Turbine exhaust gas recirculation mixer box

Abstract

In a closed system that recirculates exhaust gas from a gas turbine engine (100), recirculated exhaust gas (255) should be mixed into intake air (215) in a manner that produces a uniform distribution within the mixed gas (305) while preventing excessive pressure drop at the mixing point and not requiring an excessive conduit length. Otherwise, the performance of the gas turbine engine may be adversely affected. Thus, a mixer box (300) is disclosed that injects recirculated exhaust gas into the flow path of intake air in a uniform manner. The mixer box includes a mixer (400) extending a flow path of recirculated exhaust gas into a flow path of intake air along two axes. Each mixer includes a surface hole (422, 432) and an internal passage designed to facilitate uniform injection of recirculated exhaust gas from the mixer into the flow path of the intake air.

Description

Technical Field

[0001] The embodiments described herein relate generally to recirculation of exhaust gas from a turbine, and more particularly to a mixer box for mixing exhaust gas from a turbine of a gas turbine engine with intake air to a compressor of the gas turbine engine. Background Art

[0002] In a closed system including a gas turbine engine, exhaust gas from a turbine of the gas turbine engine is recirculated through the system. In particular, the exhaust gas may be mixed with intake air (e.g., fresh outside air) supplied to a compressor of the gas turbine engine. The exhaust gas and intake air will differ in various characteristics, including temperature, humidity, oxygen (O2) level, carbon dioxide (CO2) level, and / or the like. Additionally, the volume of the exhaust gas and the volume of the intake air may differ in percentage of the total gas at the mixing point.

[0003] It is important that the two fluids mix with a minimum of pressure drop. Excessive pressure drop at the mixing point will result in back pressure which will be detrimental to the performance of the gas turbine engine.

[0004] Ideally, the mixing mechanism should mix the exhaust gas with the intake air to an acceptable level of uniformity at the inlet of the compressor while not having a deleterious aerodynamic effect on the performance of the gas turbine engine. In many cases, the available duct length for mixing the exhaust and intake flows may be limited, in which case the mixing mechanism must be able to achieve an acceptable level of uniformity despite the limited available duct length.

[0005] The present invention is directed to overcoming one or more problems discovered by the inventors. Summary of the invention

[0006] In an embodiment, a mixer box includes: a first conduit, the first conduit including an upstream end and a downstream end along a first axis, the upstream end and the downstream end are both open to form a first flow path through the first conduit along the first axis; a first side and a second side along a second axis perpendicular to the first axis, the first side including one or more openings; and one or more mixers, each of the mixers extending along the first axis between the upstream end and the downstream end, and extending along the second axis between the first side and the second side, so that the second flow path is divided into a plurality of channels, wherein each of the one or more mixers has an open end at the first side, the open end is aligned with one of the one or more openings in the first side, so that a second flow path perpendicular to the first flow path is formed to pass through the first side into a hollow interior of the mixer, wherein each of the one or more mixers includes two side surfaces, each of the two side surfaces includes a plurality of holes, each of the holes forming a flow path between the hollow interior of the mixer and one of the plurality of channels.

[0007] In an embodiment, a system includes: an air inlet; a gas turbine engine; an exhaust gas recirculation system; and a mixer box, the mixer box including a first duct, the first duct including an upstream end and a downstream end along a first axis, the upstream end and the downstream end are both open to form a first flow path through the first duct along the first axis, the first flow path is in fluid communication with an output of the air inlet on the upstream end and an inlet of the gas turbine engine on the downstream end, a first side and a second side along a second axis perpendicular to the first axis, the first side including one or more openings, and one or more mixers, the mixers each extending between the upstream end and the downstream end along the first axis and along the second axis Extending between the first side and the second side so that the first flow path is divided into a plurality of channels, wherein each of the one or more mixers has an open end at the first side, the open end being aligned with one of the one or more openings in the first side so that a second flow path perpendicular to the first flow path is formed through the first side into the hollow interior of the mixer, each second flow path being in communication with an output fluid of the exhaust gas recirculation system, wherein each of the one or more mixers includes two side surfaces, each of the two side surfaces including a plurality of holes, each of the holes forming a flow path between the hollow interior of the mixer and one of the plurality of channels.

[0008] In an embodiment, a mixer box includes: a first duct including an upstream end and a downstream end along a first axis, the upstream end and the downstream end are both open to form a first flow path passing through the first duct along the first axis, a first side along a second axis perpendicular to the first axis and a second side, the first side including a plurality of openings, and a plurality of mixers, the mixers each extending between the upstream end and the downstream end along the first axis and extending between the first side and the second side along the second axis so that the first flow path is divided into a plurality of channels, wherein each of the plurality of mixers has an open end at the first side, the open end being aligned with one of the plurality of openings in the first side so that a second flow path perpendicular to the first flow path is formed to pass through the first side into a hollow interior of the mixer, wherein each of the plurality of mixers includes two side surfaces, the two side surfaces Each side surface of the surface includes a plurality of holes, each of which forms a flow path between the hollow interior of the mixer and one of the plurality of channels, the plurality of holes are arranged in a two-dimensional manner along the first axis and the second axis in each of the two side surfaces of each of the plurality of mixers, and the area of ​​the holes decreases as the distance from the open end of the mixer increases, wherein each of the plurality of mixers includes a rear surface, the rear surface includes a plurality of holes, each of which forms a flow path between the hollow interior of the mixer and the exterior of the mixer, the area of ​​the plurality of holes in each rear surface of each of the plurality of mixers decreases as the distance from the open end of the mixer increases, and wherein each of the plurality of mixers includes one or more baffles, each of which extends along the second axis so that the hollow interior of the mixer is divided into a plurality of channels along the second axis. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Details of embodiments of the invention, both as to their structure and operation, may be gleaned in part by studying the accompanying drawings, in which like reference numerals refer to like parts, and in which:

[0010] Figure 1 shows a schematic diagram of a gas turbine engine according to an embodiment;

[0011] Figure 2 A block diagram of an exemplary closed system including a gas turbine engine according to an embodiment is shown;

[0012] Figure 3 shows a perspective view of a mixer box according to an embodiment;

[0013] Figure 4 shows a cross-sectional perspective view of a mixer box according to an embodiment;

[0014] Figure 5shows a cross-sectional perspective view of a mixer box according to an embodiment;

[0015] Figure 6 shows a perspective view of a single mixer according to an embodiment;

[0016] Figure 7 shows a perspective view of the front surface of an isolated mixer according to an embodiment;

[0017] Figure 8 shows a perspective view of a rear surface of an isolated mixer according to an embodiment;

[0018] Fig. 9 shows a front view of a side surface of an isolated mixer according to an embodiment;

[0019] Fig.10 shows a perspective view of a base plate of an isolated mixer according to an embodiment;

[0020] Fig.11 A perspective view showing a baffle of an isolated mixer according to an embodiment;

[0021] Fig.12 A perspective view showing the piping of an isolated mixer box according to an embodiment;

[0022] Fig.13 A perspective view showing a flow shroud of an isolated mixer box according to an embodiment;

[0023] Fig.14 shows an outline of a mixer box according to an embodiment; and

[0024] Fig.15 A perspective cross-sectional view of a portion of a closed system with a mixer box installed is shown according to an embodiment. DETAILED DESCRIPTION

[0025] The detailed description set forth below in conjunction with the accompanying drawings is intended as a description of various embodiments, rather than being intended to represent the only embodiments in which the present invention may be practiced. The detailed description includes specific details for providing a thorough understanding of the embodiments. However, it will be apparent to those skilled in the art that embodiments of the present invention may be practiced without these specific details. In some cases, known structures and components are shown in simplified form for brevity of description.

[0026] For clarity and ease of explanation, some surfaces and details may be omitted in this specification and the accompanying drawings. In addition, unless otherwise specified, the "upstream" and "downstream" or "forward" and "rearward" mentioned herein are relative to the flow direction of the main gas (e.g., air) used in the combustion process. It should be understood that "upstream", "forward" and "front" refer to a position closer to the main gas source or a direction toward the main gas source, while "downstream", "rearward" and "rear" refer to a position farther away from the main gas source or a direction away from the main gas source. Therefore, the trailing edge or end of a component (e.g., a turbine blade) is located downstream of the leading edge or end of the same component. In addition, it should be understood that, as used herein, the terms "side", "top", "bottom", "front", "rear", "above", "below", etc. are used to facilitate understanding to convey the relative positions of various components relative to each other, and do not imply any specific orientation of those components in absolute terms (e.g., relative to the external environment or the ground).

[0027] It should also be understood that the various components shown herein are not necessarily drawn to scale. In other words, the features disclosed in the various embodiments may be implemented using relative dimensions within and between components that are different from those shown in the drawings.

[0028] Figure 1 A schematic diagram of a gas turbine engine 100 according to an embodiment is shown. The gas turbine engine 100 includes a shaft 102 having a central longitudinal axis L. Various other components of the gas turbine engine 100 are concentric with the longitudinal axis L and may be annular relative to the longitudinal axis L. A radial axis may refer to any axis or direction radiating outward from the longitudinal axis L at an angle substantially orthogonal to the longitudinal axis L, such as Figure 1 Thus, the term "radially outward" should be understood to mean away from or away from the longitudinal axis L, and the term "radially inward" should be understood to mean close to or toward the longitudinal axis L. As used herein, the term "radial" refers to any axis or direction substantially perpendicular to the longitudinal axis L, and the term "axial" refers to any axis or direction substantially parallel to the longitudinal axis L.

[0029] In an embodiment, the gas turbine engine 100 includes an inlet 110, a compressor 120, a combustor 130, a turbine 140, and an exhaust outlet 150 from the upstream end to the downstream end. In addition, the downstream end of the gas turbine engine 100 may include a power output coupling 104. One or more of these components of the gas turbine engine 100 (possibly including all) may be made of stainless steel and / or a durable high-temperature material called a "superalloy". Superalloys are alloys that exhibit excellent mechanical strength and creep resistance, good surface stability, and corrosion resistance and oxidation resistance at high temperatures. Examples of superalloys include, but are not limited to, Hastelloy, Inconel, Waspaloy, Rene alloy, Haynes alloy, Incoloy, MP98T, TMS alloy, CMSX alloy, and CMSX single crystal alloy.

[0030] The inlet 110 may funnel a working fluid F (e.g., a primary gas, such as air) into an annular flow path 112 about the longitudinal axis L. The working fluid F flows through the inlet 110 into the compressor 120. Although the working fluid F is shown as flowing into the inlet 110 from a particular direction and at an angle substantially perpendicular to the longitudinal axis L, it should be understood that the inlet 110 may be configured to receive the working fluid F from any direction and at any angle suitable for a particular application of the gas turbine engine 100. Although the working fluid F will be primarily described herein as air, it should be understood that the working fluid F may include other fluids, including other gases.

[0031] The compressor 120 may include a series of compressor rotor assemblies 122 and stator assemblies 124. Each compressor rotor assembly 122 may include a rotor disk that is circumferentially filled with a plurality of rotor blades. The rotor blades in the rotor disk are separated from the rotor blades in the adjacent disk along the axial axis by the stator assembly 124. The compressor 120 compresses the working fluid F through a series of stages corresponding to each compressor rotor assembly 122. The compressed working fluid F then flows from the compressor 120 into the combustor 130.

[0032] The combustor 130 may include a combustor casing 132 housing one or more and typically a plurality of fuel injectors 134. In embodiments having a plurality of fuel injectors 134, the fuel injectors 134 may be arranged circumferentially within the combustor casing 132 at equally spaced intervals about the longitudinal axis L. The combustor casing 132 diffuses the working fluid F, and the fuel injectors 134 inject fuel into the working fluid F. The injected fuel is ignited to produce a combustion reaction in one or more combustion chambers 136. The products of the combustion reaction drive the turbine 140.

[0033] The turbine 140 may include one or more turbine rotor components 142 and a stator assembly 144 (e.g., a nozzle). Each turbine rotor component 142 may correspond to one of a plurality of stages or a series of stages. The turbine 140 extracts energy from the fuel as the combusted fuel gas mixture passes through each stage. The energy extracted by the turbine 140 may be transferred via the power output coupling 104 (e.g., to an external system), and to the compressor 120 via the shaft 102.

[0034] The exhaust gas E from the turbine 140 may flow into the exhaust outlet 150. The exhaust outlet 150 may include an exhaust diffuser 152 that diffuses the exhaust gas E and an exhaust collector 154 that collects, redirects, and outputs the exhaust gas E. It should be understood that the exhaust gas E output by the exhaust collector 154 may be further processed, for example, to reduce harmful emissions, recover heat, etc. In addition, although the exhaust gas E is shown as flowing out of the exhaust outlet 150 in a particular direction and at an angle substantially perpendicular to the longitudinal axis L, it should be understood that the exhaust outlet 150 may be configured to output the exhaust gas E in any direction and at any angle suitable for a particular application of the gas turbine engine 100.

[0035] Figure 2 A block diagram of an exemplary closed system 200 including a gas turbine engine 100 is shown according to an embodiment. Although specific components are shown, one or more of the components shown may be omitted from closed system 200, and / or additional components may be incorporated into closed system 200. Additionally, although a specific arrangement of components is shown, the components may be arranged differently within closed system 200.

[0036] As shown, the closed system 200 may include an air inlet 210, a mixer box 300, a generator 220, a gas turbine engine 100, valves 230 and 235, a cooling system 240, an oxygen mixer 250, and a carbon capture system 260. During operation, the air inlet 210 may draw in and filter an external gas 205, such as fresh air, and introduce the filtered external gas 205 into the closed system 200 as an intake air 215. The intake air 215 and the recirculated exhaust gas 255 may flow into the mixer box 300, where they are mixed together to produce a mixed gas 305. The mixed gas 305 flows into the gas turbine engine 100 (e.g., into the inlet 110) as a working fluid F, which may provide power to the generator 220 (e.g., via the output coupling 104). As described above, the gas turbine engine outputs the exhaust gas E (e.g., via the exhaust outlet 150) as the exhaust gas 225.

[0037] The exhaust gas 225 may flow through an exhaust gas recirculation system including valve 230, a cooling system 240, and / or an oxygen mixer 250. During startup or during a non-recirculation cycle, valve 230 may be closed while valve 235 is open, allowing the exhaust gas 225 to be released into the atmosphere. To begin recirculating the exhaust gas 225, valve 230 is transitioned to fully open, while valve 235 is transitioned to fully closed, allowing the exhaust gas 225 to flow into the cooling system 240. Conversely, during shutdown, valve 235 may be transitioned to fully open, while valve 230 is transitioned to fully closed. The cooling system 240 may cool the exhaust gas 225 to produce cooled exhaust gas 245. The cooling system 240 may include a direct contact cooler (DCC). The cooled exhaust gas 245 may flow out of the cooling system 240 and be divided into at least two paths. For example, the cooled exhaust gas 245 may be split into a first path to the oxygen mixer 250 and a second path to the carbon capture system 260 according to a set or controlled ratio (e.g., 45% to the oxygen mixer 250, 55% to the carbon capture system 260). The oxygen mixer 250 may mix the cooled exhaust gas 245 with oxygen to produce a recirculated exhaust gas 255, which is mixed with the intake air 215 in the mixer box 300 to produce a mixed gas 305 as a working fluid F for the gas turbine engine 100, as described above. The carbon capture system 260 may capture and store, sequester, or use (e.g., for fracking) carbon dioxide within the cooled exhaust gas 245. It should be understood that such recirculation of the exhaust gas through the closed system 200 may be continuous throughout the operation of the gas turbine engine 100 within the closed system 200.

[0038] Figure 3 1 shows a perspective view of a mixer box 300 according to an embodiment. The mixer box 300 is shown and described herein with respect to a set of axes X, Y, and Z. Figure 2 In the illustrated closed system 200, the X-axis of the mixer box 300 is parallel to the longitudinal axis L of the gas turbine engine 100, and the upstream and downstream directions of the mixer box 300 are the same as those of the gas turbine engine 100. However, it should be understood that the X-axis of the mixer box 300 may be oriented in any manner relative to the longitudinal axis L of the gas turbine engine 100, and / or the upstream and downstream directions of the mixer box 300 may be different from those of the gas turbine engine 100, depending on specific design goals and constraints.

[0039] The mixer box 300 may include a first duct 310 and a second duct 320, the first duct forming a first flow path for the intake air 215 along the X axis, and the second duct forming a second flow path for the recirculated exhaust gas 255 along the Y axis. For example, the first duct 310 may include a cube having open sides on opposite ends along the X axis (i.e., in the YZ plane), representing the upstream and downstream ends of the first duct 310 relative to the first flow path of the intake air 215. Similarly, the second duct 320 may include a cube having open sides on opposite ends along the Y axis (i.e., in the XZ plane), representing the upstream and downstream ends of the second duct 320 relative to the second flow path of the recirculated exhaust gas 255. One of the open sides of the second duct 320 may face one or more openings in a side of the first duct 310 perpendicular to the Y axis (i.e., in the XZ plane), so that the second flow path for the recirculated exhaust gas 255 flows into the first flow path for the intake air 215. The first conduit 310 and the second conduit 320 can be formed as two separate conduits (e.g., made of the same material or different materials) that are permanently fixed to each other (e.g., via welding) or removably fixed to each other (e.g., via nuts and bolts, screws and / or other fastening devices) in the described configuration. Alternatively, the first conduit 310 and the second conduit 320 can be formed as a single integral conduit (e.g., made of the same material).

[0040] The first conduit 310 may house one or more mixers 400. In the illustrated embodiment, the first conduit 310 houses three mixers 400. However, the first conduit 310 may house any number of mixers 400, including one mixer 400, two mixers 400, four mixers 400, etc., depending on specific design goals and constraints. Each mixer 400 may be a cubic structure extending along the X-axis between the upstream and downstream ends of the two openings of the first conduit 310, and extending along the Y-axis from a first side of the first conduit 310 to which the second conduit 320 is fixed. Each mixer 400 may have a hollow interior having an open end at a first side of the first conduit 310, the open end being aligned with an opening through the first side of the first conduit 310, the opening being within a second flow path through the second conduit 320. The mixers 400 may be spaced apart (eg, equidistantly) along the Z axis such that a cuboid channel 315 is formed between adjacent mixers 400 and / or between the mixers 400 and a side of the first conduit 310 in the XY plane.

[0041] Each mixer 400 may include a front surface 410 facing the upstream direction of the first pipe 310, a rear surface 420 facing the downstream direction of the first pipe 310, and two side surfaces 430 extending between the front surface 410 and the rear surface 420. Each rear surface 420 may include at least one hole 422. Preferably, each rear surface 420 includes a plurality of holes 422, as shown by holes 422A, 422B to 422N, aligned in at least one dimension along the Y axis. Similarly, each side surface 430 may include at least one hole 432. Preferably, each side surface 430 includes a plurality of holes 432, as shown by holes 432A, 432B to 432N, aligned in two dimensions along the X axis and the Y axis. Although a specific arrangement of holes 422 and 432 is shown, it should be understood that other arrangements are also possible, such as, for example, a two-dimensional arrangement of holes 422 passing through the rear surface 420 along the Y axis and the Z axis. In any event, each aperture 422 and 432 forms a flow path between the hollow interior of the mixer 400 , placing the hollow interior of the mixer 400 in fluid communication with the exterior of the mixer 400 , including the passage 315 .

[0042] The second duct 320 may accommodate one or more flow guide covers 330. In the illustrated embodiment, the second duct 320 accommodates two flow guide covers 330. However, the second duct 320 may accommodate any number of flow guide covers 330, depending on specific design goals and constraints, including one flow guide cover 330, three flow guide covers 330, four flow guide covers 330, etc. Each flow guide cover 330 may include a generally U-shaped or V-shaped structure having a specific profile corresponding to the desired aerodynamics and having an apex facing the open end of the second duct 320, which is opposite to the end of the second duct 320 fixed to the first duct 310. Therefore, each flow guide cover 330 is used to divide the flow path of the gas entering the open end of the second duct 320 into two separate flow paths 325. In the illustrated embodiment, the two flow guide covers 330 divide the flow path into three separate flow paths 325.

[0043] Each flow path 325 may correspond to one mixer 400 in the first duct 310. In other words, for each flow path 325, the side of the first duct 310 to which the second duct 320 is fixed may include an opening aligned with the open end of one of the flow path 325 and the mixer 400. Therefore, the gas flowing along the flow path 325 flows through the aligned openings and enters the aligned mixer 400. Therefore, it should be understood that the number of mixers 400, the number of openings on the side of the first duct 310 to which the second duct 320 is fixed, and the number of channels 325 in the mixer box 300 may all be the same. In addition, the number may be one more than the number of shrouds 330 in the mixer box 300.

[0044] Figure 4 A cross-sectional perspective view of a mixer box 300 cut in an XZ plane according to an embodiment is shown. As shown, the front surface 410 of the mixer 400 can be generally U-shaped or V-shaped, with a profile corresponding to the desired aerodynamics, and with an apex facing the open upstream end of the first duct 310. Therefore, the front surface 410 is used to divide the flow path of the intake air 215 entering the upstream end of the first duct 310 into two separate channels 315, with a mixer 400 between each pair of adjacent channels 315. In other words, the intake air 215 is divided into separate channels 315 to flow between the mixers 400. In the illustrated embodiment, the three front surfaces 410 of the three mixers 400 divide the flow path into four separate channels 315.

[0045] Each mixer 400 may include one or more baffles 450 that divide the hollow interior of the mixer 400 into different channels or columns extending along the Y axis. In the illustrated embodiment, each mixer 400 includes four baffles 450, thereby dividing the hollow interior of the mixer 400 into four different channels. It is worth noting that the hollow area formed by the front surface 410 and the frontmost baffle 450 is not considered to be a channel because, in the illustrated embodiment, the hollow area is completely enclosed without an inlet or outlet. However, in an alternative embodiment, the hollow area may include an inlet and / or one or more outlets to form a channel that can function in the same or similar manner as other channels within the mixer 400.

[0046] Figure 5 A cross-sectional perspective view of a mixer box 300 cut in the YZ plane according to an embodiment is shown. Each air guide shroud 330 divides the flow path of the recirculated exhaust gas 255 into two separate flow paths 325. Each flow path 325 is aligned with an opening 312 in one side of the first duct 310 to which the second duct 320 is fixed. In addition, each mixer 400 is aligned with one of these openings 312. Therefore, the recirculated exhaust gas 255 is divided into separate flow paths 325 to flow into the hollow interior of the mixer 400 through the opening 312 in the first duct 310. In an embodiment in which each mixer 400 includes a baffle 450, the recirculated exhaust gas 255 is further divided into separate channels formed by the baffle 450 within the hollow interior of the mixer 400. It is noteworthy that the use of baffles 450 to separate the hollow interior of the mixer 400 helps prevent the formation of vortices within the mixer 400. The vortex may cause a low pressure area within the hollow interior of the mixer 400, which may cause gas from outside the mixer 400 to flow into the hollow interior of the mixer 400 via holes 422 and / or 432, referred to as "ingress."

[0047] As shown, each mixer 400 may be open on an end adjacent to the side of the first duct 310 including the opening 312, so that the recirculated exhaust gas 255 may flow into the hollow interior of each mixer 400 through the open end of the mixer 400. In addition, each mixer 400 may include a base plate 440 on an end of the mixer 400, which is opposite the open end of the mixer 400 along the Y axis. In alternative embodiments, the base plate 440 may be omitted because the end of the mixer 400 that would otherwise have the base plate 440 may alternatively be closed by the side of the first duct 310. However, the use of the base plate 440 may facilitate the fastening of the mixer 400 to the first duct 310, for example, via welding.

[0048] Figure 6 A perspective view of a single mixer 400 according to an embodiment is shown. As shown, the hole 422 in the rear surface 420 can have a larger area (e.g., diameter) closer to the open end of the mixer 400 and a smaller area (e.g., diameter) closer to the closed end of the mixer 400, with a substrate 440. In particular, the area of ​​the hole 422 can gradually decrease from the open end to the closed end. For example, hole 422A has the largest area, hole 422N has the smallest area, and the hole 422 between hole 422A and hole 422N, such as hole 422B, has an area smaller than hole 422A, but an area larger than hole 422N. Although the hole 422 is described as gradually decreasing in area, two or more holes 422 from the open end to the closed end can have the same area, and / or the area of ​​the hole 422 can decrease from the open end to the closed end at an uneven or non-gradient rate. By biasing the area of ​​the holes 422 toward the holes 422 near the open end of the mixer 400, the reduction in the area of ​​the holes 422 from the open end to the closed end of the mixer 400 promotes more uniform mixing. This compensates for the cross-flow phenomenon that reduces the flow of the recirculated exhaust gas 255 through the holes 422 at the open end of the mixer 400 relative to the holes 422 at the closed end of the mixer 400.

[0049] Similarly and for the same reasons, the holes 432 in each side surface 430 can have a larger area (e.g., diameter) closer to the open end of the mixer 400 and a smaller area (e.g., diameter) closer to the closed end of the mixer 400, with the base plate 440. In particular, the area of ​​the holes 432 can gradually decrease from the open end to the closed end. For example, hole 432A has the largest area, hole 432N has the smallest area, and holes 432 between holes 432A and holes 432N, such as hole 432B, have a smaller area than hole 432A, but a larger area than hole 432N. Although the holes 432 are described as gradually decreasing in area, two or more holes 432 from the open end to the closed end can have the same area, and / or the area of ​​the holes 432 can decrease from the open end to the closed end at a non-uniform or non-gradient rate.

[0050] As shown, the holes 432 can be formed in a two-dimensional manner through each side surface 430. In this case, each column of holes 432 extending from the open end of the mixer 400 to the closed end can have the same configuration as the holes 432. Therefore, each hole 432 in each row of holes 432 extending from the front surface 410 to the rear surface 420 can have the same area. Although four columns of holes 432 and six rows of holes 432 are shown, it should be understood that the side surface 430 can include any number of columns and rows of holes 432 depending on specific design goals and limitations. In addition, although the rear surface 420 is shown as having only a single column of holes 422, the rear surface 420 can be configured to have multiple columns of holes 422 in a manner similar or the same as the side surface 430.

[0051] In the illustrated embodiment, each column of holes 432 in each side surface 430 is identical in the number, arrangement, and area of ​​holes 432. Additionally, the column of holes 422 is identical to each column of holes 432 in the number, arrangement, and area of ​​holes 422. In an alternative embodiment, each column of holes 432 in each side surface 430 may have a different number, arrangement, and / or area of ​​holes 432 than one or more other columns of holes 432 in the same side surface 430 and / or a different side surface 430. Additionally or alternatively, each column of holes 422 in each rear surface 420 may have a different number, arrangement, and / or area than one or more columns of holes 422 in the same rear surface 420 and / or a different rear surface 420 and / or one or more columns of holes 432 in one or more side surfaces 430.

[0052] A plurality of solder holes 434 may be formed between each pair of adjacent columns of holes 432 passing through each side surface 430. In the illustrated embodiment, a set of two staggered rows of solder holes 434 are formed between each adjacent column of holes 432. However, in alternative embodiments, fewer or more rows of solder holes 434 may be formed and / or differently arranged solder holes 434 may be formed between adjacent columns of holes 432. The solder holes 434 are aligned with the sides of the baffle 450 within the hollow interior of the mixer 400 so that the baffle 450 may be welded to the side 430 through the solder holes 434.

[0053] In addition, each side surface 430 may include one or more drain holes 436 adjacent to the edge of the substrate 440 along the side surface 430. Each drain hole 436 may be aligned with a channel (e.g., the center of a channel) formed within the hollow interior of the mixer 400 by the baffle 450. Thus, in the illustrated embodiment, since each column corresponds to one of the channels in the hollow interior of the mixer 400, a drain hole 436 is formed at the bottom of each column of holes 432. Since the gas within the mixer box 300 may be very humid, condensation may form within the hollow interior of the mixer 400. Each drain hole 436 enables condensation formed within the corresponding channel to flow out of the hollow interior of the mixer 400 into the channel 315, so that the condensation is not collected within the mixer 400. Instead, the condensation leaves the mixer 400 via the drain holes 436 and is reintroduced into the gas mixed within the channel 315. In embodiments, the surface of the base plate 440 within the hollow interior of the mixer 400 may be shaped, creased, grooved, or otherwise configured to direct condensate to the drain holes 436. Alternatively, the mixer 400 may rely solely on the pressure differential between the interior and exterior of the mixer 400 to force condensate out of the drain holes 436.

[0054] Figure 7 A perspective view of an isolated front surface 410 according to an embodiment is shown. As shown, the front surface 410 may have a generally U-shaped or V-shaped profile. The front surface 410 may be formed of a single material bent into a desired curvature. The long sides of the front surface 410 may be welded or otherwise fixed to the corresponding side surface 430.

[0055] Figure 8A perspective view of an independent rear surface 420 according to an embodiment is shown. As shown, the rear surface 420 may include a substrate 424 including holes 422 (e.g., 422A, 422B, ..., 422N) with two side portions 426A and 426B on each long side of the substrate 424. The substrate 424 and the side portions 426A and 426B may be integrally formed from a single piece of material, or may be formed as separate pieces of material connected together in any suitable manner. The rear surface 420 may be welded or otherwise fixed to the corresponding side surface 430 at the side portions 426A and 426B.

[0056] Fig. 9 A front view of an isolated side surface 430 according to an embodiment is shown. It should be understood that each mixer 400 may include two identical side surfaces 430. As described elsewhere herein, each side surface 430 may include multiple columns of holes 432 (e.g., 432A, 432B, ..., 432N). Each column of holes 432 that will be aligned with the channels in the hollow interior of the mixer 400 may also include a discharge hole 436 formed as a notch in the edge of the side surface 430 that will be fixed to the base plate 440. In addition, at least one row of plug welding holes 434 may be formed between adjacent columns of holes 432 so as to align with corresponding baffles 450 in the hollow interior of the mixer 400. In the illustrated embodiment, two staggered rows of plug welding holes 434 are provided for each baffle 450. It should be understood that the baffle 450 can be welded to the side surface 430 by aligning the baffle 450 with a set of plug welding holes 434 and welding through the plug welding holes 434.

[0057] Fig.10 A perspective view of an isolated substrate 440 according to an embodiment is shown. As shown, the substrate 440 may include a generally rectangular portion 444 having a profile corresponding to the profile of a component including the rear surface 420 and the two side surfaces 440, and a generally U-shaped or V-shaped portion 446 having a profile corresponding to the profile of the front surface 410. In other words, the substrate 440 has a profile that matches the profile of the mixer 400 in the XZ plane, thereby completely enclosing one end of the mixer 400 along the Y axis.

[0058] Fig.11A perspective view of an isolated baffle 450 is shown according to an embodiment. As shown, the baffle 450 can include a substrate 454 having two side portions 456A and 456B on each long side of the substrate 454. The substrate 454 and the side portions 456A and 456B can be integrally formed from a single piece of material, or can be formed as separate pieces of material connected together in any suitable manner. The baffle 450 can be welded or otherwise secured between a pair of side surfaces 430 at the side portions 456A and 456B (e.g., by welding through corresponding socket holes 434 through the side surfaces 430). It should be understood that each baffle 450 can be identical.

[0059] Fig.12 A perspective view of an isolated first conduit 310 according to an embodiment is shown. As shown, flanges 316 (e.g., 316A and 316B) are formed around the two open ends of the first conduit 310 to facilitate the engagement of the first conduit 310 within the conduit system of the closed system 200. In particular, the front flange 316A can be fixed (e.g., permanently via welding, or removably via nuts and bolts, screws, etc.) to a corresponding flange on a conduit supplying the intake air 215, and the rear flange 316B can be fixed (e.g., permanently via welding, or removably via nuts and bolts, screws, etc.) to a corresponding flange on a conduit supplying the mixed gas 305 as a working fluid F to the gas turbine engine 100. The two open ends of the first conduit 310 form a primary flow path through the first conduit 310, while a secondary flow path into the first conduit 310 is formed by an opening 312 on one side in a plane parallel to the primary flow path. In the illustrated embodiment, the primary flow path and the secondary flow path intersect at a perpendicular (i.e., 90 degree) angle. However, it should be understood that in alternative embodiments, the primary flow path and the secondary flow path can be configured to intersect at a non-perpendicular angle, such as by adjusting the shape of the first conduit 310, adjusting the shape of the second conduit 320, adding additional components, etc.

[0060] The first pipe 310 may also include a plurality of rows of socket holes 314 on a side opposite to the opening 312. In the illustrated embodiment, three rows of socket holes 314 are formed in each of the three groups, each group corresponding to one mixer 400. It should be understood that the number of groups of socket holes 314 will be equal to the number of mixers 400 accommodated in the first pipe 310 (e.g., three in the illustrated example), and the number of socket holes 314 in each row and / or the number of rows of socket holes 314 can be set to any suitable number. In any case, each mixer 400 can be aligned with a corresponding set of socket holes 314 and then welded to the first pipe 310 from the outside of the first pipe 310 through the socket holes 314.

[0061] Fig.13A perspective view of isolated shrouds 330 according to an embodiment is shown. Each shroud 330 can be formed as a generally U-shaped or V-shaped structure 334 with flat portions 336A and 336B on either side. The curved structure 334 and flat portions 326A and 326B can be integrally formed from a single piece of material, or can be formed as separate pieces of material connected together in any suitable manner. The shroud 330 can be welded to the second conduit 320 at the edge of the curved structure 334 and / or welded to the edge of the opening 312 of the first conduit 310 at the flat portions 336A and 336B.

[0062] Fig.14 The profile of the mixer box 300 in the YZ plane (i.e., looking down the X axis) according to an embodiment is shown. In an embodiment, in this profile, the total area of ​​the passages 315 is greater than the total area of ​​the mixer 400. For example, the total area of ​​the passages 315 can be 57% or more of the total cross-sectional area through the mixer box 300. In addition, each of the inner passages 315, illustrated as inner passages 315B and 315C, can have twice the cross-sectional area of ​​each of the outer passages 315A and 315D because the inner passages 315B and 315C receive twice the amount of recirculated exhaust gas 255 (i.e., from both side surfaces 430 of the adjacent mixer 400).

[0063] Fig.15A perspective cross-sectional view of a portion of the closed system 200 with the mixer box 300 installed according to an embodiment is shown. During operation, the intake air 215 output by the air inlet 210 flows into the first duct 310 of the mixer box 300 along the X-axis. It should be understood that the flow path of the intake air 215 is divided into channels 315 by the front surface 410 of each mixer 400, so that the intake air 215 flows between the mixers 400. At the same time, the recirculated exhaust gas 255 output by the exhaust gas recirculation system (e.g., output by the oxygen mixer 250) flows into the second duct 320 of the mixer box 300 along the Y-axis. It should be understood that the flow path of the recirculated exhaust gas 255 is divided into channels 335 by the guide cover 330, so that the recirculated exhaust gas 255 flows through the opening 312 in the first duct 310 and flows into the hollow interior of the mixer 400. Within the hollow interior of the mixer 400, the recirculated exhaust gas 255 can be further divided into channels formed by the baffle 450 within each mixer 400. As the recirculated exhaust gas 255 flows through the hollow interior of the mixer 400, the recirculated exhaust gas 255 flows out of each mixer 400 through the column of holes 422 in the rear surface 420 and the column of holes 432 in the side surface 430. The holes 422 and 432 may have a larger area at the open end of each mixer 400 than at the closed end of each mixer 400 to produce a more uniform diffusion of the recirculated exhaust gas 255 into the intake air 215 flowing through the passage 315. The recirculated exhaust gas 255 exiting the holes 422 and 432 mixes with the intake air 215 flowing through the passage 315 to produce a mixed gas 305 as a working fluid F input to the gas turbine engine 100.

[0064] As shown, the recirculated exhaust gas 255 (e.g., output by the oxygen mixer 250) can flow through a first length of the duct 1510 before entering the mixer box 300. The first length of the duct 1510 can be configured to ensure that the oxygen added by the oxygen mixer 260 is fully mixed into the recirculated exhaust gas 255 before entering the mixer box 300. In an embodiment, the first length of the duct 1510 can be a diffuser that widens from the upstream end toward the downstream connection to the mixer box 300 to slow the flow of the recirculated exhaust gas 255 and match the size of the open end of the second duct 320 to maximize the mixing potential within the mixer box 300. Similarly, the mixed gas 305 can flow through a second length of the duct 1520 after leaving the mixer box 300. The second length of the duct 1520 can be configured to ensure that the intake air 215 and the recirculated exhaust gas 255 are fully mixed before entering the compressor 120 of the gas turbine engine 100.

[0065] Although the primary flow path through the first conduit 310 is described herein as a flow path for the intake air 215, and the secondary flow path through the second conduit 320 is described herein as a flow path for the recirculated exhaust gas 255, in alternative embodiments, these flow paths may be switched. In this case, the recirculated exhaust gas 255 may flow into the open upstream end of the first conduit 310, while the intake air 215 may flow through the second conduit 320, through the opening 312, into the mixer 400 outflow holes 422 and 432. It should be understood that other components of the closed system 200 may be adapted to address this different configuration of flow paths.

[0066] Each component of the mixer box 300 can be made of any suitable material. In an embodiment, the components are made of stainless steel, such as 304 grade stainless steel. However, it should be understood that the components can be made of other materials, such as carbon steel. In addition, all components of the mixer box 300 can be made of the same material, or one or more components of the mixer box 300 can be made of a different material than one or more other components of the mixer box 300.

[0067] Industrial Applicability

[0068] In a closed system 200 that recirculates the exhaust gas 225 from the gas turbine engine 100, the recirculated exhaust gas 255 should be mixed with the intake air 215 in a manner that does not produce an excessive pressure drop, because an excessive pressure drop may be detrimental to the performance of the gas turbine engine 100. The performance of the gas turbine engine 100 may also be impaired if the gas distribution within the resulting mixed gas 305 entering the gas turbine engine 100 is not relatively uniform. This may be particularly problematic when site constraints and / or other design constraints limit the length of ducting for the intake air 215 and the recirculated exhaust gas 255 to mix.

[0069] Thus, a mixer box 300 is disclosed for efficient mixing of intake air 215 and recirculated exhaust gas 255 to produce a mixed gas 305 with an acceptably uniform distribution in a short duct length without excessive pressure drop. The mixer box 300 is compact so that an existing closed system 200 can be easily retrofitted with the mixer box at an existing mixing point. Alternatively, the closed system 200 can be first constructed with the mixer box 300.

[0070] The mixer box 300 produces a more uniform distribution in the mixed gas 305 through the mixer 400. In particular, each mixer 400 extends the entire length of the Y axis between the first side and the second side of the first pipe 310. Therefore, when the recirculated exhaust gas 255 flows through the opening 315 in the first side of the first pipe 310, the recirculated exhaust gas 255 does not simply enter the main flow path through the first pipe 310. On the contrary, because the recirculated exhaust gas 255 is guided into the hollow interior of the mixer 400, the flow of the recirculated exhaust gas 255 is forced to extend between the first side and the second side of the first pipe 310 along the entire length of the Y axis. In other words, the secondary flow path of the recirculated exhaust gas 255 is forced to be perpendicular to the main flow path along the entire height of the main flow path on the Y axis. In addition, the mixer 400 can extend along the X axis from the open upstream end to the entire length of the first pipe 310 at the open downstream end. Therefore, the secondary flow path of the recirculated exhaust gas 255 is also forced to extend the entire length of the first pipe 310. This extension of the secondary flow path through the primary flow path along the X-axis and the Y-axis promotes more uniform mixing by providing more uniform injection of the recirculated exhaust gas 255 into the flow path of the intake air 215 .

[0071] Additionally, the area of ​​the holes 422 and 432 that provide a flow path from the hollow interior to the exterior of each mixer 400 may be increased from the closed end to the open end of each mixer 400. This increases the volume of the recirculated exhaust gas 255 injected from the holes 422 / 432 that are closer to the open end of the mixer 400 relative to the holes 422 / 432 that are closer to the closed end of the mixer 400 in order to compensate for the natural deviation of the recirculated exhaust gas 255 to remain in the secondary flow path until reaching the closed end of the mixer 400. As a result, the volume of the recirculated exhaust gas 255 injected from the holes 422 / 432 is more uniform throughout the length of the mixer 400 along the Y axis to again promote more uniform mixing by providing a more uniform injection of the recirculated exhaust gas 255 into the flow path of the intake air 215.

[0072] In addition, each mixer 400 may include baffles 450 that divide the hollow interior into channels. Dividing the hollow interior of each mixer 400 into these channels helps prevent vortices from forming within the hollow interior of the mixer 400. Such vortices can create low pressure areas within the mixer 400, which can cause gas to enter the mixer 400. Thus, the baffles 450 also promote more uniform mixing by promoting higher pressures within the hollow interior of the mixer 400.

[0073] Unless expressly excluded, the use of the singular to describe a component, structure, or operation does not exclude the use of a plurality of such components, structures, or operations or their equivalents. "One," "an," "the," "at least one," "one or more," and similar terms used in the present invention (particularly in the context of the appended claims) should be interpreted as covering the singular and the plural, unless otherwise specified herein or clearly contradictory to the context. Unless otherwise specified herein or clearly contradictory to the context, the use of the term "at least one" or "one or more" followed by a list of one or more items (e.g., "at least one of A and B" or "one or more of A and B") should be understood to refer to an item selected from the listed items (e.g., only A or only B) or any combination of two or more listed items (e.g., A and B; A, B and B; A and A; B and B; etc.). Similarly, the word "or" used herein refers to any possible arrangement of a group of items. For example, the phrase "A, B or C" means at least one of A, B or C or any combination thereof, such as A; B; C; A and B; A and C; B and C; A, B and C; or a plurality of any items, such as A and A; B, B and C; A, A, B, C and C; and so on.

[0074] It should be understood that the above benefits and advantages may relate to one embodiment or may relate to several embodiments. Aspects described in conjunction with one embodiment are intended to be usable with other embodiments. Any description associated with one embodiment applies to similar features of other embodiments, and elements of multiple embodiments may be combined to form other embodiments. The embodiments are not limited to those embodiments that solve any or all of the problems, or those embodiments that have any or all of the benefits and advantages.

[0075] The foregoing detailed description is merely exemplary in nature and is not intended to limit the invention or the application and use of the invention. The described embodiments are not limited to use in conjunction with a particular type of machine. Therefore, although for ease of explanation, embodiments of the present invention are depicted and described as being implemented in a closed system with a gas turbine engine, it should be understood that the present invention can be implemented in various other types of systems in which gases are mixed and can be implemented in conjunction with various other types of machines in various other environments. In addition, it is not intended to be bound by any theory presented in any of the preceding sections. It should also be understood that, unless restrictive, these illustrations may include exaggerated dimensions and graphic representations to better illustrate the referenced items shown and are not to be considered restrictive.

Claims

1. A mixer box (300), comprising: A first pipeline (310), the first pipeline comprising an upstream end and a downstream end along a first axis (X), both of which are open to form a first flow path along the first axis (X) through the first conduit (310), a first side and a second side along a second axis (Y) perpendicular to the first axis (X), the first side comprising one or more openings (312), and one or more mixers (400), each of the mixers extending along the first axis (X) between the upstream end and the downstream end and along the second axis (Y) between the first side and the second side so that the first flow path is divided into a plurality of channels (315), wherein each of the one or more mixers (400) has an open end at the first side, the open end being aligned with one of the one or more openings (312) in the first side so that a second flow path perpendicular to the first flow path is formed through the first side into the hollow interior of the mixer (400), Each of the one or more mixers (400) includes two side surfaces (430), each of the two side surfaces includes a plurality of holes (432), each of the holes forming a flow path between the hollow interior of the mixer (400) and one of the plurality of channels (315).

2. The mixer box (300) of claim 1, wherein an area of ​​the plurality of holes (432) in each of the two side surfaces (430) of each of the one or more mixers (400) decreases as the distance from the open end of the mixer (400) increases.

3. The mixer box (300) of claim 1, wherein the plurality of holes (432) are arranged in a two-dimensional manner along the first axis and the second axis in each of the two side surfaces (430) of each mixer of the one or more mixers (400).

4. The mixer box (300) of claim 1, wherein each of the one or more mixers (400) includes a rear surface (420), and wherein the rear surface (420) includes a plurality of holes (422), each of the plurality of holes forming a flow path between the hollow interior of the mixer (400) and the exterior of the mixer (400).

5. The mixer box (300) of claim 4, wherein the area of ​​the plurality of holes (422) in each rear surface (420) of each of the one or more mixers (400) decreases with increasing distance from an open end of the mixer (400).

6. The mixer box (300) of claim 1, wherein the one or more mixers (400) is a plurality of mixers (400).

7. The mixer box (300) of claim 6, wherein the plurality of mixers (400) comprises at least three mixers (400).

8. The mixer box (300) of claim 1, wherein each of the one or more mixers (400) comprises a curved front surface (410).

9. The mixer box (300) of claim 1, wherein each of the one or more mixers (400) comprises one or more baffles (450), each of the baffles extending along the second axis such that the hollow interior of the mixer (400) is divided into a plurality of channels along the second axis.

10. The mixer box (300) of claim 9, wherein each of the plurality of channels in the hollow interior of each of the one or more mixers (400) is aligned with a column of the plurality of holes (422) in each of the two side surfaces (430) of the mixer (400).

11. The mixer box (300) of claim 10, wherein at least one of the two side surfaces (430) of each of the one or more mixers (400) includes a discharge hole (436) through an edge of the side surface (430) opposite the open end of the mixer (400) along the second axis.

12. The mixer box (300) according to claim 1, further comprising a second conduit (320), the second conduit comprising a first end and a second end along the second axis (Y), wherein the second conduit (320) is fixed to the first side of the first conduit (310) at the first end, and the first end and the second end are both open so that the second flow path of each mixer of the one or more mixers (400) extends through the second conduit (320).

13. The mixer box (300) of claim 12, wherein the second conduit (320) receives one or more flow guide shields (330) that divide the second flow path through the second conduit (320) into a plurality of channels (325).

14. The mixer box (300) of claim 13, wherein each of the plurality of channels (325) of the second flow path through the second conduit (320) is aligned with one of the one or more openings (312) in the first side of the first conduit (310), such that each of the plurality of channels (325) of the second flow path through the second conduit (320) is fluidly connected to the open end of one of the one or more mixers (400) through the aligned openings (312).

15. A system, comprising: Air inlet (210); A gas turbine engine (100); Exhaust gas recirculation system (230, 240, 250); as well as A mixer box (300) according to any one of the preceding claims, wherein the mixer box (300) is configured such that the first flow path is in fluid communication with an output of the air inlet (210) on an upstream end of the first duct (310) and an inlet (110) of the gas turbine engine (100) on a downstream end of the first duct (310), and each second flow path is in fluid communication with an output of the exhaust gas recirculation system (230, 240, 250).

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