Combustion chamber nozzle that improves the spatial uniformity of the premixing, and gas turbine equipped with it

Abstract

Combustion chamber nozzle (100), which includes: several guide vanes (110) arranged radially on their outer circumferential surface, each guide vane (110) having an inner cavity (112) into which fuel is supplied, wherein the guide vane (110) has a profile (120) in cross-section, wherein at least one pressure surface (124) and / or suction surface (126) of the profile (120) has several nozzle holes (130) connected to the cavity (112) and arranged in the radial direction of the profile (120), wherein the guide vane (110) further comprises a pair of nozzle holes (140) arranged in a V-shape on a leading edge (122) of the profile (120), wherein the V-shaped nozzle hole pair (140) comprises a pair of outlets (142) with an outlet on a pressure surface (124) and an outlet on the suction surface (126) of the profile (120), wherein the V-shaped nozzle hole pair (140) forms an angle (α) which diverges outwards with respect to a horizontal plane above the leading edge (122), wherein the V-shaped pair of nozzle holes (140) forms an acute angle (β) radially outwards with respect to a vertical plane perpendicular to the horizontal plane.

Description

[0001] This application claims priority over Korean patent application No. 10-2019-0037847, filed on April 1, 2019. AREA

[0002] The devices and methods, which are consistent with the exemplary embodiments, relate to a combustion chamber nozzle and a combustion chamber for a gas turbine containing it, and in particular to a combustion chamber nozzle with improved uniformity of premixing of the fuel and air in its guide vane area and a gas turbine containing it. BACKGROUND

[0003] A gas turbine combustion chamber serves to mix air compressed by a compressor with a fuel, to burn the air-fuel mixture at a constant pressure to produce a high-energy combustion gas, and to transfer the combustion gas to a turbine, which in turn converts the heat energy of the combustion gas into mechanical energy.

[0004] The combustion chamber has a structure in which air compressed by the compressor is mixed with fuel in a combustion chamber housing and ignited and burned within a combustion chamber lining. The compressed air, flowing along an outer surface of a tube arrangement of the combustion chamber, is directed, for example, towards a combustion chamber nozzle and enters the annular combustion chamber housing to mix with the fuel.

[0005] The fuel can be supplied via several routes, one of which runs through guide vanes with a radially defined cross-section on the outer surface of the combustion chamber nozzle. This means that compressed air is supplied to an annular space between the combustion chamber nozzle and a surrounding cover band, while the fuel is injected through several nozzle holes formed in the guide vanes arranged in the annular space. This premixes the air and fuel, and the premix is ​​then transferred to the combustion chamber.

[0006] However, due to the structure of the guide vanes arranged in the narrow annular space, the number of nozzle holes is limited. In particular, due to technical and design constraints (e.g., limitations in processing technology, strength requirements to withstand heat stress or vibration, etc.), the placement of nozzle holes in the immediate vicinity of the cover strip is very limited.

[0007] With regard to the cross-sectional area of ​​the annular space, the uniformity of the premixing in the outer area tends to be thinner than in other areas due to the arrangement restrictions of the nozzle holes, although the area of ​​an outer region of the guide vane near the cover belt is larger.

[0008] If the air-fuel mixture becomes thinner in the outer area of ​​the guide vane, the mixture becomes locally thicker in other areas, leading to poor premix uniformity within the guide vanes. Highly heterogeneous premixed air-fuel mixtures result in combustion occurring in homogeneous areas, causing adverse effects such as increased combustion vibration and higher emissions, including carbon monoxide and nitrogen oxides. US 2002 / 0 174 656 A1 describes a burner nozzle with nozzle holes on the guide vanes. DE 10 2008 022 669 A1 describes a fuel nozzle. US 2008 / 0 095 622 A1 describes a profile of a guide vane with front-side cooling. US 2008 / 0 276 622 A1 describes a fuel nozzle. SUMMARY

[0009] The aspects of one or more exemplary embodiments create a combustion chamber nozzle that can improve the uniformity of the air-fuel premix, which is achieved in guide vanes arranged radially on the outer surface of the combustion chamber nozzle. Additional aspects are partly set forth in the following description and partly become apparent from the description or can be learned through practical application of the exemplary embodiments.

[0010] The problem is solved by the features of independent claim 1.

[0011] According to one aspect of an exemplary embodiment, a combustion chamber nozzle is provided comprising: several guide vanes arranged radially on its outer circumferential surface. Each guide vane contains an internal cavity to which fuel is supplied. The guide vane has a profile in cross-section, with at least one pressure surface and / or suction surface of the profile having several nozzle holes connected to the cavity in its vertical direction. The guide vane has two nozzle holes arranged in a V-shape as a pair of outlets based on a leading edge of the profile on both sides of the profile, the pair of nozzle holes forming an angle (α) that diverges outwards with respect to a horizontal plane above the leading edge.

[0012] The V-shaped pair of nozzle holes forms an acute angle (β) radially outwards with respect to a vertical plane perpendicular to the horizontal plane.

[0013] The pair of nozzle hole outlets can be symmetrical with respect to the leading edge.

[0014] The center of the nozzle hole outlets can be located in the radially outermost nozzle hole among the multiple nozzle holes.

[0015] The nozzle hole can be a straight hole with a constant cross-section.

[0016] The nozzle hole can be a diffuser hole whose cross-section gradually increases towards the outlet.

[0017] A center of the angle (α) formed by the V-shaped pair of nozzle holes, which diverges outwards with respect to the horizontal plane above the leading edge, may be located in the cavity, whereby two flow paths formed by the outlets of the nozzle holes may be separated from each other.

[0018] Additional aspects are partly explained in the following description and partly become obvious from the description or can be learned through the practice of the exemplary embodiments.

[0019] According to one aspect of an exemplary embodiment, a combustion chamber nozzle is provided comprising: several guide vanes arranged radially on its outer circumferential surface. Each guide vane may contain an internal cavity to which fuel is supplied. The guide vane may have a profile in cross-section, wherein at least one pressure surface and / or suction surface of the profile may be arranged in its vertical direction with several nozzle holes communicating with the cavity. The guide vane may include a V-shaped nozzle hole with a pair of outlets based on a leading edge of the profile on both sides of the profile, wherein the V-shaped nozzle hole may form an angle (α) that diverges outwards with respect to a horizontal plane above the leading edge.

[0020] The V-shaped nozzle hole can form an acute angle (β) radially outwards with respect to a vertical plane perpendicular to the horizontal plane.

[0021] The pair of outlets of the V-shaped nozzle hole can be symmetrical with respect to the leading edge.

[0022] The center of the outlets of the V-shaped nozzle hole can be located in the radially outermost nozzle hole among the multiple nozzle holes.

[0023] The V-shaped nozzle hole can be a straight hole with a constant cross-section.

[0024] The V-shaped nozzle hole can be a diffuser hole whose cross-section gradually increases towards the outlet.

[0025] A center of the angle (α) formed by the V-shaped nozzle hole, which diverges outwards with respect to the horizontal plane above the leading edge, may be located in the cavity, whereby two flow paths formed by the outlets of the V-shaped nozzle hole may be separated from each other.

[0026] The angle (α) of the V-shaped nozzle hole formed with respect to the horizontal plane above the leading edge can be in a range of 70 to 180 degrees.

[0027] The angle (β) of the V-shaped nozzle hole, which is formed with respect to the vertical plane above the leading edge, can be in a range of 20 to 50 degrees.

[0028] The angle (α) of the V-shaped nozzle hole formed with respect to the horizontal plane above the leading edge can be in a range of 70 to 180 degrees, while the angle (β) of the V-shaped nozzle hole formed with respect to the vertical plane above the leading edge can be in a range of 20 to 50 degrees.

[0029] According to one aspect of a further exemplary embodiment, a combustion chamber for a gas turbine is provided, comprising: several burners arranged along an annular combustion chamber casing. Each burner may include a combustion chamber nozzle that injects fuel for mixing with compressed air, several guide vanes arranged radially on an outer circumferential surface of the combustion chamber nozzle, each guide vane containing a cavity to which the fuel is supplied, and a shroud surrounding the combustion chamber nozzle to form an annular space that accommodates the guide vanes. The guide vane may have a profile in cross-section, with at least one pressure surface and / or suction surface of the profile having multiple nozzle holes connected to the cavity in its vertical direction.The guide vane may contain a V-shaped nozzle hole which includes a pair of outlets based on a leading edge of the profile on both sides of the profile, wherein the V-shaped nozzle hole may form an outwardly diverging angle (α) with respect to a horizontal plane above the leading edge.

[0030] The V-shaped nozzle hole can form an acute angle (β) radially outwards with respect to a vertical plane perpendicular to the horizontal plane.

[0031] The pair of outlets of the V-shaped nozzle hole can be symmetrical with respect to the leading edge.

[0032] The center of the outlets of the V-shaped nozzle hole can be located in the radially outermost nozzle hole among the multiple nozzle holes.

[0033] The V-shaped nozzle hole can be a straight hole with a constant cross-section.

[0034] The V-shaped nozzle hole can be a diffuser hole whose cross-section gradually increases towards the outlet.

[0035] A center of the angle (α) formed by the V-shaped nozzle hole, which diverges outwards with respect to the horizontal plane above the leading edge, may be located in the cavity, whereby two flow paths formed by the outlets of the V-shaped nozzle hole may be separated from each other.

[0036] The angle (α) of the V-shaped nozzle hole formed with respect to the horizontal plane above the leading edge can be in a range of 70 to 180 degrees.

[0037] The angle (β) of the V-shaped nozzle hole, which is formed with respect to the vertical plane above the leading edge, can be in a range of 20 to 50 degrees.

[0038] The angle (α) of the V-shaped nozzle hole formed with respect to the horizontal plane above the leading edge can be in a range of 70 to 180 degrees, while the angle (β) of the V-shaped nozzle hole formed with respect to the vertical plane above the leading edge can be in a range of 20 to 50 degrees.

[0039] According to one or more exemplary embodiments, the stratification of the air-fuel ratio distribution along all circumferential and radial directions is reduced because the combustion chamber nozzle contains the V-shaped nozzle hole, which forms a radially outward inclination, while two flow paths, i.e., the outlets, diverge in a V-shape, thereby obtaining an effect of improving the premixed state in which the uniformity of the air-fuel ratio is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The above and other aspects will become more apparent from the following description of the exemplary embodiments with regard to the accompanying drawings; they show: Fig. 1 a view illustrating the overall structure of a gas turbine according to an exemplary embodiment; Fig. 2 a view illustrating a flow of premixed air in a combustion chamber of a gas turbine according to an exemplary embodiment; Fig. 3 a cross-sectional view illustrating a structure in which a combustion chamber nozzle is arranged in a cover band according to an exemplary embodiment; Fig. 4 a view showing the guide vanes from direction “A” to Fig. 3 illustrated according to an exemplary embodiment; Fig. 5 along the line “BB” to Fig. 4 Cross-sectional view taken according to an exemplary embodiment; Fig. 6 along the line “CC” to Fig. 5 Cross-sectional view taken according to an exemplary embodiment; Fig. 7 a cross-sectional view illustrating another exemplary embodiment of a V-shaped nozzle hole; Fig. 8 a view illustrating a circumferential distribution of the air-fuel ratio at an outlet of an annular space between a cover band and a combustion chamber nozzle with or without a V-shaped nozzle hole; and Fig. 9 a view illustrating a radial profile of the air-fuel ratio, which corresponds to the circumferential distribution of the air-fuel ratio according to Fig. 8 corresponds to. DETAILED DESCRIPTION

[0041] Various modifications can be made to the embodiments of the disclosure, and there may be different types of embodiments. Consequently, specific embodiments are illustrated in the accompanying drawings, and these embodiments are described in detail in the description. However, it should be noted that the various embodiments are not intended to limit the scope of protection of the disclosure to a specific embodiment, but rather should be interpreted as encompassing all modifications, equivalents, or alternatives of the embodiments contained in the ideas and technical scopes disclosed herein. If, however, it is determined that a detailed explanation of related known techniques in describing the embodiments might unnecessarily obscure the main point of the disclosure, the detailed explanation will be omitted.

[0042] The terminology used here is solely for the purpose of describing specific embodiments and is not intended to limit the scope of protection of the disclosure. The singular forms "a," "an," and "the" as used here are intended to include the plural forms as well, unless the context clearly indicates otherwise. In this description, terms such as "comprise," "contain," or "have / include" should be interpreted as indicating the presence of such features, integers, steps, operations, elements, components, and / or a combination thereof in the description, but not precluding the presence or possibility of adding one or more other features, integers, steps, operations, elements, components, and / or combinations thereof.

[0043] Furthermore, terms such as "first," "second," etc., can be used to describe different elements, but these terms should not restrict the elements. The terms are simply used to distinguish one element from others. The use of such ordinal numbers should not be interpreted as limiting the meaning of the term. For example, the components assigned to such an ordinal number should not be restricted in terms of their order of use, arrangement, or the like. If necessary, each ordinal number can be used synonymously.

[0044] It should be recognized that terms relating to fastenings, coupling and the like, such as "connected" and "coupled", refer to a relationship in which the structures are either directly or indirectly secured or fastened to one another by intervening structures.

[0045] It is subsequently recognized that expressions such as "at least one of a, b or c" and "a, b and / or c" mean only a, only b, only c, both a and b, both a and c, both b and c, all of a, b and c or variations thereof.

[0046] Exemplary embodiments relating to the accompanying drawings are described in detail below. To clearly illustrate the disclosure in the drawings, some elements that are not essential for a complete understanding of the disclosure may be omitted, with the same reference numerals throughout the description referring to similar elements.

[0047] Fig. Figure 1 is a schematic view illustrating an internal structure of a gas turbine 1000 according to an exemplary embodiment, and Fig. Figure 2 is a view illustrating the flow of premixed air in a combustion chamber of a gas turbine.

[0048] An ideal thermodynamic cycle for a gas turbine can correspond to a Brayton cycle. The Brayton cycle consists of four thermodynamic processes, including an isentropic compression process (i.e., adiabatic compression), an isobaric combustion process, an isentropic expansion process (i.e., adiabatic expansion), and an isobaric heat release process. That is, in the Brayton cycle, the gas turbine draws air from the atmosphere, compresses the air to a high-pressure environment, burns an air-fuel mixture at a constant pressure to release thermal energy, expands this high-temperature combustion gas to convert the thermal energy of the combustion gas into kinetic energy, and releases the exhaust gas, which contains the remaining energy, into the atmosphere.The Brayton cycle as such can consist of four thermodynamic processes, including compression, heating, expansion and heat release.

[0049] The Gas Turbine 1000, which embodies the Brayton cycle, can contain a compressor, a combustion chamber, and a turbine, as shown in Fig. 1 is illustrated. Although the following description regarding Fig. Given that the description in the present disclosure is given, it can be largely applied to other turbine engines with a configuration similar to that of the one in Fig. The gas turbine illustrated in Figure 1 is equivalent to 1000.

[0050] In Fig. 1. Compressor 1100 of the gas turbine 1000 can draw in air from the outside and compress it. Compressor 1100 can supply the compressed air to a combustion chamber 1200 for combustion and also supply it to a high-temperature area within the gas turbine 1000 that requires cooling. Here, the intake air in compressor 1100 is compressed through an adiabatic compression process, thus increasing the pressure and temperature of the air flowing through compressor 1100.

[0051] The compressor 1100 of the gas turbine 1000 can be designed as a radial or axial compressor. Generally, a radial compressor is used for a small gas turbine. On the other hand, a multi-stage axial compressor is used for a large gas turbine, such as the one in Fig. Figure 1 illustrates a gas turbine 1000, used to compress a large volume of air. A rotating shaft of the compressor 1100 and a rotating shaft of the turbine 1300 are directly connected, so that the compressor 1100 is driven using some of the power output from the turbine 1300.

[0052] The combustion chamber 1200 can mix the compressed air supplied by the compressor 1100 with the fuel and burn the mixture at a constant pressure to produce high-energy combustion gas. Fig. Figure 2 illustrates an example of the combustion chamber 1200 provided in the gas turbine 1000. The combustion chamber 1200 is arranged downstream of the compressor 1100 such that several burners 1220 are arranged along an inner circumference of a combustion chamber housing 1210. The burners 1220 each contain several combustion chamber nozzles 1230 through which the fuel is sprayed into the air in the correct ratio and mixed with it to form a fuel-air premixture suitable for combustion.

[0053] The Gas Turbine 1000 can use a gaseous fuel, a liquid fuel, or a hybrid fuel consisting of a combination of both. It is important to create combustion conditions suitable for reducing the amount of exhaust gases, such as carbon monoxide and nitrogen oxides. Although controlling combustion is relatively difficult compared to diffusion combustion, a premixed combustion scheme has been increasingly used to achieve exhaust gas control. This scheme allows for a more uniform combustion temperature, thus advantageously reducing the localized high-temperature range where nitrogen oxides are generated.

[0054] In premixed combustion, the compressed air is mixed with the fuel pre-expelled from the combustion chamber nozzle 1230, and then enters a combustion chamber 1240. The premixed gas is initially ignited by an ignition device, and combustion is then maintained by supplying a mixture of fuel and air once the combustion has stabilized.

[0055] Because the combustion chamber 1200 in the gas turbine 1000 has a high-temperature environment, the combustion chamber 1200 requires suitable cooling. Fig. 2 The compressed air flows along the outside of a pipe assembly, which includes a channel assembly and a flow sleeve 1270, towards the combustion chamber nozzle 1230. The channel assembly comprises a lining 1250 and a transition piece 1260 to connect the burner 1220 and the turbine 1300, allowing the high-temperature combustion gas to flow through it. The channel assembly, heated by the high-temperature combustion gas, can be suitably cooled while the compressed air flows along the outside of the pipe assembly.

[0056] The high-temperature, high-pressure combustion gas generated by the combustion chamber 1200 is fed through the duct arrangement of the turbine 1300. In the turbine 1300, the combustion gas undergoes adiabatic expansion, impacting and driving several guide vanes arranged radially around a rotating shaft. This converts the thermal energy of the combustion gas into mechanical energy, which rotates the shaft. A portion of the mechanical energy obtained from the turbine 1300 is supplied as the energy required to compress the air in the compressor, while the remainder is used as available energy to drive a generator to produce electrical power.

[0057] As described above, the combustion chamber 1200 has a structure in which the compressed air supplied by the compressor 1100 is mixed with the fuel in a region of a combustion chamber housing 1210 and a burner 1220 to form a premixture which is ignited and burned in a combustion chamber 1240 within a lining 1250. Fig. 2. The compressed air A, which has flowed towards the combustion chamber 1300 along an annular space between the lining 1250 and a flow sleeve 1270, forming a channel arrangement, enters the combustion chamber housing 1210 to mix with the fuel F1. The mixing of the fuel and air is carried out via several independent paths. Fig. 2 The fuel is injected by the guide vanes of the combustion chamber nozzle through the path through which a second fuel F2 is injected, so that a premix is ​​created between the annular space between the cover strip and the combustion chamber nozzle.

[0058] Due to the structure of the guide vanes arranged in the narrow annular space, the number of nozzle holes is limited. In particular, the arrangement of nozzle holes in the immediate vicinity of the shroud is very limited due to technical and design constraints. Because the uniformity of the premixing in the outer area of ​​the guide vane becomes less pronounced near the shroud than in other areas, such highly heterogeneous premixed air-fuel mixtures result in combustion occurring in homogeneous zones.

[0059] Fig. Figure 3 is a cross-sectional view illustrating a structure in which a combustion chamber nozzle 100 is arranged in a cover band 200 according to an exemplary embodiment. Fig. Figure 4 is a view showing the guide vanes 110 from a direction “A” towards Fig. 3 seen shows, Fig. 5 is one along the line “BB” to Fig. 4 cross-sectional views taken and Fig. 6 is one along the line “CC” to Fig. 5. Cross-sectional view. The combustion chamber nozzle 100 is described in detail with reference to the drawings described above.

[0060] The combustion chamber nozzle 100 can contain several guide vanes 110 arranged radially on its outer circumferential surface, each guide vane 110 containing a fuel-filled cavity 112. That is to say, the combustion chamber nozzle 100 can, without any particular restriction, have any type of combustion chamber nozzle, as long as the combustion chamber nozzle 100 contains the guide vanes 110 in which the premixing of air and fuel takes place.

[0061] In the combustion chamber nozzle 100, the guide vane 110 has a profile 120 in cross-section to ensure a uniform airflow. In this case, at least one pressure surface 124 and / or one suction surface 126 of the profile 120 cross-section can contain several nozzle holes 130 that communicate with the cavity 112. Therefore, the fuel supplied to the cavity 112 of the guide vane 110 is injected into the airflow through the small-diameter nozzle holes 130, thus premixing the air and fuel. The [image on the left] Fig. 4 nozzle hole 130 shown, which the guide vane 110 points in the direction “A” towards Fig. 3 is facing this, because the pressure surface 124 is viewed from the front due to the shape of the profile 120 of the guide vane 110.

[0062] The multiple nozzle holes 130 are uniformly arranged along a vertical direction of the pressure surface 124 or the suction surface 126 in order to achieve the most uniform possible equivalence distribution (EQ distribution) of the air-fuel ratio along a radial direction around the guide vane 110. Since the guide vanes 110 are arranged uniformly radially on the outer circumferential surface of the combustion chamber nozzle 100, a uniform distribution of the air-fuel ratio along the circumferential direction also appears. However, due to the structure of the guide vanes 110 arranged in the narrow annular space between the combustion chamber nozzle 100 and the cover band 200, the number of nozzle holes 130 is limited, and in particular, the arrangement of nozzle holes 130 in the immediate vicinity of the cover band 200 is very restricted.The uniformity of the premixing in the outer area of ​​the guide vane 110 near the cover strip 200 is slightly less than in other areas.

[0063] The exemplary embodiment can further include a nozzle hole with a special structure to mitigate the uneven distribution of the air-fuel ratio. The nozzle hole can be a V-shaped nozzle hole 140, which includes a pair of outlets 142 on both sides of a leading edge 122 of the profile 120.

[0064] The V-shaped nozzle hole 140 is arranged in a three-dimensional structure in the Fig. Figures 4 to 6 illustrate this. Because the nozzle hole 140 has a V-shaped overall form in the arrangement structure, the nozzle hole 140 is referred to as a "V-shaped nozzle hole" 140.

[0065] In Fig. Figure 4 contains the V-shaped nozzle hole 140, based on the leading edge 122 of the airfoil 120, with a pair of outlets 142 on both sides. That is, the V-shaped nozzle hole 140 has two flow paths distributed on both sides of the airfoil 120 based on the leading edge 122. The distribution of the outlets 142 on both sides of the leading edge 122 of the airfoil 120 is such that a uniform fuel mixture (i.e., a circumferential fuel mixture) is achieved in the area between the guide vanes 110, considering the airflow, which is divided by the leading edge 122 into the pressure area 124 and the suction area 126 as a boundary line.

[0066] In addition, the respective outlets 142 of the V-shaped nozzle hole 140 are oriented towards the airflow, so that the fuel injected from the V-shaped nozzle hole 140 meets the airflow, thus promoting mutual mixing.

[0067] Here, the pair of outlets 142 of the V-shaped nozzle hole 140 can be symmetrical with respect to the leading edge 122, so that it is not biased to one side for uniform premixing.

[0068] On the guide vane 110, two flow paths of the V-shaped nozzle hole 140 are arranged such that they form angles in two directions in three dimensions. One of these angles is the angle formed by the V-shape, i.e., the angle between the two flow paths. To express this, the V-shaped nozzle hole 140 can form an angle α that diverges outwards in a horizontal plane above the leading edge 122, with this angle being Fig. 5 is shown.

[0069] In Fig. Section 5 specifies the angle α at which the two flow paths open, the flow characteristics of the fuel flowing from the cavity 112 towards the outlet 142, and the impact angle for the airflow. Taking into account the design objectives, such as whether a uniform distribution of the fuel, a flexible flow, or effective impact angles for the airflow are prioritized, or whether all of these are appropriately harmonized, the angle α, which is formed in the horizontal plane above the leading edge 122, can be determined in the range of 70 to 180 degrees.

[0070] Additionally, the center C of the angle α, which is formed outwards through the V-shaped nozzle hole 140 on the horizontal plane above the leading edge 122, is located in the cavity 112 instead of in the thickness of the guide vane 110. Accordingly, the formation of the two flow paths of the V-shaped nozzle hole 140, which are to be separated from each other, may be desirable with regard to enabling the uniform flow and distribution of the fuel at the inlet of the flow path.

[0071] Furthermore, the V-shaped nozzle hole 140 can form another angle, which creates an acute angle β radially outward with respect to a vertical plane that intersects the leading edge 122. This acute angle β is in Fig. 6 shown. Due to this acute angle β, the V-shaped nozzle hole 140 forms an angle inclined to the cover strip 200, which differs from the case in which the several nozzle holes 130, which are formed along the vertical direction of at least one of the pressure surface 124 and / or the suction surface 126 of the profile 120, are formed horizontally.

[0072] To compensate for the problem of a thin air-fuel ratio in the area near the cover band 200, the V-shaped nozzle hole 140 is arranged to form an acute angle β radially outward with respect to the vertical plane above the leading edge 122. The V-shaped nozzle hole 140 causes fuel injection towards the cover band 200 to produce a richer fuel distribution than in the prior art, thereby reducing the unevenness of the air-fuel ratio distribution. The acute angle β in the vertical plane above the leading edge 122 can be in the range of 20 to 50 degrees.

[0073] It is recognized that, although the V-shaped nozzle hole 140 forms the acute angle β, which is directed radially outwards, the position of the outlet 142 cannot be restricted to this and can be modified or varied according to one or more other exemplary embodiments. Because the nozzle hole 130 and the V-shaped nozzle hole 140 are machined from the outside of the guide vane 110 inwards (e.g., by electro-erosion), the outlet 142 of the V-shaped nozzle hole 140 should be appropriately positioned. For example, the center of the outlet 142 of the V-shaped nozzle hole 140 can be positioned so as not to extend beyond the radially outermost nozzle hole 130 among the multiple nozzle holes.

[0074] The V-shaped nozzle hole 140 can be configured as a straight hole 144 with a constant cross-sectional area, as shown in the Fig. Figures 4 to 6 illustrate this. Although this configuration is general, the nozzle hole can be configured as a diffuser hole 146 whose cross-section gradually increases towards the outlet 142, as shown in Fig. Figure 7 illustrates this. The diffuser hole 146 can promote the compensation effect of the air-fuel ratio by spreading the distribution of the fuel injected from the outlet 142 over a wider area.

[0075] Fig. Figure 8 is a view illustrating the circumferential distribution of the air-fuel ratio at an outlet of an annular space between a cover band and a combustion chamber nozzle with or without a V-shaped nozzle hole, and Fig. Figure 9 is a view illustrating a radial profile of the air-fuel ratio, which corresponds to the circumferential distribution of the air-fuel ratio according to Fig. 8 corresponds to.

[0076] In Fig. Figure 8 shows that in the prior art combustion chamber nozzle 100 without the V-shaped nozzle hole 140, areas with different air-fuel ratios are layered like stripes, with the air-fuel mixture being particularly sparse in the area adjacent to the cover strip 200. In contrast, in the combustion chamber nozzle 100 of the exemplary embodiment with the V-shaped nozzle hole 140, the premixed state is improved, while the layering of the air-fuel ratio distribution is reduced, and the air-fuel ratio is also richer in the area adjacent to the cover strip 200.

[0077] Additionally, according to the in Fig.Figure 9 shows a radial profile of the air-fuel ratio (the variable of the vertical axis is, for example, a dimensionless R / Ro value with respect to the radius), and also significantly improves the amplitude (i.e., the deviation) between the minimum and maximum values ​​of the air-fuel ratio in the radial direction. This corresponds to the fact that, according to the exemplary embodiment with the V-shaped nozzle hole 140, the combustion chamber nozzle 100 reduces the stratification of the air-fuel ratio distribution compared to the prior art.

[0078] As described above, a combustion chamber 1200 for a gas turbine according to the exemplary embodiment comprises several burners 1220 arranged along an annular combustion chamber housing 1210, each burner 1220 being arranged in a cover band 200 with a combustion chamber nozzle 100 having a V-shaped nozzle hole.

[0079] While the exemplary embodiments have been described with respect to the accompanying drawings, those skilled in the field will recognize that various modifications in form and details can be made without deviating from the inventive concept and scope of protection as defined by the accompanying claims. Therefore, the description of the exemplary embodiments should be interpreted descriptively and not to limit the scope of protection of the claims, as many alternatives, modifications, and variations are obvious to those skilled in the field.

Claims

[1] Combustion chamber nozzle (100) comprising: several guide vanes (110) arranged radially on their outer circumferential surface, each guide vane (110) having an inner cavity (112) into which fuel is supplied, wherein the guide vane (110) has a profile (120) in cross-section, wherein at least one pressure surface (124) and / or suction surface (126) of the profile (120) has several nozzle holes (130) connected to the cavity (112) and arranged in the radial direction of the profile (120), wherein the guide vane (110) further comprises a pair of nozzle holes (140) arranged in a V-shape on a leading edge (122) of the profile (120), wherein the V-shaped nozzle hole pair (140) comprises a pair of outlets (142) with an outlet on a pressure surface (124) and an outlet on the suction surface (126) of the profile (120), wherein the V-shaped nozzle hole pair (140) forms an angle (α) which diverges outwards with respect to a horizontal plane above the leading edge (122), wherein the V-shaped pair of nozzle holes (140) forms an acute angle (β) radially outwards with respect to a vertical plane perpendicular to the horizontal plane. [2] Combustion chamber nozzle (100) according to claim 1, wherein the pair of outlets (142) of the V-shaped nozzle holes (140) is symmetrical with respect to the leading edge (122). [3] Combustion chamber nozzle (100) according to one of the preceding claims, wherein a center of the outlets (142) of the V-shaped pair of nozzle holes (140) is located in the radially outermost nozzle hole of the multiple nozzle holes (130). [4] Combustion chamber nozzle (100) according to one of the preceding claims, wherein each nozzle hole (140) of the V-shaped pair of nozzle holes (140) is a straight hole with a constant cross-section. [5] Combustion chamber nozzle (100) according to any one of the preceding claims 1-3, wherein each nozzle hole (140) of the V-shaped pair of nozzle holes (140) is a diffuser hole whose cross-section gradually increases towards the outlet (142). [6] Combustion chamber nozzle (100) according to one of the preceding claims, wherein a center of the angle (α) is located in the cavity (112) and two flow paths formed by the outlets (142) of the nozzle holes (140) are separated from each other. [7] Combustion chamber nozzle (100) according to one of the preceding claims, wherein the angle (α) is in a range of 70 to 180 degrees. [8] Combustion chamber nozzle (100) according to one of the preceding claims, wherein the angle (β) formed with respect to the vertical plane above the leading edge (122) is in a range of 20 to 50 degrees. [9] Combustion chamber (1200) for a gas turbine (1000), the combustion chamber comprising: several burners (1220) arranged along an annular combustion chamber housing (1210), each burner (1220) comprising: a combustion chamber nozzle (100) according to one of the preceding claims for injecting fuel for mixing with compressed air; and a cover band (200) that surrounds the combustion chamber nozzle (100) to form an annular space that accommodates the guide vanes (110).

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