Patent Application
20190011129
This application claims priority to and the benefit of Korean Patent Application No. 10-2017-0085080 filed in the Korean Intellectual Property Office on Jul. 4, 2017, the entire contents of which are incorporated herein by reference.
The present invention relates to a fuel nozzle with a turning guide and a gas turbine including the fuel nozzle and the turning guide, and more particularly to the fuel nozzle in which the airflow of compressed air introduced into the fuel nozzle is guided by the turning guide.
A gas turbine is a power engine that generates a hot gas through combustion of a compressed air and a fuel. The gas turbine rotates a turbine with the hot gas. The gas turbine is used for a combined-cycle power generation and a cogeneration.
The gas turbine is roughly divided into a compressor, a combustor, and a turbine. The compressor compresses an incoming air to a high pressure by receiving a part of power generated from a rotation of the turbine. The compressed air is transmitted to the combustor. The combustor mixes and burns the compressed air with the fuel to generate a flow of high-temperature combustion gas and injects it into the turbine. The injected combustion gas rotates the turbine to obtain a rotational force.
Specifically, the air compressed by the compressor flows into the combustor, and the fuel is injected through swirl vanes arranged in each fuel nozzle and is then mixed with the air. A mixture of fuel and air is burned in a combustion chamber located at a downstream of each fuel nozzle assembly, and the combustion gas is discharged through a hot gas path within the turbine.
Meanwhile, it is important to maintain uniform airflow as the compressed air is introduced into the fuel nozzle assembly and as the air is supplied to the fuel nozzles. This uniform flow of air is needed to uniformly mix the air with the fuel. Further, in order to make a stable combustion, it is needed to combust the uniform mixture of the air and fuel.
However, when the compressed air is introduced into the fuel nozzle assembly, the directionality of the airflow is inherently changed. Also, a small region can be created at where the airflow is slowed or the pressure is low, i.e., an air pocket. A region, where the flow rate of air through a fuel nozzle is low, may cause a flame anchoring in the fuel nozzles, thereby damaging fuel nozzle components. In addition, the low flow of air supplied to the fuel nozzle may invite partial changes in the mixture of air and fuel, thus increasing a combustion temperature or creating excessive nitrogen oxides (NOx).
Accordingly, it is an object of the present invention to provide a fuel nozzle in which a turning guide enables a uniform flow of air when compressed air is supplied to the fuel nozzle, thereby preventing creation of an air pocket, to provide the turning guide for the same, and to provide a gas turbine including the fuel nozzle with turning guide.
It is an object of the present invention to provide a fuel nozzle in which a turning guide facilitates a more uniform supply of air into the fuel nozzle, thereby realizing stable combustion and reducing nitrogen oxides, to provide the turning guide for the same, and to provide a gas turbine including the fuel nozzle with turning guide.
According to an embodiment of the present invention, a fuel nozzle may include a central body having an outer wall; a shroud concentrically disposed with respect to the central body and configured to surround the central body while maintaining a space for an air passage between an inner wall of the shroud and the outer wall of the central body; a rim formed on one end of the shroud and forming an air inlet communicating with the air passage; and a turning guide including a turning separator disposed in the air inlet.
The turning separator may have an angle of coverage of the rim in a circumferential direction of 40 to 240 degrees.
The turning guide may further include at least one outer separator connected to a lateral end of the turning separator and extending outwardly from the turning separator in a radial direction, and at least one inner separator connected to a lateral end of the turning separator and extending inwardly from the turning separator in a radial direction. The at least one outer separator may be connected to the lateral end of the turning separator and extending outwardly from the turning separator in the radial direction.
At least one of the turning separator, the inner separator, and the outer separator may have a plurality of openings formed according to a pattern.
A horizontal length of a downstream end of the inner separator and a horizontal length of a downstream end of the outer separator may have a ratio of 4:1 to 1:1.
The turning separator may have at least one opening. The at least one opening may be arranged according to an airflow travel distance.
The turning guide may further include at least one plate-shaped separator connected to a lateral end of the turning separator and extending from the turning separator in a radial direction. The at least one plate-shaped separator may be formed in a streamlined shape.
The outer separator may be tilted at an angle of ±10 degrees in a circumferential direction of the turning separator.
The turning separator may have a lower portion formed to be inclined with respect to one of the central body and the shroud.
The fuel nozzle may further include a plurality of swirl vanes disposed at a specific interval on an outer circumferential surface of the central body, wherein a lower end of the turning guide is spaced apart from an upper end of the plurality of swirl vanes.
According to an embodiment of the present invention, a turning guide may be disposed in the above fuel nozzle and may include a turning separator, disposed in the air inlet and arranged along a circumferential direction of the air inlet, including a lower portion facing an inner wall of the shroud and an upper portion facing an outer surface of the rim.
According to an embodiment of the present invention, a fuel nozzle assembly may comprise a plurality of the above fuel nozzles.
According to an embodiment of the present invention, a gas turbine may include a compressor for compressing incoming air; a combustor for mixing fuel with the compressed air and burning the mixture, the combustor including a combustion chamber and a fuel nozzle assembly disposed in the combustion chamber; and a turbine for generating a turning force by a combustion gas received from the combustor, wherein the fuel nozzle assembly includes a plurality of the above fuel nozzles.
It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood that the present invention is not intended to be limited to embodiments disclosed herein and includes various modifications, equivalents, and/or alternatives of the disclosed embodiments.
Terminology used herein is merely for the purpose of describing particular embodiments and is not intended to limit the invention. Singular forms utilizing “a,” “an,” and “the” are intended to include plural forms unless the context clearly dictates otherwise. In addition, terms such as “comprise,” “include,” and “have” are intended to specify the presence of stated elements, components, operations, functions, features, steps, or the like, without excluding the presence or possibility of additional other elements, components, operations, functions, features, steps, or the like.
The following description of embodiments may omit descriptions of techniques that are well known in the art or not directly related to the present disclosure. This is to clearly convey the subject matter of the present disclosure by omitting unnecessary explanation. For the same reason, some elements in the drawings may be exaggerated, omitted, or schematically illustrated. Also, the size of each element does not entirely reflect the actual size. In the drawings, the same or corresponding elements are denoted by the same reference numerals.
Referring to
Referring to
As shown in
The cap sleeve 220 is disposed inside the casing 210 and formed along the extending direction of the casing 210. The cap sleeve 220 is separated from the inner wall of the casing 210 by an interposed space forming an annular duct 240. The cap sleeve 220 is generally formed in a cylindrical or tapered cylindrical shape, which is, however, exemplary only and not to be construed as a limitation of the present invention.
The end plate 230 is integrated with the casing 210 at one end of the casing 210 to seal the casing 210. Further, the end plate 230 may be combined with a manifold for supplying fuel to a central body 110 of the fuel nozzle 100 and to associated valves and the like. In addition, the end plate 230 supports the plurality of fuel nozzles 100 arranged in the casing 210.
Air compressed in the compressor 10 flows through a passage, i.e., the annular duct 240 between the casing 210 and the cap sleeve 220, and moves along the annular duct 240 until reaching the end plate 230 disposed at the end of the casing 210. Then, the compressed air turns approximately 180 degrees in the opposite direction (i.e., essentially a U-turn) and flows into each fuel nozzle 100.
When the compressed air is thus redirected to enter each fuel nozzle 100, airflow may be slowed inside of a fuel nozzle 100 and thereby an air pocket may be created. It is necessary to prevent this phenomenon.
As shown in
Referring to
A fuel FF (
The shroud 120 is concentric with the central body 110 and extends along the longitudinal direction of the central body 110. The shroud 120 is spaced apart from the central body 110 and is formed to surround the central body 110. Air flows into a space formed between the central body 110 and the shroud 120. Although having any practical shape, the shroud 120 of this embodiment has a cylindrical shape which is concentric with the central body 110. In this case, a cross-section of an air passage 122 formed between the central body 110 and the shroud 120 has an annular shape.
The rim 130 is connected to an entrance of the shroud 120 and is formed along the periphery of the entrance to guide the air to the air passage 122. In order for the compressed air to smoothly enter the fuel nozzle 100 while changing directions, the rim 130 may have a convex curved surface. When each of the central body 110 and the shroud 120 is cylindrical, the rim 130 has an annular shape. An air inlet 131, through which the compressed air flows, is formed by the convex curved surface of the rim 130 and the juxtaposition of the rim 130 and one end of the central body 110.
The turning guide 140, which is shown in detail in
Referring to
When the turning guide 140 distributes the airflows AF2 and AF3, great airflow moment is created in the space between the rim 130 and the turning guide 140. Thus, the distribution of divided airflow can suppress the formation of an air pocket in the vicinity of the shroud 120, which is prone to form in the contemporary art.
A plurality of swirl vanes 124 are disposed on the outer circumferential surface of the central body 110 and are arranged at predetermined intervals around the central body 110. The turning guide 140 is spaced apart from the swirl vanes 124 so as prevent interference between the turning guide 140 and the swirl vanes 124. Specifically, the lower end of the turning guide 140 and the upper end of the swirl vane 124 are spaced apart from each other by a predetermined distance.
As shown in
Specifically, the turning separator 142 may be divided into a lower portion 1421 facing the inner wall of the shroud 120 and an upper portion 1422 facing the outer surface of the rim 130. The lower portion 1421 of the turning separator 142 extends in the same direction as the extending directions of the central body 110 and the shroud 120, is spaced apart from the swirl vane 124, and may be disposed parallel to the inner wall of the shroud 120.
The upper portion 1422 of the turning separator 142 extends in the form of curved surface from the lower portion 1421 along the outer surface of the rim 130. That is, beginning from an upper end of the lower portion 1421, the upper portion 1422 of the turning separator 142 has a convex curved surface to correspond to a portion of the surface of the rim 130. The upper portion 1422 of the turning separator 142 may cover the rim 130 such that the surface facing the rim 130 is spaced apart from the outer surface of the rim 130. Although the upper portion 1422 of the turning separator 142 has an arc shape in this embodiment, this is exemplary only and not to be construed as a limitation of the present invention. Alternatively, the upper portion of the turning separator 142 may have various shapes.
Referring to
In addition, as shown in
If the coverage range of the turning separator 142 is less than 40 degrees, the amount of incoming air divided by the turning separator 142 is small, weakening the airflow distribution effect. On the other hand, if the range of the turning separator 142 is greater than 240 degrees, an undesirable interference of the airflow may occur between neighboring fuel nozzles 100 in the fuel nozzle assembly 100′ in which plural fuel nozzles 100 are annularly arranged. Here, when the fuel nozzles 100 are disposed radially about one fuel nozzle in the fuel nozzle assembly 100′, the turning guide 140 of each fuel nozzle 100 may be disposed at the outermost position of each fuel nozzle 100 in order to minimize interference by adjacent fuel nozzles 100.
Referring to
An inward end of the inner separator 144 may be connected to the outer surface of the central body 110. Although the inner separator 144 is shown as being connected to both lateral ends of the turning separator 142 in this embodiment, this is exemplary only and not to be construed as a limitation. Alternatively, the inner separator 144 may be connected to only one lateral end of the turning separator 142 or to any position of the turning separator 142 other than the lateral ends in the circumferential direction.
When the compressed air flows into the air passage 122 of the fuel nozzle 100, this airflow may be divided by the inner separator 144 in addition to the turning separator 142.
According to another embodiment, as shown in
An outward end of the outer separator 146 may be connected to an inner surface of the shroud 120. Although the outer separator 146 is shown as being connected to both lateral ends of the turning separator 142 in this embodiment, this is exemplary only and not to be construed as a limitation. Alternatively, the outer separator 146 may be connected to only one lateral end of the turning separator 142 or to any position of the turning separator 142 other than the lateral ends in the circumferential direction.
Accordingly, the turning guide 140 of
Meanwhile, the outer separator 146 may be formed at an increased angle with respect to the turning separator 142 in the circumferential direction. That is, as shown in
However, if the outer separator 146 is tilted outwardly at an angle of more than 10 degrees with respect to the turning separator 142, the outer separator 146 may interfere with the flow of the introduced compressed air. This is undesirable.
Alternatively, the outer separator 146 may be formed at a reduced angle with respect to the turning separator 142 in the circumferential direction. That is, as shown in
As above, by adjusting the tilt angle of the outer separator 146 inwardly or outwardly from the turning separator 142, it is possible to finely adjust the airflow.
In addition, as shown in
As above, by adjusting the lower portion 1421 of the inner separator 146 inwardly or outwardly from the central axis of the central body 110, it is possible to adjust the airflow with very effective manner.
The turning guide 140 may include both the inner separator 144 and the outer separator 146. As described above, the inner separator 144 is connected to at least one lateral end of the turning separator 142 and extends inwardly in the radial direction, whereas the outer separator 146 is connected to at least one lateral end of the turning separator 142 and extends outwardly in the radial direction.
The inner separator 144 and the outer separator 146 have a specific length ratio. Specifically, the horizontal length (a) of a downstream end of the inner separator 144 and the horizontal length (c) of a downstream end of the outer separator 146 may have a ratio of 4:1 to 1:1. That is, the horizontal length (a) of the downstream end of the inner separator 144 may be greater than or equal to the horizontal length (c) of the downstream end of the outer separator 146. Therefore, within the passage formed by the outer surface of the central body 110 and the inner surface of the shroud 120, the lower portion of the turning separator 142 is positioned midway in the passage or in the passage closer to the shroud 120.
When the horizontal length (c) of the downstream end of the outer separator 146 is relatively small, a greater amount of air is introduced into the space between the turning guide 140 and the central body 110. On the other hand, when the horizontal length (c) of the downstream end of the outer separator 146 is increased, the amount of air flowing into the space between the turning guide 140 and the shroud 120 increases. If the horizontal length (c) of the downstream end of the outer separator 146 is greater than the horizontal length (a) of the downstream end of the inner separator 144, the amount of the air flowing into the space between the central body 110 and the turning guide 140 is insufficient. This is undesirable because the air is not flowing smoothly.
According to still another embodiment, as shown in
The openings 1422, 1442, and 1462 may be formed in at least one of the turning separator 142, the inner separator 144, and the outer separator 146. That is, the openings may be formed in all three separators as needed, or may be selectively formed only in one or two separators. In addition, the openings may be formed over the entire area of the turning guide 140 without any limitation of their positions.
The openings 1422, 1442, and 1462 arranged in the turning guide 140 may be formed with a specific pattern. For example, as shown in
According to yet another embodiment, as shown in
Normally, the openings 1422, 1442, and 1462 are formed perpendicular to the surface of the corresponding separator. However, as shown in
According to the present invention as described above, when the compressed air flows into the fuel nozzle assembly, it is possible to make the airflow uniform, thereby suppressing the creation of an air pocket. Since the compressed air is more uniformly supplied to the fuel nozzle, the gas can be stably burned, and thereby the generation of nitrogen oxides can be reduced. It is also possible to prevent a local increase of combustion temperature which may result in the generation of a flame inside the fuel nozzle and damage to fuel nozzle components.
While the present disclosure has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken in conjunction with the present disclosure. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the subject matter and scope of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2017-0085080 | Jul 2017 | KR | national |
