Fuel nozzle and combustion chamber and gas turbine containing them

Abstract

Fuel nozzle (2000), which includes: a sheath (2500); an injection cylinder (2100) surrounded by the casing (2500) and configured to supply fuel to a combustion chamber (1240); a swirler (2200) arranged between the injection cylinder (2100) and the casing (2500); and a plurality of perforated discs (2300, 2302, 2303, 2304) arranged downstream of the swirler (2200) to surround an outer peripheral surface of the injection cylinder (2100) to prevent a backlash phenomenon from occurring due to a reduction in pressure around the swirler (2200), wherein the plurality of perforated discs comprise: a first perforated disc (2303) opposite the combustion chamber (1240) and extending from the outer peripheral surface of the injection cylinder (2100) to an inner peripheral surface of the casing (2500); and at least one second perforated disc (2304) spaced from the inner peripheral surface of the casing (2500) by a predetermined distance, and wherein the first perforated disc (2303) and the at least one second perforated disc (2304) each have diameters, the diameters increasing incrementally in the direction of the combustion chamber (1240).

Description

BACKGROUND OF THE INVENTIONField of the invention

[0001] Example embodiments of the present disclosure relate to a fuel nozzle and to a combustor and a gas turbine including the fuel nozzle. Description of the related field

[0002] A gas turbine is a power engine that mixes air compressed in a compressor with fuel for combustion and rotates a turbine using high-temperature gas produced by combustion. The gas turbine is used to power a generator, an aircraft, a ship, a train, and the like.

[0003] A gas turbine typically consists of a compressor, a combustion chamber, and a turbine. The compressor draws in outside air, compresses it, and directs it to the combustion chamber. The compressed air in the compressor is at a high pressure and high temperature. The combustion chamber mixes the compressed air introduced by the compressor with fuel and burns the mixture. The combustion gas produced by the combustion is expelled to the turbine. The combustion gas rotates turbine blades in the turbine, generating power. The generated power is used in various fields, such as generating electrical power and driving machines. [State of the art document]

[0004] Some designs for fuel nozzles that can be used in gas turbines are already known from the state of the art, for example from the patent documents 0001-0009 mentioned below. [Patent Document](Patent Document 0001)

[0005] Korean Patent Application Publication KR 10 2006 0 096 319 A (Title: ONE-PIECE CAN COMBUSTOR) (Patent Document 0002) US 4 587 809 A (Patent Document 0003) US 2009 / 0 145 983 A1 (Patent Document 0004) DE 10 2008 044 448 A1 (Patent Document 0005) JP 2014- 122 723 A (Patent Document 0006) US 6 179 608 B1 (Patent Document 0007) JP 2006- 17 381 A (Patent Document 0008) US 8 234 871 B2 (Patent Document 0009) US 2018 / 0 038 589 A1 SUMMARY OF THE INVENTION

[0006] An object of the present invention is to provide a fuel nozzle that prevents a flashback phenomenon from occurring due to a reduction in pressure around a swirler, and to provide a combustion chamber and a gas turbine incorporating the fuel nozzle.

[0007] Further objects and advantages of the present invention will be understood from the following description and will become apparent from the embodiments of the present invention. Furthermore, it will be apparent to those skilled in the art to which the present invention relates that the objects and advantages of the present invention may be realized by the means claimed and combinations thereof.

[0008] In accordance with one aspect of the present invention, a fuel nozzle includes a jacket; an injection cylinder surrounded by the jacket and configured to supply fuel to a combustion chamber; a swirler disposed between the injection cylinder and the jacket; and a plurality of orifice plates disposed downstream of the swirler to surround an outer peripheral surface of the injection cylinder to prevent a flashback phenomenon from occurring due to a reduction in pressure around the swirler.The plurality of orifice plates comprise: a first orifice plate facing the combustion chamber and extending from the outer peripheral surface of the injection cylinder to an inner peripheral surface of the shroud; and at least one second orifice plate spaced from the inner peripheral surface of the shroud by a predetermined distance, wherein the first orifice plate and the at least one second orifice plate each have diameters, the diameters increasing incrementally toward the combustion chamber.

[0009] A perforated disc may include a disc body for blocking a flame generated in the combustion chamber and a plurality of flow holes formed in the disc body through which the fuel flows.

[0010] Each flow hole may be configured as a straight through-hole aligned with a fuel flow direction or as a diagonal through-hole forming a predetermined angle with a fuel flow direction. Each flow hole may include a bend with at least one inflection point. The plurality of flow holes may have different diameters that increase from an inner peripheral surface of the disk body toward an outer peripheral surface of the disk body.

[0011] The disc body of the at least one second perforated disc has an outer peripheral surface spaced a predetermined distance from an inner peripheral surface of the casing. The distance can be adjusted in accordance with the amount of pressure reduction around the swirler.

[0012] The at least two perforated discs can be arranged such that a flow direction of each of the flow holes of one of the at least two perforated discs is aligned with a flow direction of each of the flow holes of the other perforated discs of the at least two perforated discs; or can be arranged such that a flow direction of each of the flow holes of one of the at least two perforated discs is inclined in a first direction and a flow direction of each of the flow holes of an adjacent perforated disc of the at least two perforated discs is inclined in a second direction opposite to the first direction.

[0013] As previously described, the plurality of orifice plates comprise a first orifice plate facing the combustion chamber, extending from the outer peripheral surface of the injection cylinder to an inner peripheral surface of the shroud; and at least one second orifice plate spaced from the first inner peripheral surface of the shroud by a predetermined distance. The first orifice plate and the at least one second orifice plate each have diameters, with the diameters increasing incrementally toward the combustion chamber.

[0014] In accordance with another aspect of the present disclosure, a combustion chamber of a combustion chamber assembly including a combustion chamber in which fuel is combusted; and a fuel nozzle assembly including a plurality of fuel nozzles for injecting the fuel into the combustion chamber, wherein each of the fuel nozzles of the fuel nozzle assembly corresponds to the fuel nozzle described above.

[0015] In accordance with another aspect of the present disclosure, a gas turbine may include a compressor for compressing air; a combustor for generating a combustion gas by mixing the compressed air with fuel for combustion; and a turbine for generating power using the combustion gas, wherein the combustion chamber of the turbine corresponds to the combustor described above.

[0016] It should be understood that both the foregoing general description and the following detailed description of the present disclosure are exemplary and explanatory and are intended to provide further explanation of the disclosure as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and other objects, features and other advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings in which: Fig. 1 is a perspective sectional view of a gas turbine to which a fuel nozzle in accordance with the present invention may be applied; Fig. 2 is a sectional view of a combustion chamber to which a fuel nozzle in accordance with the present invention may be applied; Fig. 3 is a perspective view of a fuel nozzle module including a plurality of fuel nozzles; Fig. 4 is a partial perspective view of a fuel nozzle having a design not falling within the present invention; Fig. Figure 5 is a plan view of an orifice plate that can be used in a fuel nozzle according to the invention; Fig. 6 to 9 cross-sectional views along line AA' from Fig. 5, each of which represents a modified example of the perforated disc; Fig. 10 is a plan view of an orifice plate that may be used in a fuel nozzle according to the invention; Fig. 11 is a partial perspective view of a fuel nozzle having a design not falling within the present invention; Fig. 12 and Fig. 13 cross-sectional side views are modified examples of the Fig. 11, but can also be applied to at least one of the at least two perforated discs shown in Fig. 14 are shown; and Fig. 14 is a partial perspective view of a fuel nozzle in accordance with the present invention. DESCRIPTION OF SPECIFIC EMBODIMENTS

[0018] A fuel nozzle and combustor, and a gas turbine incorporating the same, in accordance with exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. However, the present disclosure may be embodied in other forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art. Like reference characters refer to like parts throughout the various figures and embodiments of the present disclosure.

[0019] When a component is referred to as "comprising or containing" any component, this does not, of course, exclude other components, but, unless otherwise specified, may further comprise or contain the other components. Furthermore, as used herein, a spatially relative term "on" does not necessarily mean that an element is located on top of another element in the direction of gravity, but rather means that the element is located on top of or below another element.

[0020] Fig. 1 illustrates an interior of a gas turbine 1000 including a combustion chamber 1200 to which a fuel nozzle in accordance with the present invention may be applied, and Fig. 2 shows an example of the combustion chamber 1200 Fig. 1. Fig. 3 shows a fuel nozzle module containing several fuel nozzles, of which one fuel nozzle is in Fig. 4 is shown in detail.

[0021] Based on Fig. 1, the gas turbine 1000 may include a compressor 1100 that compresses the introduced gas to a high pressure, a combustion chamber 1200 that mixes the compressed air supplied by the compressor 1100 with fuel and combusts the mixture, and a turbine 1300 that generates rotational force using combustion gas generated in the combustion chamber. In this specification, the inlet and outlet sides are defined based on the flow direction of fuel or air.

[0022] The thermodynamic cycle of the gas turbine can ideally follow a Brayton cycle. The Brayton cycle consists of four phases, including isentropic compression (adiabatic compression), isobaric heat input, isentropic expansion (adiabatic expansion), and isobaric heat output. In other words, in the Brayton cycle, heat energy is released by combustion of fuel in an isobaric environment after the atmospheric air is sucked in and compressed to a high pressure, hot combustion gas is allowed to expand to be converted into kinetic energy, and then exhaust gas with residual energy is discharged to the atmosphere. The Brayton cycle consists of four processes, i.e., compression, heating, expansion, and discharge. The present invention can be applied to a gas turbine having the same or a similar configuration as the one exemplified in Fig. 1 can be widely applied.

[0023] The gas turbine's compressor 1100 is used to draw in and compress air, primarily serving to supply cooling air to a high-temperature region, which is required for cooling within the gas turbine, while supplying combustion air to the combustor 1200. As the air drawn into the compressor 1100 undergoes an adiabatic compression process, the pressure and temperature of the air passing through the compressor 1100 increase.

[0024] Typically, the compressor 1100 of the gas turbine can be designed as a centrifugal compressor or as an axial compressor. Generally, the centrifugal compressor is applied to a small gas turbine, while a multi-stage axial compressor is applied to a large gas turbine 1000, as shown in Fig. 1, since it is necessary to compress a large amount of air.

[0025] The compressor 1100 is driven using a portion of the power output from the turbine 1300. For this purpose, the rotating shaft (not shown) of the compressor 1100 is directly connected to the rotating shaft of the turbine 1300.

[0026] Combustion chamber 1200 mixes the compressed air supplied from the outlet of compressor 1100 with fuel for isobaric combustion to produce high-energy combustion gas. Combustion chamber 1200 is located downstream of compressor 1100 and includes a plurality of burner modules 1210 arranged annularly around gas turbine 1000.

[0027] Based on Fig. 2, each of the burner modules 1210 can be Fig. 1 includes a combustion chamber assembly 1220 including a combustion chamber 1240 in which fuel is combusted, and a fuel nozzle assembly 1230 including a plurality of fuel nozzles that inject fuel into the combustion chamber 1240.

[0028] The gas turbine may contain gaseous fuel, liquid fuel, or a gas-liquid composite fuel, and the fuel in the present invention contains any of these. It is important to create a combustion environment for reducing emissions such as carbon monoxide or nitrogen oxide, which is subject to regulatory requirements. Accordingly, despite the relative difficulty of controlling such combustion, premixed combustion has been increasingly used in recent years because it can achieve uniform combustion to reduce emissions by lowering the combustion temperature.

[0029] In premixed combustion, the compressed air supplied by the compressor 1100 is mixed with fuel in the fuel nozzle assembly 1230 and then introduced into the combustion chamber 1240. When combustion is stable after the premixed gas is initially ignited by an igniter, combustion is maintained by the supply of fuel and air.

[0030] The fuel nozzle assembly 1230 includes a plurality of fuel nozzles 2000 that inject fuel, and the fuel supplied by the fuel nozzles 2000 is mixed with air at a rate suitable for combustion. As shown in Fig. 3, the fuel nozzles 2000 (to be described later) may be configured such that a plurality of outer fuel nozzles are arranged radially around an inner fuel nozzle.

[0031] Again based on Fig. 2, the combustion chamber assembly 1220 includes the combustion chamber 1240 as a space in which combustion is carried out, and includes a liner 1250 and a transition piece 1260.

[0032] The liner 1250 is arranged downstream of the fuel nozzle assembly 1230 and may have a dual structure formed by an inner liner 1251 and an outer liner 1252 surrounding the inner liner 1251. Here, the inner liner 1251 is a hollow tubular element that forms the combustion chamber 1240. The inner liner 1251 may be cooled by the compressed air passing through an annular space within the outer liner 1252.

[0033] The transition piece 1260 is arranged downstream of the liner 1250, and the combustion gas generated in the combustion chamber 1240 can be exhausted from the transition piece 1260 to the turbine 1300. The transition piece 1260 can have a dual structure formed by an inner transition piece 1261 and an outer transition piece 1262 surrounding the inner transition piece 1261. The inner transition piece 1261, similar to the inner liner 1251, is a hollow tubular member and can have a diameter that gradually decreases from the liner 1250 to the turbine 1300. In this case, the inner liner 1251 can be coupled to the inner transition piece 1261 by a leaf spring seal (not shown). Since the ends of the inner lining 1251 and the inner transition piece 1261 are at the combustion chamber 1200 andattached to the turbine 1300, the leaf spring seal must have a structure that can adapt to the longitudinal and diametrical elongation due to thermal expansion in order to support the inner liner 1251 and the inner transition piece 1261.

[0034] The combustion chamber 1200 has a structure in which the outer liner 1252 and the outer transition piece 1262 surround the inner liner 1251 and the inner transition piece 1261, respectively. Compressed air can pass through the annular space between the inner liner 1251 and the outer liner 1252 and the annular space between the inner transition piece 1261 and the outer transition piece 1262. The inner liner 1251 and the inner transition piece 1261 can be cooled by the compressed air passing through these annular spaces.

[0035] The high-temperature and high-pressure combustion gas generated in the combustor 1200 is supplied to the turbine 1300 through the liner 1250 and the transition piece 1260. In the turbine 1300, the thermal energy of the combustion gas is converted into mechanical energy by exerting an impact and reaction force on a plurality of blades radially arranged on the rotating shaft of the turbine 1300 through the adiabatic expansion of the combustion gas to rotate a rotating shaft. Part of the mechanical energy obtained by the turbine 1300 is supplied as energy required for compressing air in the compressor, and the remainder is used as useful energy required to drive a generator to generate electrical power or the like.

[0036] A fuel nozzle 2000 according to the embodiment of the present invention will be described below with reference to the accompanying drawings.

[0037] Based on Fig. 3, a fuel nozzle module includes a plurality of fuel nozzles 2000, each of which includes an injection cylinder 2100, swirler 2200, a perforated disc 2300 and a shroud 2500.

[0038] The injection cylinder 2100 is a means for supplying fuel and premixing fuel and air, and extends in one direction. Typically, the injection cylinder 2100 has a cylindrical shape, but the fuel nozzle according to the invention is not limited to a fuel nozzle with a cylindrical shape.

[0039] Based on Fig. 4, it can be seen that the injection cylinder 2100 defines a space for mixing fuel and air, wherein the fuel and air can be mixed with each other as they pass longitudinally through the injection cylinder 2100. The injection cylinder 2100 may include an air inlet port 2110 through which air is introduced into the injection cylinder 2100, and an exhaust port 2120 through which a mixture of air and fuel is exhausted. The exhaust port 2120 is formed at an outlet end of the injection cylinder 2100 and is exemplified by an exhaust port 2120 formed at the bottom of the cylindrical injection cylinder 2100.

[0040] Again based on Fig. 2, a head end plate 1231 is coupled to the end of a nozzle housing 1232, which forms the outer wall of the fuel nozzle assembly 1230, to seal the nozzle housing 1232, and may be coupled to a manifold, an associated valve, or the like to supply fuel to the injection cylinder 2100. The head end plate 1231 supports the fuel nozzle 2000 arranged in the nozzle housing 1232. The fuel nozzle 2000 is connected to the nozzle flange 2400 ( Fig. 3), which is arranged at one end of the injection cylinder 2100, is fixed to the head end plate 1231.

[0041] Fuel is introduced through a fuel injector (not shown) and through the head end plate 1231 and flows longitudinally along the injection cylinder 2100 of the fuel nozzle 2000 to be injected into the combustion chamber 1240.

[0042] The casing 2500 surrounds the injection cylinder 2100 and extends in the same longitudinal direction as the injection cylinder 2100. Specifically, the casing 2500 is spaced from an outer peripheral surface of the injection cylinder 2100 to form a passage for fuel and air to pass through. Since the casing 2500 is arranged on the same axis as the injection cylinder 2100 and is spaced from the injection cylinder 2100 by a certain distance to surround the injection cylinder 2100, a cylindrical casing 2500 is exemplified. In this case, the passage formed by the injection cylinder 2100 and the casing 2500 may have an annular cross-section.

[0043] The swirlers 2200 are arranged radially on the outer peripheral surface of the injection cylinder 2100 so as to be arranged approximately longitudinally in the center of the cylinder, thereby creating a swirling flow of the fuel introduced into the space between the jacket 2500 and the injection cylinder 2100. The swirlers 2200 may each have an internal passage communicating with the interior of the injection cylinder 2100. The fuel introduced into the injection cylinder 2100 may be discharged via the communication passages in the swirlers through outlets 2210 penetrating the interior and exterior of the swirlers 2200.

[0044] Fig. 4 shows a fuel nozzle which differs from the fuel nozzle according to the invention only in that there is only one perforated disc instead of several perforated discs with different diameters which increase incrementally towards the combustion chamber. Fig. 5 represents a perforated disc in the fuel nozzle Fig. 4. Fig. 6 to 10 show various modified examples of the perforated disc. The various embodiments of the perforated disc can be applied to at least one of at least two perforated discs in the fuel nozzle according to the invention, which are shown for example in Fig. 14 is shown.

[0045] In a conventional fuel nozzle, a swirling flow is generated as fuel passes through swirlers, and the pressure around the swirlers is reduced by the swirling flow. This reduced pressure causes a flashback phenomenon, in which the flame generated in a combustion chamber flows back toward the fuel nozzle. This flashback phenomenon leads to the deterioration of the fuel nozzle. The fuel nozzle 2000 includes the orifice plate 2300 installed downstream of the swirlers 2200 to prevent a flashback phenomenon caused by a reduction in pressure around the swirlers 2200.

[0046] The orifice plate 2300 includes a plate body 2310 that prevents the flame generated in the combustion chamber 1240 from flowing back into the fuel nozzle. The plate body 2310 is formed as a flat plate shape with an inner and an outer peripheral surface and includes two opposing surfaces, each of which is perpendicular to the direction of fuel flow through the channel between the shroud 2500 and the injection cylinder 2100. The orifice plate 2300 may include a plurality of flow holes 2320, each of which has a predetermined size (diameter) and shape (configuration) to prevent the flow of fuel from being interrupted.

[0047] The orifice plate 2300 may be formed from the outer peripheral surface of the injection cylinder 2100 to the inner peripheral surface of the casing 2500. The orifice plate 2300 may be formed such that it abuts the inner peripheral surface of the casing 2500. For example, the orifice plate 2300 may be spaced a predetermined distance from the inner peripheral surface of the casing 2500. This distance may be adjusted in accordance with the amount of pressure reduction around the swirlers 2200. That is, since there is a high possibility of backlash in the case of larger amounts of pressure reduction around the swirlers 2200, the distance between the orifice plate 2300 and the inner peripheral surface of the swirler 2500 may be reduced, while conversely, the distance may be increased for smaller amounts.

[0048] The flow holes 2320 can be as in Fig. 5. The plurality of flow holes 2320 may extend in a pattern over the entire surface of the orifice plate 2300, ie, from the outer peripheral surface of the injection cylinder 2100 to the inner peripheral surface of the casing 2500. As shown in Fig. As shown in Figure 6, each of the flow holes 2320a may be configured as a straight through-hole that is perpendicular to the flat surfaces of the disk body 2310 and thus aligned with the fuel flow direction. Forming each of the flow holes 2320a as a straight through-hole imparts linearity to the flow of fuel introduced into the space between the shroud 2500 and the injection cylinder 2100, thus enabling a smooth fuel flow.

[0049] As in Fig. As shown in Figure 7, each of the flow holes 2320b may alternatively be configured as a diagonal through-hole that is inclined with respect to the flat surfaces of the disk body 2310 and thus forms a predetermined angle with the flow direction of the fuel. Forming each of the flow holes 2320b as a diagonal through-hole imparts a spiral swirling effect to the fuel introduced into the space between the shroud 2500 and the injection cylinder 2100, thus enabling uniform mixing of the fuel. The predetermined angle of one through-hole of the flow holes 2320b may be different from the predetermined angle of another through-hole of the flow holes 2320b, and the flow holes 2320 may include an array of both diagonal through-holes and straight through-holes.The predetermined angle of one through-hole of the flow holes 2320b may be different from the predetermined angle of another through-hole of the flow holes 2320b. The predetermined angle of the through-holes of the flow holes 2320b may be as shown in FIG. Fig. 7 may be consistent over the entire disk body 2310, or the predetermined angle of a through-hole or group of through-holes of the flow holes 2320b may be different from the predetermined angle of another through-hole or group of through-holes of the flow holes 2320b. For example, each of the flow holes 2320c may be as in the disk body 2310 of Fig. 8 may be formed in such a way that the imaginary extension lines of one group of through holes of the flow holes 2320c intersect the imaginary extension lines of another group. Furthermore, the flow holes 2320 may comprise an arrangement of both diagonal through holes ( Fig. 7) as well as straight through holes ( Fig. 6) are included.

[0050] As in Fig. 9, each of the flow holes 2320d may alternatively include a bend with at least one inflection point t. In this case, the overall directional bundling of the flow holes 2320d containing the bend may be configured as one of Fig. 6 to 8. That is, the relative position of the inlet and outlet sides of the flow holes 2320d may be aligned with each other, similar to the perpendicular configuration of the flow holes 2320b; or their relative positions may be offset from each other, similar to the inclined configuration of the flow holes 2320b or 2320c. When the flow holes 2320d are configured as a curved through-hole having at least one inflection point t, the direction of the fuel introduced into the flow hole 2320d (inlet side) is switched to flow in a reverse direction after the inflection point t. Thus, it is possible to uniformly mix the fuel by imparting a spiral swirling effect to the fuel.

[0051] In addition, the flow holes 2320 can be made of Fig. 5, which serve as the flow holes of one of Fig. 6 to 9, have different diameters. As shown in Fig. 10, the plurality of flow holes 2320e may be configured, for example, to have diameters that increase from the inner peripheral surface of the disk body 2310 toward the outer peripheral surface of the disk body 2310. Such a structure can guide the flow of fuel to increase toward the outer peripheral surface of the hole disk 2300.

[0052] Although the flow holes 2320 in Fig. 5 to 10 are shown as radial for convenience of description, they may instead be arranged in a rectilinear or arbitrary direction or arranged at arbitrary positions in accordance with an amorphous pattern.

[0053] The following is based on Fig. 11, a fuel nozzle 2000 is described in accordance with another embodiment not falling within the scope of the present invention. In this embodiment, each of the fuel nozzles of the fuel nozzle module ( Fig. 3) an injection cylinder 2100, swirler 2200, a nozzle flange 2400, and a shroud 2500. In the embodiment of Fig. 11, the structure and function of the injection cylinder 2100, the swirler 2200, the nozzle flange 2400, and the shroud 2500 are consistent with those of the above-described embodiment, and their detailed description is omitted.

[0054] As in Fig. As shown in Figure 11, the fuel nozzle 2000 includes a plurality of orifice plates 2302 arranged in the space between the shroud 2500 and the injection cylinder 2100 and spaced apart by a predetermined distance. These orifice plates 2302 include at least one of the orifice plates 2300 modified in accordance with the above-described embodiment, that is, a orifice plate in accordance with one of Fig. 6 to 10. In the present embodiment, at least two perforated disks 2302 may be formed from the outer peripheral surface of the injection cylinder 2100 to the inner peripheral surface of the casing 2500.

[0055] As in Fig. As shown in Figure 12, a plurality of perforated discs 2302 are formed, each having flow holes 2320. In this case, the arrangement of the perforated discs 2302 is regularly repeated from one disc to the next. When the perforated discs 2302 are arranged such that each of the flow holes 2320 is aligned with the fuel flow direction, it is possible to achieve a smooth air flow by imparting repeated linearity to the fuel introduced into the space between the jacket 2500 and the injection cylinder 2100.

[0056] As in Fig. As shown in Figure 13, a plurality of perforated discs 2302 are formed, each having flow holes 2320. In this case, the arrangement of the perforated discs 2302 is varied from one disc to the next. When the perforated discs 2302 are arranged such that each of the flow holes 2320 is alternately inclined to form a series of predetermined opposite angles to the fuel flow direction, it is possible to more evenly mix the fuel introduced into the space between the jacket 2500 and the injection cylinder 2100 by imparting a repeated swirling action.

[0057] The fuel nozzles 2000 from Fig. 11 to 13 each include a plurality of perforated discs 2302. Thus, even if a perforated disc 2302a facing the combustion chamber 1240 is damaged due to a kickback phenomenon, the kickback phenomenon can be prevented by a next perforated disc 2302b.

[0058] The following is based on Fig. 14, a fuel nozzle 2000 in accordance with the present invention is described. Each of the fuel nozzles of the fuel nozzle module ( Fig. 3) includes an injection cylinder 2100, swirler 2200, a nozzle flange 2400 and a shroud 2500. In the embodiment of Fig. 14, the structure and function of the injection cylinder 2100, the swirler 2200, the nozzle flange 2400, and the shroud 2500 are consistent with those of the above-described embodiment, and their detailed description is omitted.

[0059] As in Fig. 14, the fuel nozzle 2000 in accordance with the embodiment of the present invention includes a plurality of orifice plates 2303 and 2304, each provided in successive stages along the length in the longitudinal direction of the injection cylinder 2100. These orifice plates 2303 and 2304 include at least one of the orifice plates 2300, which is smaller than the embodiment described above, ie, compared to the orifice plate in accordance with one of Fig.6 to 11. In the embodiment of the present invention, a first orifice plate 2303, which faces the combustion chamber 1240, extends from the outer peripheral surface of the injection cylinder 2100 to the inner peripheral surface of the shroud 2500, and second orifice plates 2304, which are arranged behind the first orifice plate 2303, are each spaced a predetermined distance from the inner peripheral surface of the shroud 2500. Generally, the second orifice plates 2304 each have diameters that gradually increase toward the combustion chamber 1240. Moreover, since the first orifice plate 2303 may have the largest diameter, the incremental increase in diameters toward the combustion chamber 1240 is effected for all of the first and second orifice plates 2303 and 2304.

[0060] Since the first and second orifice plates 2303 and 2304 have diameters that gradually increase toward the combustion chamber 1240, it is possible to achieve smooth flow by ensuring a flow passage for the fuel introduced into the space between the shroud 2500 and the injection cylinder 2100. Thus, even if the first orifice plate 2303 facing the combustion chamber 1240 is damaged due to a backlash phenomenon, it is possible to prevent the backlash phenomenon by using one or more of the subsequent (second) orifice plates 2304.That is, assuming their function has not been effectively destroyed, the backfire may be partially prevented by the first orifice plate 2303. In this case, the second orifice plates 2304 may prevent the backfire, which may traverse a damaged portion of the first orifice plate 2303, from reaching the fuel nozzle. In this case, the one or more of the second orifice plates 2304 may not fully extend the distance between the shroud 2500 and the injection cylinder 2100.

[0061] In summary, by installing multiple perforated discs on the outlet side of the swirler, it is possible to prevent backflow due to a reduction in pressure around the swirler. Furthermore, by creating differently configured flow holes in a perforated disc, it is possible to impart a linear or swirling effect to the fuel flow passing through the fuel nozzle.

[0062] Although the present disclosure has been described with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the disclosure as defined in the following claims.

Claims

[1] Fuel nozzle (2000) comprising the following: a casing (2500); an injection cylinder (2100) surrounded by the casing (2500) and configured to supply fuel to a combustion chamber (1240); a swirler (2200) arranged between the injection cylinder (2100) and the casing (2500); and several perforated discs (2300, 2302, 2303, 2304) arranged on the outlet side of the swirl plate (2200) to surround an outer circumferential surface of the injection cylinder (2100) to prevent backflow due to a reduction in pressure around the swirl plate (2200), including the multiple perforated discs: a first perforated disc (2303) opposite the combustion chamber (1240) and extending from the outer circumferential surface of the injection cylinder (2100) to an inner circumferential surface of the casing (2500); and at least a second perforated disk (2304) which is spaced apart from the inner circumferential surface of the casing (2500) by a predetermined distance, and wherein the first perforated disk (2303) and the at least one second perforated disk (2304) each have diameters, the diameters increasing incrementally in the direction of the combustion chamber (1240). [2] Fuel nozzle (2000) according to claim 1, wherein at least one of the several perforated disks comprises a disk body (2310) to block a flame generated in the combustion chamber (1240) and several flow holes (2320) formed in the disk body (2310) through which the fuel flows. [3] Fuel nozzle (2000) according to claim 2, wherein each flow hole (2320) is configured as a straight through hole (2320a) that is aligned with a flow direction of the fuel. [4] Fuel nozzle (2000) according to claim 2, wherein each flow hole (2320) is configured as a diagonal through hole (2320b, 2320c) forming a predetermined angle with a flow direction of the fuel. [5] Fuel nozzle (2000) according to claim 2, wherein each flow hole (2320) contains a bend (2320d) with at least one inflection point. [6] Fuel nozzle (2000) according to any one of claims 2 to 5, wherein the multiple flow holes (2320) have different diameters (2320e). [7] Fuel nozzle (2000) according to claim 6, wherein the different diameters (2320e) of the multiple flow holes increase from an inner circumferential surface of the disk body (2310) towards an outer circumferential surface of the disk body (2310). [8] Fuel nozzle (2000) according to any one of claims 2 to 7, wherein the at least one second perforated disk (2304) has a disk body (2310) with an outer circumferential surface which is spaced apart from an inner circumferential surface of the casing (2500) by a predetermined distance, wherein the predetermined distance is adapted in accordance with an amount of pressure reduction around the turbulator (2200). [9] Fuel nozzle (2000) according to claim 1, wherein each of the at least two perforated disks (2303, 2304) comprises a disk body (2310) and several flow holes (2320) formed in the disk body (2310) through which the fuel flows, wherein each flow hole (2320) is configured as a straight through-hole (2320a) oriented towards a flow direction of the fuel, and wherein the at least two perforated disks (2303, 2304) are arranged in such a way that a flow direction of each of the flow holes (2320a) of one of the at least two perforated disks (2303) is aligned with a flow direction of each of the flow holes (2320a) of the other perforated disks of the at least two perforated disks. [10] Fuel nozzle (2000) according to claim 1, wherein each of the at least two perforated disks (2303, 2304) comprises a disk body (2310) and several flow holes (2320) formed in the disk body (2310) through which the fuel flows, wherein each flow hole (2320) is configured as a diagonal through-hole (2320b) forming a predetermined angle with a flow direction of the fuel, and wherein the at least two perforated disks (2303, 2304) are arranged such that a flow direction of each of the flow holes (2320b) of one of the at least two perforated disks (2303) is inclined in a first direction and that a flow direction of each of the flow holes (2320c) of an adjacent perforated disk of the at least two perforated disks is inclined in a second direction, which is opposite to the first direction.

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