portion corresponding to the fuel injection hole; And And a swirler disposed between the nozzle body side and the shroud such that the shroud air is pivoted about the fuel flow path axis to flow along the air flow path between the shroud and the nozzle body. The method of claim 1, And a plurality of inclined plates formed in the swirler so as to incline from the fuel passage shaft to pivot the shroud air. The method of claim 2, And the inclined plates have an inclination angle of 30 degrees to 60 degrees from the fuel passage shaft. A pressure atomized fuel nozzle having any one of claims 1 to 3; A combustor liner having an interior in which the atomized fuel from the fuel nozzle is combusted; And And an igniter for igniting fuel sprayed from the fuel nozzle in the combustor liner. The method of claim 4, wherein The combustor case is formed outside the combustor liner, Shroud air from a gas turbine compressor is introduced into the air inlet through the space between the combustor case and the combustor liner. The method of claim 4, wherein And the combustor liner has an annular countercurrent shape.

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