Compressor bleed air expansion system

Abstract

System that has: a bleed air system (36) configured to direct a bleed air flow (42) from a high pressure region (44) to a low pressure region (46), the bleed air system (36) comprising: a valve (38); and a stepped bleed air line (40) configured to progressively lower the pressure of the bleed air flow (42), the stepped bleed air line (40) comprising: an inlet (50) coupled to the valve (38); a first stage (58) coupled to the inlet (50), the first stage (58) configured to reduce the pressure of the bleed air flow (42); a second stage (60) coupled to the first stage (58), the second stage (60) being configured to reduce the pressure of the bleed air flow (42); and an outlet (52) coupled to the second stage (60), the inlet (50) and the outlet (52) being arranged along parallel axes, a first expansion section (84) coupled between the inlet (50) and the first stage (58), the first expansion section (84) having a first percentage of expansion, a second expansion section (88) coupled between the first stage (58) and the second stage (60), the second expansion section (88) having a second percentage of expansion, each step having a constant dimension along its longitudinal extent, wherein the stepped bleed air line (40) has at least one diffuser plate (80) configured to reduce the pressure of the bleed air flow (42), and wherein the at least one diffuser plate (80) is arranged at the inlet (50), the first stage (58), the second stage (60), or the outlet (52), or a combination thereof.

Description

BACKGROUND TO THE INVENTION

[0001] The subject matter disclosed herein relates to gas turbines, for example, a system and method for expanding compressor bleed air.

[0002] Gas turbine systems generally include a compressor, a combustor, and a turbine. The combustor burns a mixture of compressed air and fuel to produce hot combustion gases, which are directed to the turbine to perform work, such as driving an electric generator. The compressor compresses air from an air intake and then directs the compressed air to the combustor. However, some of the compressed air cannot be directed to the combustor at all times. Some of the compressed air may be directed from the compressor to other parts of the gas turbine system. Directing the compressed air to a lower pressure can cause vibration and noise within the gas turbine system.

[0003] US 2010 / 0 043 447 A1 describes, among other things, a bypass duct in a gas turbine with a bleed valve arrangement comprising a cascade of elements that generate pressure differences to achieve noise reduction. These elements are curved, perforated plates.

[0004] US 2010 / 0 115 964 A1 describes a device for noise reduction in a gas turbine bleeder. The device includes partitions with openings that cause contractions and sudden expansions of the flow through the device. Turbulators are provided between the partitions to break up jets emerging from the openings. Breaking up the jets before they impact the partitions is intended to allow the partitions to be arranged closer together, thus achieving noise reduction in a device with a relatively small thickness.

[0005] US 2009 / 0 320 496 A1 describes, among other things, a diffuser device designed to diffuse a bleed air flow. The bleed air, which passes through a valve for regulating the bleed air flow, flows through a pipe before entering the diffuser device. The diffuser device is located at the outlet of the pipe.

[0006] Based on this, it is the object of the invention to provide a bleed air system with a stepped bleed air line which enables a reduction of vibrations and / or noise of the bleed air system, including the valve and / or the exhaust outlet downstream of the bleed air system. BRIEF DESCRIPTION OF THE INVENTION

[0007] The problem is solved by the system according to claims 1, 8 and 9.

[0008] Certain embodiments consistent with the originally claimed invention are summarized below. These embodiments are not intended to limit the scope of the claimed invention; rather, these embodiments are intended merely to provide a brief summary of the possible forms of the invention. Indeed, the invention may take many forms that may be similar to or different from the embodiments set forth below.

[0009] In a first embodiment, a system includes a bleed air system configured to direct a bleed air flow from a high-pressure region to a low-pressure region. The bleed air system includes a valve and a staged bleed air line configured to progressively lower the pressure of the bleed air flow. The staged bleed air line includes an inlet coupled to the valve, a first stage configured to lower the pressure of the bleed air flow and coupled to the inlet, a second stage configured to lower the pressure of the bleed air flow and coupled to the first stage, and an outlet coupled to the second stage. The inlet and the outlet are arranged along parallel axes.

[0010] At least one of the first stage and / or the second stage of the system is / are configured to lower the pressure of the bleed air flow by expansion, wherein the inlet, the outlet, the first stage and the second stage are arranged along parallel axes.

[0011] The staged bleed air line of any of the above-mentioned systems includes at least one diffuser plate configured to reduce the pressure of the bleed air flow, the at least one diffuser plate being disposed at the inlet, the first stage, the second stage, or the outlet, or a combination thereof.

[0012] Either the first stage and / or the second stage of the above-mentioned system may be configured to lower the pressure of the bleed air flow by expansion.

[0013] A first diffuser plate of the at least one diffuser plate of any of the above-mentioned systems may be disposed in the stepped bleed air line at a first location having a first cross-sectional area, and the first diffuser plate may have a plurality of apertures having a total aperture area, wherein the total aperture area is greater than 40% of the cross-sectional area.

[0014] Each diffuser plate of the at least one diffuser plate of any of the above-mentioned systems may have a plurality of apertures, and each of the plurality of apertures has a common dimension.

[0015] Each diffuser plate of the at least one diffuser plate of any of the above-mentioned systems may have a plurality of apertures, and a size of the plurality of apertures may be based at least in part on a dimension of the stepped bleed air line at a location on the respective diffuser plate.

[0016] The parallel axes of any of the above-mentioned systems may consist of a common axis.

[0017] The bleed air system of any of the above-mentioned systems may be configured to reduce vibrations within the valve or the staged bleed air line.

[0018] Any system mentioned above may include a high pressure section, wherein the high pressure section may include a compressor, and a gas turbine coupled to the compressor.

[0019] The compressor of any of the above-mentioned systems may be configured to produce a compressed air flow and the bleed air flow, and the valve may be configured to regulate the bleed air flow to less than about 10% of the compressed air flow.

[0020] In a second embodiment, a system includes a bleed air system configured to direct a bleed air flow from a high-pressure region to a low-pressure region. The bleed air system includes a staged bleed air line configured to progressively lower the pressure of the bleed air flow. The staged bleed air line has a variable line dimension. The staged bleed air line includes an inlet configured to be coupled to the high-pressure region, a first stage coupled to the inlet and configured to lower the pressure of the bleed air flow through expansion, a second stage coupled to the first stage and configured to lower the pressure of the bleed air flow through expansion, and an outlet coupled to the second stage.The inlet has an inlet dimension, the first stage has a first dimension greater than the inlet dimension, and the second stage has a second dimension greater than the first dimension. The inlet, first stage, second stage, and outlet are arranged along parallel axes.

[0021] The staged bleed air line of the system comprises: a first expansion section coupled between the inlet and the first stage, the first expansion section having a first percentage of expansion; a second expansion section coupled between the first stage and the second stage, the second expansion section having a second percentage of expansion.

[0022] The first percentage of expansion and the second percentage of expansion can range from approximately 10 to 40%.

[0023] The first stage of any of the above-mentioned systems may have a first length that is between about 3.5 and 4.5 times greater than the first dimension, and the second stage may have a second length that is between about 3.5 and 4.5 times greater than the second dimension.

[0024] The stepped bleed air line of any of the aforementioned systems may include: a first diffuser plate coupled between the inlet and the first stage, wherein the first diffuser plate may include a plurality of first apertures, each aperture of the plurality of first apertures having a first aperture dimension between about 20% and about 30% of the inlet dimension; and a second diffuser plate coupled between the first stage and the second stage, wherein the second diffuser plate may include a plurality of second apertures, each aperture of the plurality of second apertures having a second aperture diameter between about 20% and about 30% of the first dimension.

[0025] The system may comprise: the high-pressure region, wherein the high-pressure region may comprise a compressor; and a gas turbine coupled to the compressor.

[0026] In a third embodiment, a system includes a gas turbine having a compressor configured to generate a bleed air flow, a gas turbine coupled to the compressor, an exhaust outlet configured to receive an exhaust flow and the bleed air flow, and a bleed air system configured to direct the bleed air flow from the compressor to the exhaust outlet. The bleed air system includes a staged bleed air line configured to progressively lower the pressure of the bleed air flow.The staged bleed air line includes an inlet coupled to the compressor, a first stage coupled to the inlet, the first stage configured to lower the pressure of the bleed air flow through expansion, a second stage coupled to the first stage, the second stage configured to lower the pressure of the bleed air flow through expansion, an outlet coupled to the second stage, and at least one diffuser plate configured to lower the pressure of the bleed air flow. The inlet has an inlet diameter, the first stage has a first diameter greater than the inlet diameter, and the second stage has a second diameter greater than the first diameter. The outlet is configured to direct the bleed air flow to the exhaust outlet.The inlet, first stage, second stage and outlet are arranged along parallel axes.

[0027] The compressor of the system may be configured to produce a compressed air flow, and the bleed air system may include a valve configured to regulate the bleed air flow to less than approximately 10% of the compressed air flow.

[0028] The at least one diffuser plate of any of the above-mentioned systems may include a first diffuser plate coupled to the first stage, a second diffuser plate coupled to the second stage, and a third diffuser plate coupled to the outlet. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] These and other features, aspects and advantages of the present invention will be better understood when the following detailed description is read with reference to the accompanying drawings, in which like reference characters represent like parts throughout the drawings, in which: Fig. 1 is a schematic block diagram of an embodiment of a gas turbine system with a bleed air system; Fig. 2 a perspective view of an embodiment of the bleed air system of the gas turbine system according to Fig. 1; Fig. 3 a perspective view of an embodiment of the bleed air system of the gas turbine system according to Fig. 1; and Fig. 4 a front view of an embodiment of a diffuser plate of the bleed air system according to Fig. 2. DETAILED DESCRIPTION OF THE INVENTION

[0030] When introducing elements of various embodiments of the present invention, the articles "a," "an," "the," and "the" are intended to mean that one or more of the elements may be present. The terms "comprising," "including," and "having" are intended to be inclusive and to mean that additional elements may be present in addition to those listed.

[0031] A variety of systems, such as compressors, pumps, turbines, and various turbomachinery, may use a bleed air system to transfer fluid from one location to another. The bleed air system may receive bleed air flow from a high-pressure region and direct the bleed air flow to a low-pressure region. A staged bleed air line of the bleed air system is configured to gradually reduce the pressure of the bleed air flow to reduce vibration and / or noise of the bleed air system, such as vibration of a bleed air valve. The staged bleed air line may have at least two stages to successively (e.g., stepwise) reduce the pressure of the bleed air flow. Each stage of the staged bleed air flow includes an expansion section and / or a diffuser plate.The number of stages may be determined at least in part based on the pressure difference between the high-pressure region and the low-pressure region. Multiple stages may be used for larger pressure differences than for small pressure differences. Each stage may have a constant dimension (e.g., a constant diameter) along its length or may widen downstream. The expansion sections increase the dimension of the stepped bleed air line to at least reduce the static pressure of the bleed air flow. The diffuser plates partially impede the bleed air flow and allow the bleed air flow to pass through orifices. The diffuser plates are configured to at least reduce the kinetic energy or dynamic pressure of the bleed air flow. The characteristics of the expansion sections (e.g., percentage of expansion, size, cross-sectional shape, length) and the diffuser plates (e.g.,Various factors (e.g., aperture size, aperture number, aperture shape, aperture configuration, diffuser plate size) influence the vibration of the bleed air system. Various combinations of expansion sections and / or diffuser plates may be used together within the stepped bleed air line. The stepped bleed air line is configured with the stages comprising an expansion section and / or diffuser plates arranged along the stepped bleed air line to reduce the vibration of the bleed air system. In some embodiments, the stepped bleed air line may also reduce vibrations downstream of the aperture system.

[0032] By referring to the drawings and first to Fig. 1, a block diagram of one embodiment of a gas turbine system 10 is illustrated. As described in detail below, the disclosed gas turbine system 10 (e.g., a gas turbine engine) may utilize one or more fuel nozzles 12 to mix a fuel 14 with compressed air 16. The gas turbine system 10 may utilize liquid or gaseous fuel 14, such as natural gas and / or a hydrogen-rich syngas, to operate the gas turbine system 10. As illustrated, the one or more fuel nozzles 12 receive the fuel 14, mix the fuel 14 with the compressed air 16, and distribute the air-fuel mixture into a combustor 18 in a ratio suitable for optimal combustion, emissions, fuel consumption, and power output.The air-fuel mixture burns within the combustion chamber 18, producing hot, pressurized exhaust gases 20. The combustion chamber 18 directs the exhaust gases 20 through a gas turbine 22 toward an exhaust outlet 24. As the exhaust gases 20 flow through the gas turbine 22, the exhaust gases 20 force turbine blades to rotate a shaft 26 on an axis of the gas turbine system 10. As illustrated, the shaft 26 may be connected to various components of the gas turbine system 10, including a load 28. The load 28 may be part of a vehicle or a stationary load, such as a propeller on an aircraft or an electric generator in a power plant. The load 28 may include any suitable device capable of being driven by the rotating output of the gas turbine system 10. The shaft 26 may also be connected to the compressor 30.The compressor 30 also includes rotor blades connected to the shaft 26. As the shaft 26 rotates, the rotor blades within the compressor 30 also rotate, compressing air 32 from an air inlet 34 through the compressor 30 and into the fuel nozzles 12 and / or the combustor 18. As described in more detail below, a portion of the compressed air 16 may be bleeded through a bleed air system 36 as a bleed air flow for various purposes. The bleed air flow may be directed through the bleed air system 36 to vent excess pressure generated by the compressor, to protect the combustor 18 and / or the gas turbine 22 from stall or surge conditions, to cool the exhaust gases 20 and / or the gas turbine 22, to dilute or entrain the exhaust gases 20 through the exhaust outlet 24, and the like.

[0033] Fig. 2 illustrates one embodiment of the bleed air system 36. The illustrated bleed air system 36 includes a valve 38 and a staged bleed air line 40. The bleed air system 36 is configured to direct a bleed air flow 42 from a high pressure region 44 (e.g., the compressor 30) to a low pressure region 46 (e.g., the exhaust outlet 24). The valve 38 is fluidly connected to the high pressure region 44 to allow the bleed air flow 42 to flow through the staged bleed air line 40. The bleed air flow 42 is a portion (e.g., less than about 5, 10, 15, 20, or 25 percent) of the main flow 48. For example, the main flow 48 may be the compressed air 16 from the compressor 30, and the bleed air flow 42 may be a diverted portion of the main flow 48.The valve 38 is configured to open to allow the bleed air flow 42 to flow from an inlet 50 of the staged bleed air line 40 to an outlet 52 of the staged bleed air flow 40. The outlet 52 is configured to direct the bleed air flow 42 into the low-pressure region 46. In some embodiments, the low-pressure region 46, such as the exhaust outlet 24, includes a wall 54 opposite the outlet 52. The exhaust outlet 24 may be configured to direct the bleed air flow 42 for any application, such as dilution and entrainment of exhaust gases or cooling of turbine blades.

[0034] A controller 55 coupled to valve 38 may be configured to control the mass flow rate of bleed air flow 42 through staged bleed air line 40. Controller 55 includes memory and a processor. The memory may be a machine-readable medium configured to store code or instructions that can be used by the processor to control valve 38. Opening valve 38 allows a larger bleed air flow 42 to flow through staged bleed air line 40. Valve 38 may be fully closed to substantially prevent bleed air flow 42 from passing through staged bleed air line 40.Adjusting valve 38 sets bleed air flow 42 as a portion of main flow 48 such that opening valve 38 increases bleed air flow 42 and decreases main flow 48, and closing valve 38 decreases bleed air flow 42 and increases main flow 48. In some embodiments, bleed air flow 42 may be set to a portion between approximately 0% to 15%, 1% to 10%, or 4% to 8% of main flow 48. Valve 48 may be a valve of any design, including, but not limited to, a butterfly valve, a spool valve, a poppet valve, or a check valve.

[0035] The bleed air flow 42, which is branched off from the main flow 48 of the high-pressure region 44, is at a higher pressure than the surroundings of the low-pressure region 46. The high-pressure region 44 has a first pressure, and the low-pressure region 46 has a lower second pressure. The bleed air flow 42 may flow rapidly from the inlet 50 at approximately the first pressure to the outlet 52 at approximately the second pressure. The rapid flow of the bleed air flow 42, as its pressure drops, may generate vibrations and noise within the bleed air system 36 unless otherwise mitigated as described herein. For example, throttling the bleed air flow 42 with the valve 38 may cause disturbances in the bleed air flow 42 that cause vibrations and noise due to cavitation, backpressure waves, or other effects due to the pressure reduction.Currently contemplated embodiments of the bleed air system 36 are configured to reduce vibration and noise by lowering the pressure of the bleed air flow 42 in multiple stages (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, or more stages). Reducing vibration and noise can reduce fatigue, increase service life, and reduce maintenance of the bleed air system 36, the high-pressure region 44 (e.g., the compressor 30), and / or the low-pressure region 46 (e.g., the exhaust outlet 24). Each stage of the bleed air system 36 can be configured to lower the pressure of the bleed air flow 42 to reduce vibration and noise.In some embodiments, the bleed air system 36 is configured to reduce the vibration and noise from the progressively depressurized bleed air flow 42 without significantly affecting the mass flow range of the bleed air flow 42 that can be directed by the controller 55 through the valve 38. In some embodiments, each stage is configured to adapt the expansion of the bleed air flow 42 to disturbances inherent in the direction in which the control valve 38 opens to reduce the vibration and noise.

[0036] A rapid depressurization of a flow from a high first pressure to a low second pressure can induce vibrations and noise by creating pressure waves. Slowing the rate of depressurization of the flow and / or gradually decreasing the pressure of the flow can reduce the flow-induced vibrations and noise by reducing the magnitude of the pressure waves. For example, a depressurization of the flow from the first pressure to the second pressure over a short length of piping can induce a larger pressure wave than a depressurization of the same flow from the first pressure to the second pressure over a longer length of piping. Reducing the vibration of the bleed air vibration 42 can reduce wear on the valve 38, the bleed air line 40, the outlet 52, and / or other parts of the gas turbine system 10.Reducing vibrations can increase the lifespan of the valve 38 and the bleed air line 40. Some of the factors that affect the pressure of flow through a pipeline (e.g., the bleed air flow 42 through the staged bleed air line 40) include friction, length of flow, nominal diameters (e.g., pipeline diameter), and obstructions in the flow (e.g., valves, orifice plates, bends). Increasingly lowering the pressure of the flow in stages can reduce the amplitude of the pressure waves to reduce vibrations and noise of the pipeline (e.g., the staged bleed air line 40) and any components coupled thereto. The stages can be configured to disperse the pressure waves to further reduce vibrations and noise. In some embodiments, the pressure ratio between stages (e.g., second-stage pressure / first-stage pressure) is greater than approximately 0.528, which is the critical pressure for air.Maintaining the pressure ratio between stages above the critical pressure ratio can reduce the likelihood of supersonic flow and pressure waves that can cause vibration and noise.

[0037] The stepped bleed air line 40 contains two or more stages 56 to reduce the pressure of the bleed air flow 42. Although Fig. 2 shows two stages 56 and one inlet, other embodiments may include between about 2 and 15 stages, about 3 to 10 stages, or about 4 to 8 stages, or any portion therein. In some embodiments, a first stage 58 is connected to the inlet 50, and a second stage 60 is interposed between the first stage 58 and the outlet 52. The inlet 50 has an inlet length 62 and an inlet dimension 64, while the first stage 58 has a first length 66 and a first dimension 68, and the second stage 60 has a second length 70 and a second dimension 72. The stepped bleed air line 40 may have a variable dimension 74 (e.g., a variable diameter) from the inlet 50 to the outlet 52. In some embodiments, the stepped bleed air line 40 has a circular cross-section 76.When the cross-section 76 is a circle, the characteristic dimensions, such as the inlet dimension 64, the first dimension 68, and the second dimension 72, are diameters of the inlet 50, the first step 58, and the second step 60, respectively. Alternatively, the cross-section 76 may have the shape of an oval, a rectangle, a hexagon, or other polygon, and each of the dimensions may be a side length or another characteristic dimension of the cross-section 76. In some embodiments, the cross-section 76 may vary between the steps 56 of the stepped bleed air line 40. For example, the inlet 50 may have a rectangular cross-section 76, while the first step 58 may have a circular cross-section 76, and the second step 60 may have an oval cross-section 76.

[0038] The length and characteristic dimension of the inlet 50 and each stage 56 may be configured to gradually reduce the pressure of the bleed air flow 42 to reduce the vibration and noise of the bleed air system 36. In some embodiments, the length and characteristic dimension for the inlet 50 or a stage 56 may be configured such that the bleed air flow 42 fully develops before flowing to the next stage 56 or to the outlet 52. A fully developed flow has a substantially stable velocity profile across the cross-section 76. In some embodiments, the length and characteristic dimension of the inlet 50 or a stage 56 may be configured in a particular relationship to one another.For example, the first length 66 may be approximately 3.5 to 4.5 times greater than the first dimension 68, and / or the second length 70 may be approximately 3.5 to 4.5 times greater than the second dimension 72. In some embodiments, the ratio between the inlet length 62 and the inlet dimension 64 is approximately 3.06, while the ratio between the first length 66 and the first dimension 68 is approximately 4.12, and the ratio between the second length 70 and the second dimension 72 is approximately 4.02.

[0039] The stepped bleed air line 40 may be configured to lower the pressure of the bleed air flow 42 in each stage 56 by expanding as it passes through an expansion section 78 (e.g., a conical line) and / or to reduce the kinetic energy by means of a diffuser plate 80 (e.g., a plate with diffusion holes or orifices 82). An expansion section 78 may be configured to increase the area of the cross-section 76 and reduce the static pressure of the bleed air flow 42. A diffuser plate 80 is configured to impede the bleed air flow 42 and reduce the dynamic pressure of the bleed air flow 42 by reducing the kinetic energy of the bleed air flow. The orifices 82 through the diffuser plate 80 allow the bleed air flow 42 to flow through the diffuser plate 80.The stepped bleed air line 80 may include a plurality of stages 56, with each stage 56 having an expansion section 78 or one or more diffuser plates 80, or combinations thereof. Some embodiments of the stepped bleed air line 40 are configured to utilize both expansion sections 78 and diffuser plates 80 to reduce the pressure (e.g., static pressure and dynamic pressure) of the bleed air flow 42 to reduce vibrations. The expansion sections 78 and the diffuser plates 80 may be disposed in the stepped bleed air line 40 to reduce vibrations of the bleed air system 36 based at least in part on the mass flow rate, pressure, and kinetic energy of the bleed air flow 42 through the stepped bleed air line 40. For example, some embodiments may include two stages 56 with an inlet 50, two expansion sections 78, and three diffuser plates 80, as shown in FIG. Fig. 2. Other embodiments may include multiple stages 56 (e.g., two, three, four, five, or more) with an inlet 50 and three or more diffuser plates 80. Other configurations of the presently contemplated embodiments include more than two stages 56 and other numbers of expansion sections 78 and / or diffuser plates 80.

[0040] In some embodiments, each step 56 may include an expansion section 78. For example, the stepped bleed air line 40 may include the inlet 50, the first stage 58 with a first expansion section 84 having a first width 86, the second stage 60 with a second expansion section 88 having a second width 90, and the outlet 52. The expansion section 78 increases the variable dimension 74 (e.g., diameter) of the stepped bleed air line 40 in the downstream direction toward the outlet 52. Each expansion section 78 connects a step 56 having a relatively large characteristic dimension to the inlet 50 or to another step 56 having a relatively small characteristic dimension. Each expansion section 78 has a percentage of expansion that is a measure of the increase in the characteristic dimension (e.g., from the first dimension 68 to the second dimension 72).The percentage of expansion of each expansion section 78 may be based on how the stepped bleed air line 40 is configured to reduce vibration and noise. For example, the first expansion percentage of the first expansion section 84 and the second expansion percentage of the second expansion section 88 may be approximately 25%. In some embodiments, one expansion section 78 of a stepped bleed air line 40 has a different expansion percentage than another expansion section 78 of the same stepped bleed air line 40. The expansion percentage may be between approximately 5 and 50%, 10 and 40%, or 20 and 30%, or any subrange therein. In some embodiments, the width of each expansion section may be a portion between 75 and 100% of the upstream characteristic dimension.For example, the first width 86 may be approximately 95% of the inlet dimension 64, and the second width 90 may be approximately 88% of the first dimension 68.

[0041] As described above, an expansion section 78 is configured to expand the bleed air flow 42 to reduce the static pressure. In some embodiments, the stages 56 of the stepped bleed air line 40 may include only expansion sections 78 without any diffuser plates 80. As shown in Fig. 2, the variable dimension 74 of the stepped bleed air line 40 increases at each expansion section 78 from the inlet 50 to the outlet 52. The variable dimension 74 of the stepped bleed air line 40 may have three different values between the inlet 50 and the outlet 52. For example, the stepped bleed air line 40 may have an inlet dimension 64 that is smaller than the first dimension 68, which is smaller than the second dimension 72. The inlet 50 and each step 56 are configured to allow the bleed air flow 42 to flow in a substantially axial direction 92 along the stepped bleed air line 40. In some embodiments, the inlet 50 lies along an inlet axis 94, while the first step 58 lies along a first axis 96, and the second step 60 lies along a second axis 98. The inlet axis 94, the first axis 96 and the second axis 98 may form the same axis or parallel axes.In some embodiments, the inlet 50, the first stage 58, and the second stage 60 may be concentric. As shown in . Fig. 2, the inlet 50, the first stage 58, and the second stage 60 may not be axisymmetric. As defined herein, the inlet, first, and second axes 94, 96, and 98 are offset parallel axes, wherein the axes 94, 96, and 98 are parallel to each other and the bleed air flow 42 is not redirected (e.g., constricted) by a downstream stage. The inlet 50, the first stage 58, and the second stage 60, as shown in Fig. 2 have offset parallel axes 94, 96, and 98. The offset parallel axes 94, 96, 98 may be offset from each other in the same radial direction so that the stepped bleed air line 40 opens in the axial direction.

[0042] In some embodiments, as in Fig. 2, the stepped bleed air line 40 is straight with parallel axes 94, 96, and 98. Alternatively, some embodiments may include one or more steps 56 that are not parallel to the inlet 50 and outlet 52. Fig. 3 illustrates one embodiment of a stepped bleed air line 40 in which the first axis 96 of the first stage 58 is oriented perpendicular to the inlet axis 94 or the second axis 98. Other embodiments may include non-parallel stages (e.g., the first stage 58) with axes at different angles 97 to the axial direction 92, including approximately 15°, 30°, 45°, 60°, 75°, or 90°. Elbows 99 connect the non-parallel stage (e.g., the first stage 58) to the inlet or other stages 56. The one or more elbows 99 may be configured to reduce the kinetic energy and pressure of the bleed air flow 42. As will be appreciated, the length (e.g., the first length 66) of the non-parallel stage may be configured to stabilize the bleed air flow 42 before it enters the next pipe bend 99 or stage 56.

[0043] Returning to Fig. 2, in some embodiments, the steps 56 of the stepped bleed air line 40 may include only diffuser plates 80. The diffuser plates 80 include a plurality of orifices 82 configured to condition the bleed air flow 42 as it passes through the stepped bleed air line 40. In some embodiments, the diffuser plate 80 may include an outer row of orifices 82 arranged around a central orifice 100. Each of the orifices 82 has an orifice dimension 102 (e.g., a diameter). In some embodiments, each orifice 82 is substantially the same size with the same orifice dimension 102. In other embodiments, the orifice dimension 102 is related to the variable dimension 74 on the diffuser plate 80. The diffuser plates 80 may be arranged in the initial section, the middle section and / or the end section of a stage 56.For example, a first diffuser plate 104 may be disposed in the initial portion of the first stage 58, a second diffuser plate 106 may be disposed in the initial portion of the second stage 60, and a third diffuser plate 108 may be disposed in the final portion of the second stage 60 at the outlet 52. The plurality of apertures 82 of each diffuser plate 80 may be configured to reduce the kinetic energy of the bleed air flow 42 and to reduce vibrations of the stepped bleed air line 42 and / or the wall 54. For example, the diffuser plates 80 may be arranged along the stepped bleed air line 40 based on the variable dimension 74 and the distance to the valve 38 to reduce vibrations. The arrangement of the diffuser plates 80 may be configured to reduce the kinetic energy of the bleed air flow 42 in stages in order to gradually lower the pressure of the bleed air flow 42.

[0044] Some embodiments of the stepped bleed air line 40 may include both expansion sections 78 and diffuser plates 80. The number of stages 56, expansion sections 78, and diffuser plates 80 may be related to each other according to the following mathematical relationships: N=X D=N+1 where N is the number of stages 56, X is the number of expansion sections 78 and D is the number of diffuser plates 80. The stepped bleed air line 40 according to Fig. 2 shows these relationships (1) and (2). The expansion sections 78 and the diffuser plates 80 may be configured based on these relationships (1) and (2) to progressively lower the pressure of the bleed air flow 42 and reduce vibration and noise of the gas turbine system 10. As discussed above, the diffuser plates 80 may be disposed in the initial section, the middle section, and / or the final section of each stage 56 of the stepped bleed air line 40. Other embodiments of the stepped bleed air line 40 may have numbers of stages 56, expansion sections 78, and diffuser plates 80 that differ from those defined in relationships (1) and (2). Currently contemplated embodiments include stepped bleed air lines 40 with a larger number of stages 56 for larger pressure differentials between the high-pressure region 44 and the low-pressure region 46.

[0045] Fig. 4 illustrates an embodiment of a diffuser plate 80 having a plurality of apertures 82. As explained above, the diffuser plate 80 may have a circular cross-section 76. Embodiments of the diffuser plate 80 may have between approximately 2 and 100, approximately 5 to 50, or approximately 7 to 20 apertures 82, or any portion therein. Each of the apertures 82 may have the shape of a circle, a rectangle, a slot, an X-shape, a V-shape, a triangle, a polygon, or another geometric shape. The apertures 82 may be arranged in various configurations, for example, in concentric rows, in a grid pattern, or in a pattern matching the cross-section 76 (e.g., circular). For example, the diffuser plate 80 of FIG. Fig. 4, a first row or ring 110 of orifice openings 82, a second row or ring 112 of orifice openings 82, and a third row or ring 114 of orifice openings 82 in a substantially concentric arrangement. Other embodiments may have more or fewer rows of orifice openings 82. In some embodiments, the diffuser plate 80 may have an orifice opening 82 around a centerline 116 of the diffuser plate 80. The diffuser plate 80 is configured to inhibit and reduce the kinetic energy of the bleed air flow 42 through the stepped bleed air line 40. Some configurations of the diffuser plate 80 may reduce the kinetic energy and lower the pressure of the bleed air flow 42 more than other configurations.As such, the configuration of the plurality of apertures 82 is configured to reduce vibration and noise of the staged bleed air line 40 and / or other portions of the gas turbine system 10. For example, a diffuser plate 80 having a first configuration may be disposed in the first stage 58, and a diffuser plate 80 having a different second configuration may be disposed in the second stage 60.

[0046] In some embodiments, the configuration of the plurality of apertures 82 is based at least in part on the variable dimension 74 (e.g., diameter) of the stepped bleed air conduit 40 on the diffuser plate 80. For example, the aperture dimension 102 may be approximately 28% of the variable dimension 74. In some embodiments, the aperture dimension 102 may be between approximately 10 and 40%, approximately 15 and 30%, or approximately 20 and 25% of the variable dimension 74, or any subrange therein.

[0047] The number of orifices 82 established through the diffuser plate 80 is based, at least in part, on the effect of the orifices 82 on the bleed air flow 42, such as the vibrations and / or noise induced or reduced by the orifices 82. In some embodiments, the diffuser plate 80 has only a large number of small orifices 82 (e.g., sized relatively like the second row 112). In other embodiments, the diffuser plate 80 has only a small number of larger orifices 82 (e.g., sized relatively like the first row 110). The number and size of the orifices 82 affect the mass flow rate of the bleed air flow 42 through the diffuser plate 80. The plate surface 118 obstructs the bleed air flow 42, and the orifices 82 allow the bleed air flow 42 to pass.In some embodiments, the total area of the apertures 82 may be between approximately 35 and 75%, approximately 45 and 65%, or approximately 50 and 60% of the cross-sectional area where the diffuser plate 80 is located. For example, a location of the stepped bleed air line 40 with a variable dimension 74 (e.g., a variable diameter) of approximately 10 cm has a circular cross-sectional area of approximately 78.54 cm. 2 For a diffuser plate 80 having seven circular apertures 82 arranged at this location, where the aperture dimensions 102 (e.g., diameter) are approximately 28.5% of the variable dimension 74 (i.e., 2.85 cm), the total area of the apertures 82 may be approximately 44.66 cm 2or approximately 57% of the circular cross-sectional area of the stepped bleed air line 40 at this location. This example is intended to clearly demonstrate a relationship between the variable dimension 74 and the number and size of the orifices 82 in some embodiments. The stepped bleed air line 40 and the diffuser plate 80 are not intended to be limited to the sizes and configurations of this example. Other embodiments of the stepped bleed air line 40 and the diffuser plates 80 may have different variable dimensions 74, different orifice dimensions 102, and different numbers of orifices 82.

[0048] In some embodiments, the aperture dimension 102 for the apertures 82 of different diffuser plates 80 is based on the same relationship to the variable dimension 74 on each respective diffuser plate 80. For example, the first diffuser plate 94 may be Fig. 2, a variable dimension 74 (e.g., a diameter) of approximately 10 cm and an aperture dimension 102 (e.g., a diameter) of approximately 2.5 cm (i.e., approximately 25% of 10 cm). The second diffuser plate 96 may have a variable dimension 74 of approximately 12.5 cm and an aperture dimension 102 of approximately 3.13 cm (i.e., approximately 25% of 12.5 cm). In further embodiments, the aperture dimension 102 is the same for the apertures 82 of different diffuser plates 80, regardless of the variable dimension 74 on each respective diffuser plate 80. For example, the first diffuser plate 94 may Fig. 2, a variable dimension 74 (e.g., a diameter) of approximately 10 cm and an aperture dimension 102 (e.g., a diameter) of approximately 2.5 cm (i.e., approximately 25% of 10 cm). The second diffuser plate 96 may have a variable dimension 74 of approximately 12.5 cm and an aperture dimension 102 of approximately 2.5 cm, which is equal to the aperture dimension 102 of the first diffuser plate 94. In some embodiments, the second diffuser plate 96 may have the same number or more apertures 82 than the first diffuser plate 94.

[0049] In some embodiments, the apertures 82 of each diffuser plate may have different aperture dimensions 102 based on the arrangement on the diffuser plate 80. For example, as in Fig. 4, the first row 110 may be larger than the second row 112 and the third row 114. The number of openings 82 in each row may vary between the rows. As shown in Fig. 4, the first row 110 and the second row 112 have eight apertures 82, while the third row 114 has three apertures. The aperture dimension 102, the number of apertures 82, and the configuration of the apertures 82 may be configured with a combination of any of the aperture configurations described above to influence the bleed air flow 42 as it passes through the diffuser plate 80 to reduce vibration and / or noise.

[0050] Technical effects of the invention include that the stepped bleed air line is configured to reduce vibrations and / or noise of the bleed air system, including the valve and / or the exhaust outlet downstream of the bleed air system. A reduction in vibrations can reduce maintenance costs for the bleed air system, the valve, and / or the gas turbine system. A reduction in vibrations can further extend the service life of the gas turbine. The stepped bleed air line is configured to successively (e.g., stepwise) reduce the pressure and kinetic energy of the bleed air flow. The stepped bleed air line can further reduce the likelihood of supersonic flows that can induce pressure waves.Some embodiments of the stepped bleed air line are configured to receive a bleed air flow at a high pressure of approximately 1.72 MPa (250 psia) to 2.41 MPa (350 psia) relative to a significantly lower pressure, such as approximately the pressure of the outside environment. Other configurations of the expansion sections and the diffuser plates of embodiments may be based on the mass flow rate, pressure, and velocity of the bleed air flow of the embodiments. A successive reduction in pressure along the length of the stepped bleed air line may increase the effective area of the outlet more than increasing the dimension (e.g., diameter) of the bleed air line at the outlet alone and / or disposing a diffuser plate at the outlet alone.The stepped bleed air line can be used for bleed air flows from a compressor or other system that discharges a highly pressurized flow into a low pressure area.

[0051] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims and may include other examples that occur to those skilled in the art. Such other examples are intended to be included within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

[0052] A system includes a bleed air system configured to direct a bleed air flow from a high-pressure region to a low-pressure region. The bleed air system includes a valve configured to control the bleed air flow as it passes through the bleed air system and a staged bleed air line configured to progressively decrease the pressure of the bleed air flow. The staged bleed air line includes an inlet coupled to the valve, a first stage configured to decrease the pressure of the bleed air flow and coupled to the inlet, a second stage configured to decrease the pressure of the bleed air flow and coupled to the first stage, and an outlet coupled to the second stage. The outlet is configured to direct the bleed air flow to the low-pressure region.The inlet, first stage, second stage and outlet are arranged along parallel axes.

Claims

[1] System that has: a bleed air system (36) configured to direct a bleed air flow (42) from a high pressure region (44) to a low pressure region (46), the bleed air system (36) comprising: a valve (38); and a stepped bleed air line (40) configured to progressively lower the pressure of the bleed air flow (42), the stepped bleed air line (40) comprising: an inlet (50) coupled to the valve (38); a first stage (58) coupled to the inlet (50), the first stage (58) configured to reduce the pressure of the bleed air flow (42); a second stage (60) coupled to the first stage (58), the second stage (60) being configured to reduce the pressure of the bleed air flow (42); and an outlet (52) coupled to the second stage (60), the inlet (50) and the outlet (52) being arranged along parallel axes, a first expansion section (84) coupled between the inlet (50) and the first stage (58), the first expansion section (84) having a first percentage of expansion, a second expansion section (88) coupled between the first stage (58) and the second stage (60), the second expansion section (88) having a second percentage of expansion, each step having a constant dimension along its longitudinal extent, wherein the stepped bleed air line (40) has at least one diffuser plate (80) configured to reduce the pressure of the bleed air flow (42), and wherein the at least one diffuser plate (80) is arranged at the inlet (50), the first stage (58), the second stage (60), or the outlet (52), or a combination thereof. [2] The system of claim 1, wherein at least one of the first stage (58) and the second stage (60) is / are configured to lower the pressure of the bleed air flow by expansion, and wherein the inlet (50), the outlet (52), the first stage (58) and the second stage (60) are arranged along parallel axes. [3] The system of claim 1, wherein at least one of the first stage (58) and the second stage (60) is / are configured to reduce the pressure of the bleed air flow (42) by expansion; and / or wherein a first diffuser plate (94) of the at least one diffuser plate (80) is disposed in the stepped bleed air line (40) at a first location having a first cross-sectional area, and the first diffuser plate (94) has a plurality of orifices having a total orifice area, the total orifice area being greater than 40% of the cross-sectional area; and / or wherein each diffuser plate (80) of the at least one diffuser plate (80) has a plurality of orifices (82), and each of the plurality of orifices (82) has a common dimension;and / or wherein each diffuser plate (80) of the at least one diffuser plate (80) has a plurality of apertures (82), and a size of the plurality of apertures (82) is based at least in part on a dimension of the stepped bleed air line (40) at a location on the respective diffuser plate (80); [4] The system of claim 1, wherein the parallel axes consist of a common axis. [5] The system of claim 1, wherein the bleed air system (36) is configured to reduce vibrations within the valve (38) or the stepped bleed air line (40). [6] The system of claim 1, comprising: the high-pressure region (44), wherein the high-pressure region (44) has a compressor (30); and a gas turbine (22) coupled to the compressor (30). [7] The system of claim 6, wherein the compressor (30) is configured to produce a compressed air flow and the bleed air flow (42), and the valve (38) is configured to control the bleed air flow to less than about 10% of the compressed air flow. [8] System that has: a bleed air system (36) configured to direct a bleed air flow (42) from a high pressure region (44) to a low pressure region (46), the bleed air system (36) comprising: a stepped bleed air line (40) configured to progressively lower the pressure of the bleed air flow (42), the stepped bleed air line (40) having a variable line dimension, and the stepped bleed air line (40) comprising: an inlet (50) configured to be coupled to the high pressure region (44), the inlet (50) having an inlet dimension (64); a first stage (58) coupled to the inlet (50), the first stage (58) having a first dimension (68) greater than the inlet dimension (64), and the first stage (58) configured to lower the pressure of the bleed air flow (42) by expansion; a second stage (60) coupled to the first stage (58), the second stage (60) having a second dimension (72) greater than the first dimension (68), and the second stage (60) configured to lower the pressure of the bleed air flow (42) by expansion; and an outlet (52) coupled to the second stage (60), the inlet (50), the first stage (58), the second stage (60) and the outlet (52) being arranged along parallel axes, a first expansion section (84) coupled between the inlet (50) and the first stage (58), the first expansion section (84) having a first percentage of expansion, a second expansion section (88) coupled between the first stage (58) and the second stage (60), the second expansion section (88) having a second percentage of expansion, each step having a constant dimension along its longitudinal extent, wherein the stepped bleed air line (40) has at least one diffuser plate (80) configured to reduce the pressure of the bleed air flow (42), and wherein the at least one diffuser plate (80) is arranged at the inlet (50), the first stage (58), the second stage (60), or the outlet (52), or a combination thereof. [9] System that has: a gas turbine system (10) comprising: a compressor (30) configured to generate a bleed air flow (42); a gas turbine (22) coupled to the compressor (30); an exhaust outlet (24) configured to receive an exhaust gas flow (20) and the bleed air flow (42); and a bleed air system (36) configured to direct the bleed air flow (42) from the compressor (30) to the exhaust outlet (24), the bleed air system (36) comprising: a stepped bleed air line (40) configured to progressively lower the pressure of the bleed air flow (42), and comprising: an inlet (50) coupled to the compressor (30), the inlet (50) having an inlet diameter; a first stage (58) coupled to the inlet (50), the first stage (58) having a first diameter greater than the inlet diameter, and the first stage (58) configured to reduce the pressure of the bleed air flow (42) by expansion; a second stage (60) coupled to the first stage (58), the second stage (60) having a second diameter that is greater than the first diameter, and the second stage (60) configured to reduce the pressure of the bleed air flow (42) by expansion; and an outlet (52) coupled to the second stage, the outlet configured to direct the bleed air flow (42) to the exhaust outlet (24), and the inlet (50), the first stage (58), and the outlet (52) being arranged along parallel axes; and at least one diffuser plate (80) configured to reduce the pressure of the bleed air flow (42), a first expansion section (84) coupled between the inlet (50) and the first stage (58), the first expansion section (84) having a first percentage of expansion, a second expansion section (88) coupled between the first stage (58) and the second stage (60), the second expansion section (88) having a second percentage of expansion, each step having a constant dimension along its longitudinal extent, wherein the stepped bleed air line (40) has at least one diffuser plate (80) configured to reduce the pressure of the bleed air flow (42), and wherein the at least one diffuser plate (80) is arranged at the inlet (50), the first stage (58), the second stage (60), or the outlet (52), or a combination thereof.

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