System and method for combining compressor bleed air and ventilation flows in a gas turbine engine - Patents.com

Abstract

To provide a system and method for combining a compressor bleed flow and a ventilation flow of a gas turbine engine.SOLUTION: A flow combiner (12) is provided for a gas turbine engine (50). The flow combiner (12) includes an outlet duct (14), a compressor bleed inlet duct (16) coupled to the outlet duct (14), and a ventilation inlet duct (18) coupled to the outlet duct (14). The compressor bleed inlet duct (16) is configured to receive a bleed flow (28) from a compressor (56) of the gas turbine engine (50). The ventilation inlet duct (18) is configured to receive a ventilation flow (36) from an enclosure (54) surrounding the gas turbine engine (50). The bleed flow (28) and the ventilation flow (36) are combined as an outlet flow through the outlet duct (14).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The subject matter disclosed herein relates to gas turbine engines, and more particularly to systems and methods for combining compressor bleed and ventilation flows of gas turbine engines. [Background technology]

[0002] Gas turbine engines generally include a compressor, a combustor, and a turbine. The combustor combusts fuel with compressed air from the compressor and supplies hot combustion gases to a turbine to drive a load, such as a generator. Gas turbine engines may discharge multiple flows (e.g., exhaust gas flow, ventilation flow, compressor bleed flow, etc.) through separate flow paths, such as stacks. Unfortunately, each stack requires space and adds cost to the gas turbine engine. Each stack may also include various internal components, such as silencer baffles. As a result, gas turbine engines may have dual sections (e.g., stack, silencer baffles, etc.) to handle the multiple flows. Summary of the Invention

[0003]

[0013] Several embodiments commensurate in scope 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 only to provide a brief outline of possible forms of the invention. Of course, the invention may encompass a variety of forms that may be similar to or different from the embodiments described below.

[0004] In a first embodiment, a system includes a combiner in which the bleed flow and the ventilation flow combine as an outlet flow through an outlet duct, the combiner comprising: the outlet duct; a compressor bleed inlet duct coupled to the outlet duct, the compressor bleed inlet duct configured to receive the bleed flow from a compressor of the gas turbine engine; and a ventilation inlet duct coupled to the outlet duct, the ventilation inlet duct configured to receive the ventilation flow from a housing surrounding the gas turbine engine.

[0005] In a second embodiment, a method is provided that includes receiving a bleed air flow from a compressor of a gas turbine engine into a compressor bleed inlet duct coupled to an outlet duct of a flow combiner, and receiving a ventilation flow from a housing surrounding the gas turbine engine into a ventilation inlet duct coupled to the outlet duct, wherein the bleed air flow and the ventilation flow combine as an outlet flow through the outlet duct.

[0006] In a third embodiment, a system includes a combiner in which the high-energy stream and the low-energy stream combine as an outlet stream through an outlet duct, the combiner comprising: the outlet duct; a first inlet duct coupled to the outlet duct, the first inlet duct configured to receive the high-energy stream and comprising an adjustable valve; and a second inlet duct coupled to the outlet duct, the second inlet duct configured to receive the low-energy stream and comprising at least one fan.

[0007] These and other features, aspects, and advantages of the present invention will become better understood from the following detailed description when read in conjunction with the accompanying drawings, in which like reference numerals represent like parts throughout. [Brief explanation of the drawings]

[0008] [Figure 1]FIG. 1 is a schematic block diagram of an embodiment of a gas turbine system having a combiner configured to combine different flows (e.g., a ventilation flow and a compressor discharge flow). [Figure 2] FIG. 2 is a perspective view of an embodiment of the flow junction of FIG. 1. [Figure 3] FIG. 3 is a side view of one embodiment of the flow junction of FIG. 2. [Figure 4] FIG. 3 is a front view of one embodiment of the flow junction of FIG. 2. [Figure 5] FIG. 4 is a perspective view of an embodiment of a backflow suppressor of the confluence shown in FIGS. 1 and 3, further illustrating an embodiment of multiple conduits of the backflow suppressor. [Figure 6] FIG. 2 is a schematic cross-sectional side view of a combiner coupled to the compressor of the gas turbine system of FIG. 1 illustrating a compressor bleed intake conduit having a variable bleed valve configured to regulate compressor bleed air flow to the combiner. [Figure 7] 7 is a flow chart of an embodiment of a method for operating a gas turbine system in different modes using the flow combiner of FIGS. 1-6. DETAILED DESCRIPTION OF THE INVENTION

[0009] One or more specific embodiments of the present invention are described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described herein. It should be appreciated that in the development of any actual implementation, such as any engineering or design project, numerous implementation-specific decisions must be made to achieve the developer's specific goals, including compliance with system- and business-related constraints that may vary from implementation to implementation. Moreover, it should be appreciated that such a development effort may be complex and time-consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill in the art having the benefit of this disclosure.

[0010] When introducing elements of various embodiments of the invention, the articles "a," "an," "the," and "said" are intended to mean that there are one or more of the elements. The terms "comprise," "include," and "have" are intended to be inclusive and mean that there may be additional elements other than the listed elements.

[0011] As described in more detail below, the present embodiments described herein provide an efficient ventilation system that combines a ventilation flow from a housing disposed around a gas turbine engine with a bleed flow from the compressor of the gas turbine engine via a flow combiner. Without the disclosed flow combiner, a gas turbine engine might include many duplicate sections (e.g., separate stacks and assemblies of silencers) for various discharge flows, such as the ventilation flow, the compressor bleed flow, and other flows. These duplicate sections result in greater space consumption, greater installation costs, and greater maintenance costs. Unfortunately, the various discharge flows of a gas turbine engine can have significantly different flow rates, pressures, temperatures, and / or other characteristics during various operational phases of the gas turbine engine (e.g., startup, steady state, shutdown, part load, full load, etc.).

[0012] Thus, the system described herein is a combined ventilation system and silencer for attenuating noise from combined ventilation and bleed air flows. By combining the flows and using a single silencer assembly, the ventilation system described herein can reduce component and maintenance costs, thereby improving the efficiency of the gas turbine system. To effectively combine the flows, the bleed air flow and ventilation air flow may be adjusted based on various operating modes of the gas turbine system. For example, during a start-up mode, the bleed air flow may be increased but set at a low flow rate, and the ventilation air flow may be operating at full flow. During a full-load mode, the bleed air flow may be closed, but the ventilation air flow may be operating at full flow. Meanwhile, during a normal shutdown mode, the bleed air flow may be operating at a moderate flow rate, but the ventilation air flow may be operating at full flow. Furthermore, during an emergency shutdown or load reduction mode, the bleed air flow may be operating at maximum flow rate, and the ventilation air flow may be operating at a reduced flow rate. Combining the ventilation flow and the bleed flow includes continuously or cyclically adjusting the flow rate of each flow to meet the specific operating requirements of each mode. A combiner that allows the bleed and ventilation flows to mix includes two distinct channels. One channel may be designated as an inlet for the ventilation flow to enter the combiner, and the other channel may be designated as an inlet for the bleed flow to enter the combiner. After both the ventilation flow and the bleed flow enter the combiner through their respective channels, both flows can mix within the combiner. In particular, the ventilation flow channel may include a collection of conduits that help inhibit backflow and help distribute the ventilation flow within the combiner.

[0013] 1 is a schematic block diagram of a gas turbine system 10 having a flow combiner 12 configured to combine different flows. The different flows may have substantially different flow rates, pressure temperatures, and fluid compositions. In the illustrated embodiment, the different flows may correspond to a compressor bleed flow and a ventilation flow. In particular, as described in more detail below, the flow combiner 12 includes an outlet duct 14, a first inlet duct 16 (e.g., a compressor bleed inlet duct) coupled to the outlet duct 14, and a second inlet duct 18 (e.g., a ventilation inlet duct) coupled to the outlet duct 14.

[0014] As shown, the first inlet duct 16 and the second inlet duct 18 join to a common duct portion 20 of the outlet duct 14. In some embodiments, the common duct portion 20 may include a confluence (or mixing) section 22 having one or more flow mixers 24 (e.g., backflow suppressors, flow baffles, flow dividers, flow conduits, etc.). For example, the one or more flow mixers 24 may include a backflow suppressor 32 having a plurality of conduits 34 (e.g., a bundle of conduits) that converge in a downstream direction of the fluid flows (e.g., compressor bleed flow 28 and ventilation flow 36) from the first inlet duct 16 and the second inlet duct 18. The backflow suppressor 32 (e.g., conduits 34) is configured to suppress reverse flow of the fluid flow (e.g., from the first inlet duct 16 to the second inlet duct 18, or vice versa). The backflow suppressor 32 may also be configured to induce mixing of the fluid flows (e.g., 28, 36) within the common duct portion 20. The first inlet duct 16 may include or be fluidly coupled to a variable valve 26 (e.g., a variable bleed valve) configured to vary the fluid flow 28 (e.g., compressor bleed flow) entering the first inlet duct 16. The variable valve 26 may be adjustable between open and closed positions (e.g., to increase or decrease flow rate, pressure, etc.) to help control the admission of the fluid flow 28 into the merger 12, reduce backflow of the fluid flow 28 into the second inlet duct 18, and improve mixing in the outlet duct 14. For example, the variable valve 26 may include multiple adjustable valve elements 30 (e.g., rotatable doors or flaps).

[0015] The second inlet duct 18 may include a damper 31 configured to open in response to a fluid flow 36 (e.g., a ventilation flow) and close in response to cessation of the fluid flow 36. The damper 31 may be a gravity damper configured to close one or more pivoting doors (e.g., one, two, three, four, five, or more hinged damper doors) by gravity when the fluid flow 36 halts. Alternatively, the damper 31 may be a spring-loaded damper configured to bias the pivoting doors toward a closed position such that the fluid flow 36 opens the pivoting doors when the force of the fluid flow 36 is sufficient to overcome the spring force. The damper 31 may also be configured to inhibit backflow of the fluid flow 28 into the second inlet duct 18 relative to the incoming fluid flow 36. The second inlet duct 18 may also include at least one fan 38 (e.g., one, two, or three fans) configured to force the fluid stream 36 into the second inlet duct 18. The damper 31 may be configured to open in response to operation of the fan 38 (i.e., when the fan is turned on) and to close when the fan 38 stops operating (i.e., when the fan is turned off). The speed of the fan 38 may be adjustable (e.g., increased or decreased) to help control the intake of the fluid stream 36, reduce backflow of the fluid stream 28 relative to the fluid stream 36, and improve mixing of the fluid streams 28 and 36 in the outlet duct 14.

[0016] The fluid streams 28 and 36 combine in the converging section 22 as a converging fluid stream 40, which then passes through a silencer section 42 in the outlet duct 14. The silencer section 42 may include a plurality of silencer baffles 44 (e.g., parallel silencer baffles) extending downstream of the converging fluid stream 40. The silencer baffles 44 are configured to reduce noise associated with the fluid streams 28, 36, and 40 passing through the converging section 12. For example, each silencer baffle 44 may include an outer housing (e.g., a perforated wall) and an internal sound-absorbing structure (e.g., sound-absorbing material, a chamber, a passageway, a baffle, etc.). Each silencer baffle 44 may be elongated in the downstream direction and may include an aerodynamic shape (e.g., an airfoil shape). The outlet duct 14 and silencer section 42 (e.g., silencer baffle 44) may be designed to handle the maximum expected loads (e.g., flow rate, pressure, temperature, noise, etc.) for both the compressor bleed flow 28 and the ventilation flow 36.

[0017] In the illustrated embodiment, the combiner 12 is used to combine two different streams (e.g., streams having different energy levels) from the gas turbine system 10. In some embodiments, the combiner 12 may be configured to combine any number (e.g., 2, 3, 4, 5, 6, or more) different streams from the gas turbine system 10 or any other system that generates different streams (e.g., different flow rates, pressures, etc.). For example, the different streams may be described as a high-energy stream and a low-energy stream, where the high-energy stream has a relatively higher pressure, a relatively higher temperature, and / or a relatively higher flow rate than the low-energy stream. In the illustrated embodiment, the compressor bleed stream 28 may be described as a high-energy stream, and the ventilation stream 36 may be described as a low-energy stream. Thus, the use of “high-energy” and “low-energy” with respect to streams (e.g., high-energy stream and low-energy stream) may be used simply as a relative comparison of the streams. For example, the high-energy stream may have a pressure, temperature, and / or flow rate that is greater than the low-energy stream by a certain percentage or factor (e.g., 1.1, 1.2, 1.3, 1.4, 1.5, 2, 2.5, 3, 4, 5, 10, 20, 30, 40, 50, or more). If additional streams combine within combiner 12, combiner 12 may include additional inlet ducts similar to inlet ducts 16 and 18. However, in the following discussion, combiner 12 will be described in the context of two combined streams from gas turbine system 10, more specifically, a compressor bleed stream as fluid stream 28 and a ventilation stream as fluid stream 36.

[0018] The gas turbine system 10 includes a gas turbine engine 50 coupled to a load 52, such as a generator. The gas turbine system 10 may be stationary or mobile, such as a trailer-mounted power plant (e.g., a generator 52 driven by the gas turbine engine 50). The gas turbine system 10 also includes a housing or enclosure 54 disposed around the gas turbine engine 50, such that a ventilated space or volume is disposed around the gas turbine engine 50 inside the enclosure 54. The gas turbine engine 50 includes a compressor section or compressor 56 having one or more compressor stages (e.g., any number from 1 to 30 stages), a combustor section 58 having one or more combustors 60, and a turbine section or turbine 62 having one or more turbine stages (e.g., any number from 1 to 30 stages). Each compressor stage of the compressor 56 includes a plurality of compressor blades configured to compress intake air. Each combustor 60 includes one or more fuel nozzles 64 configured to supply fuel and compressed air 66 from the compressor 56 to a combustion chamber 68, where the fuel is combusted to generate hot combustion gases 70. The hot combustion gases flow through a turbine 62, driving one or more turbine stages to rotate a shaft 72 (e.g., one or more shafts) coupled to the turbine 62, the compressor 56, and the load 52. Each turbine stage of the turbine 62 includes a number of turbine blades that are driven by the hot combustion gases 70. Ultimately, the turbine 62 discharges the hot combustion gases 70 as exhaust gases 74 into and through an exhaust section 76, such as an exhaust duct and / or an exhaust stack.

[0019] The gas turbine system 10 delivers intake air 80 to the housing 54 and the compressor 56 through an air intake system 82. In the illustrated embodiment, the air intake system 82 includes a filter section 84 having one or more air filters 86, an air inlet duct 88 (e.g., a ventilation air intake duct) coupled to the housing 54, and an air inlet duct 90 (e.g., a compressor air inlet duct) coupled to the compressor 56. The air inlet duct 88 couples to an intake port or opening 92 in the housing 54, and the air inlet duct 88 may include one or more fans 94 (e.g., electric motor-driven fans) configured to help push a ventilation air flow 96 into the housing 54. Ultimately, the ventilation flow 96 enters the second inlet duct 18 (e.g., a ventilation inlet duct) of the confluence 12 as the fluid flow 36.

[0020] The air inlet duct 90 couples to (or extends through) an intake port or opening 92 in the housing 54, and the air inlet duct 90 extends into the housing 54 and couples to a compressor inlet 102 of the compressor 56. The air inlet duct 90 is configured to provide a compressor inlet flow 104 to the compressor 56, which then compresses the air for use throughout the gas turbine engine 50. For example, the compressed air 66 may be used for combustion and cooling in the combustor section 58, cooling in the turbine 62, and cooling elsewhere in the gas turbine engine 50. In some embodiments, the compressed air 66 used for cooling may be bled from the compressor 56 at any suitable location (e.g., compressor bleed flow at various stages of the compressor 56). Furthermore, the compressor bleed flow may be discharged from the gas turbine system 10 through the combiner 12.

[0021] In the illustrated embodiment, the first inlet duct 16 (e.g., a compressor bleed inlet duct) of the flow combiner 12 is coupled to a compressor bleed section 110 of the compressor 56. In particular, the first inlet duct 16 may include a compressor bleed intake conduit 112 coupled to an outer wall 114 of the compressor 56 at the compressor bleed section 110. For example, the compressor bleed intake conduit 112 may extend at least partially or entirely circumferentially around the outer wall 114 of the compressor 56, such as at least 180 degrees, 240 degrees, 300 degrees, or 360 degrees around the compressor 56. The compressor bleed intake conduit 112 may include a compressor opening 116 configured to fit around the outer wall 114 of the compressor 56. In some embodiments, the outer wall 114 of the compressor 56 may include one or more compressor bleed openings configured to allow the compressor bleed flow to enter the first inlet duct 16. As described above, the first inlet duct 16 includes a variable valve 26 (e.g., a variable bleed valve (VBV)) having one or more adjustable valve elements 30 (e.g., doors or flaps) configured to adjust the compressor bleed air flow as a fluid flow 28 into the flow confluence 12. The variable valve 26 may include one or more electric actuators, such as a common electric actuator or separate electric actuators, for each of the multiple adjustable valve elements 30.

[0022] The gas turbine system 10, including the variable valve 26, the fan 38, the fan 94, the fuel injection via the fuel nozzles 64, and other operating parameters, may be controlled by a control system 120 having a monitoring system 122 coupled to a controller 124. The monitoring system 122 includes a plurality of sensors 126 (denoted by S) distributed throughout the gas turbine system 10 to monitor various operating conditions. For example, the sensors 126 may measure ambient conditions (e.g., humidity, temperature, etc.) outside the gas turbine system 10. The sensors 126 may measure intake air conditions (e.g., flow rate, temperature, pressure) in the intake system 82. The sensors 126 may measure compressor conditions (e.g., flow rate, temperature, and pressure of the compressed air 66 from the compressor 56 and the compressor bleed air flow 28). The sensors 126 may measure ventilation conditions (e.g., flow rate, temperature, and pressure of the ventilation air flow 96 in the housing 54 and the ventilation flow 36 in the combiner 12). The sensors 126 measure combustion conditions (e.g., fuel flow rate, fuel temperature, fuel pressure, fuel composition, Wobbe index, fuel-air ratio, flame temperature or flame intensity, combustion dynamics, and NO X , SO X The sensors 126 may measure turbine conditions (e.g., the flow rate, temperature, and pressure of the combustion gases 70 in the turbine 62). The sensors 126 may also measure the rotational speed, clearance between the rotating blades and the walls of the compressor 56 and turbine 62, and vibrations of the gas turbine engine 50. The sensors 126 may measure the load of the gas turbine engine 50, such as a part-load or full-load condition of the gas turbine engine 50. The sensors 126 may monitor the operating conditions of the gas turbine engine 50, such as a start-up condition, a steady-state condition, or a shut-down condition. The sensors 126 may monitor generator parameters (e.g., power output), the condition of the power grid, the output power from the turbine 62, etc.

[0023] The sensors 126 may include various sensor types to measure the aforementioned parameters. For example, the sensors 126 may include temperature sensors, such as thermocouples, thermistors, etc., located within the merger 12 and throughout the gas turbine system 10. The sensors 126 may also include flow sensors, such as flow meters (e.g., differential pressure flow meters, velocity flow meters, mass flow meters, positive displacement flow meters, open-drain flow meters), and liquid level sensors, such as continuous level transmitters, ultrasonic transducers, laser level transmitters, etc., located within the merger 12 and throughout the gas turbine system 10. Additionally, the sensors 126 may include pressure sensors, such as piezoresistive pressure sensors, differential pressure sensors, optical pressure sensors, etc., included within the merger 12 and throughout the gas turbine system 10. Fuel properties may be sensed and / or otherwise provided to the controller 124, for example, via human operator interfaces within the merger 12 and the gas turbine system 10. Fuel properties may include moisture content, carbon content, chemical composition, specific gravity, ambient temperature, energy content, specific "numbers" (e.g., Wobbe Index, cetane number, octane number, etc.), or combinations thereof. Emissions may include NO X Sensor, SO X The measured values may be measured by exhaust sensors such as CO2 sensors, CO sensors, and CO sensors.

[0024] The controller 124 is configured to receive and process measured inputs from the sensors 126 and control the operation of the gas turbine system 10, including the fluid flows 28, 36, and 40 through the merger 12. The controller 124 includes one or more processors 128, a memory 130, and instructions 132 stored in the memory 130 and executable by the processor 128 to control the operation of the gas turbine system 10. The processor 128 may include one or more “general-purpose” microprocessors, one or more special-purpose microprocessors, and / or one or more application-specific integrated circuits (ASICS), or some combination thereof. For example, the processor 128 may include one or more reduced instruction set (RISC) processors. The memory 130 may store information such as control software, lookup tables, configuration data, etc. Memory 130 may include a tangible, non-transitory, machine-readable medium, such as volatile memory (e.g., random access memory (RAM)) and / or non-volatile memory (e.g., read-only memory (ROM), flash memory, a hard drive, or any other suitable optical, magnetic, or solid-state storage medium, or a combination thereof). Memory 130 may store a variety of information that may be suitable for a variety of purposes. For example, memory device 130 may store machine-readable instructions and / or processor-executable instructions 132 (e.g., firmware or software) for processor execution.

[0025] The controller 124 may be communicatively coupled to an operator interface 134 (e.g., a human-machine interface (HMI)) and one or more actuators suitable for controlling components of the gas turbine system 10. For example, actuators (e.g., electric actuators) may be coupled to or integrated with each of the variable valve 26, the fan 38, the fan 94, the fuel supply for the combustor section 58, and other portions of the gas turbine engine 50. The controller 124 may also be coupled to valves, switches, positioners, pumps, etc. suitable for controlling various components of the gas turbine engine 50. The controller 124 may receive data from sensors 126, which may be used to control flow through the compressor 56, the combustor 60, the turbine 62, the load 52, and the combiner 12. As described in further detail below, the controller 124 is configured to control the fluid flows 28, 36, and 40 through the merger 12 based on various sensor feedback and operating modes (e.g., start-up mode, steady-state mode, shutdown mode, emergency mode, full load mode, part load mode, etc.) of the gas turbine system 10. In each of these modes, the controller 124 may adjust the variable valve 26 to adjust (e.g., increase or decrease) the compressor bleed flow 28, adjust one or both of the fans 38 and 94 to adjust (e.g., increase or decrease) the ventilation flow 36, or a combination thereof.

[0026] Figures 2, 3, and 4 are detailed views of one embodiment of the flow junction 12 of Figure 1. In particular, Figure 2 is a perspective view of one embodiment of the flow junction 12 of Figure 1. Figure 3 is a side view of one embodiment of the flow junction of Figure 2. Figure 4 is a front view of one embodiment of the flow junction of Figure 2. Further details of the flow junction 12 will now be described with reference to Figures 2-4.

[0027] As shown in FIGS. 2 and 3 , the illustrated inlet ducts 16 and 18 converge toward another outlet duct 14 in a Y-shaped configuration 138. For example, the inlet ducts 16 and 18 can converge at an angle 140, such as between 10 and 120 degrees, between 20 and 90 degrees, or between 30 and 60 degrees. The inlet duct 16 can change direction from the compressor bleed air intake conduit 112 toward the common duct portion 20 of the outlet duct 14. For example, the compressor bleed air intake conduit 112 can be substantially parallel to the outlet duct portion 14. The inlet duct 18 can change direction from a fan housing portion 142 (e.g., an upstream duct portion having an inlet 144) toward the common duct portion 20 of the outlet duct 14. For example, the fan housing portion 142 can be substantially perpendicular to the outlet duct portion 14. The flow confluence 12 may also include an intermediate duct portion 150 (e.g., a branching duct portion) between the compressor bleed intake conduit 112 and the common duct portion 20, and an intermediate duct portion 152 (e.g., a branching duct portion) between the fan housing portion 142 and the common duct portion 20. These intermediate duct portions 150 and 152 (e.g., branching duct portions) may define the convergence angle 140 of the inlet ducts 16 and 18.

[0028] A branch duct portion 150 of the first inlet duct 16 (e.g., a compressor bleed inlet duct) and a branch duct portion 152 of the second inlet duct 18 (e.g., a ventilation inlet duct) can help control the confluence of the fluid flows 28 and 36 into the common duct portion 20. In the illustrated embodiment, the branch duct portion 150 has diverging duct walls 154 and a cross-sectional flow area 156 that diverges or increases in the downstream direction of the fluid flow 28. Similarly, the branch duct portion 152 has diverging duct walls 158 and a cross-sectional flow area 160 that diverges or increases in the downstream direction of the fluid flow 36. However, in some embodiments, the cross-sectional flow areas 156 and 160 of the inlet ducts 16 and 18, respectively, may be wholly or partially constant, diverging, and / or converging in the downstream direction of the fluid flows 28 and 36. Additionally, the first minimum of the cross-sectional flow area 156 of the inlet duct 16 may be equal to, greater than, or less than the second minimum of the cross-sectional flow area 160 of the inlet duct 18 (e.g., if the fluid flow 28 is a higher energy flow than the fluid flow 36, the first minimum may be greater than the second minimum). Similarly, the first maximum of the cross-sectional flow area 156 of the inlet duct 16 may be equal to, greater than, or less than the second maximum of the cross-sectional flow area 160 of the inlet duct 18 (e.g., if the fluid flow 28 is a higher energy flow than the fluid flow 36, the first maximum may be greater than the second maximum). In some embodiments, the bifurcation of the duct walls 154 and / or the expansion of the cross-sectional flow area 156 may be the same as or different from the bifurcation of the duct walls 158 and / or the expansion of the cross-sectional flow area 160 (e.g., greater for higher energy flows).

[0029] As further shown in FIGS. 2 and 3 , the common duct portion 20 of the outlet duct 14 may have a cross-sectional flow area 162 that is larger than both the cross-sectional flow area 156 of the inlet duct 16 and the cross-sectional flow area 160 of the inlet duct 18. The common duct portion 20 may include a confluence section 22 having a plurality of flow mixers 24 (e.g., conduits, channels, baffles, etc. that serve to direct the flows to be mixed together). For example, the flow mixer 24 may include a backflow suppressor 32 having a plurality of conduits 34 that converge in the downstream direction of the fluid flows (e.g., 28, 36), thereby serving to suppress backflow while merging and mixing the fluid flows within the common duct portion 20. Details of the backflow suppressor 32 are described in further detail below with reference to FIG. 5 . The outlet duct 14 may also include a branching duct portion 164 that branches off in the downstream direction of the combined fluid flows 40. The silencer section 42 may be disposed in a uniform duct portion 166 having a constant cross-sectional flow area 168 downstream of the combined fluid streams 40. The outlet duct 14 may include a discharge section 170 having oppositely directed turning duct portions 172 and 174, which serve to disperse the combined streams 40 as they are discharged into the atmosphere. As shown in FIG. 4 , the turning duct portions 172 and 174 may include internal turning vanes or baffles 176 and 178, respectively. The baffles 176 and 178 are configured to split the combined fluid streams 40 and direct the split flows outward through the turning duct portions 172 and 174.

[0030] As described above, the flow combiner 12 may include various flow controls configured to control the ratio of the fluid stream 28 to the fluid stream 36, thereby helping to improve the merging of the fluid streams 28 and 36 without causing undesirable backflow and / or overloading the silencer section 42. In particular, the illustrated embodiment includes a variable valve 26 (e.g., a variable bleed valve (VBV)) configured to extend around the outer wall 114 of the compressor 56 shown in FIG. 1 and having a plurality of adjustable valve elements 30 (e.g., doors or flaps that open and close) circumferentially spaced around the compressor opening 116. The adjustable valve elements 30 may include actuators (e.g., electric actuators) coupled to a controller 124, such that the controller 124 can adjust the position of the adjustable valve elements 30 based on sensor feedback to help improve the merging within the flow combiner 12. The adjustable valve elements 30 may be configured to rotate and / or move axially between open and closed positions. The illustrated embodiment also includes multiple fans 38 within the inlet duct 18. The controller 124 is configured to selectively operate (i.e., turn on or off) and adjust the speed (e.g., increase or decrease the fan speed) of each of the fans 38, alone or in combination with one another, based on sensor feedback to help improve merging within the merger 12. The illustrated embodiment includes three fans 38 arranged in parallel within the inlet duct 18. However, embodiments of the merger 12 may have any number of fans 38 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10) arranged in series, parallel, or a combination thereof. By adjusting the variable valve 26 and / or the fans 38, the controller 124 can help enable successful merging of the fluid flows 28 and 36 within the merger 12 without causing backflow (e.g., backflow of the fluid flows 28 into the inlet duct 18) or overloading the merger 12. The inlet duct 18 also includes a damper 31 configured to open in response to a fluid flow 36 and to close in response to the fluid flow 36 ceasing.

[0031] Using the features described above, the flow combiner 12 combines or mixes two different types of flows, for example, a compressor bleed flow 28 (e.g., a variable bleed valve (VBV) flow) extracted or bled from the compressor 56 and a ventilation flow 36, 96 from the housing 54 surrounding the gas turbine engine 50. In one embodiment, the compressor bleed flow 28 may be a high-energy variable flow compared to the ventilation flow 36, which may be a continuous, low-energy flow. For example, the compressor bleed flow 28 may have a pressure range of 15 to 40 psi or any other suitable pressure range, depending on the extraction point on the compressor 56. In contrast, the ventilation flow 36 may have a pressure range of 10 to 15 psi or any other suitable pressure range to ventilate the housing 54. In another embodiment, the compressor bleed flow 28 may be a high-temperature flow compared to the ventilation flow 36, which may be a low- to medium-temperature flow. For example, the compressor bleed flow 28 may have a temperature range of 260°F to 300°F. In contrast, the ventilation flow 36 may have a temperature range of 120°F to 200°F. In a further embodiment, the compressor bleed flow 28 may operate as a separate flow for a specific time interval, which may range in duration from 1 to 10 seconds or any other suitable duration. Meanwhile, the ventilation flow 36 may operate as a continuous flow. Although the compressor bleed flow 28 and the ventilation flow 36 may have substantially different characteristics (e.g., noise level, continuous vs. intermittent, and energy level based on pressure, temperature, and flow rate), the combiner 12 can successfully combine the flows 28 and 36 using the variable valve 26, fan 38, damper 31, and backflow suppressor 32 while using a common silencer section 42. To improve handling of both the compressor bleed flow 28 and the ventilation flow 36 within the combiner 12, the controller 124 can control the flow rates of both flows 28 and 36 based on the particular operating mode of the gas turbine system 10. The various operating modes of the gas turbine system 10 are described in more detail below.

[0032] FIG. 5 is a perspective view of one embodiment of the backflow suppressor 32 of the flow confluencer 12 shown in FIGS. 1 and 3 , further illustrating one embodiment of the multiple conduits 34 of the backflow suppressor 32. As described above, the multiple conduits 34 are configured to facilitate confluence and mixing of the fluid flows 28 and 36 from the first inlet duct 16 and the second inlet duct 18 while suppressing backflow from one inlet duct to another (e.g., from the first inlet duct 16 to the second inlet duct 18 to the housing 54). As shown, each conduit 34 has a cross-sectional flow area 180 that constricts or decreases in the downstream flow direction. For example, each conduit 34 may have a tapered shape 182, e.g., duct walls 184 angled toward each other in the downstream flow direction of the fluid flows (e.g., 28 and 36). In some embodiments, each conduit 34 may include a conical conduit, a tapered square conduit, or a tapered polygonal conduit. The backflow suppressor 32 may include any number of multiple conduits 34 (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, or more). The conduits 34 may include two or more conduits of the same size and shape, two or more conduits of different sizes, two or more conduits of different shapes, or any combination thereof.

[0033] Each conduit 34 includes an inlet 186 and an outlet 188 having a downstream edge 190. Each conduit 34 has a first dimension 192 at the inlet 186 and a second dimension 194 at the outlet 188. Dimensions 192 and 194 may comprise the width, diameter, or cross-sectional flow area of the conduit 34. Dimension 194 of the outlet 188 is smaller than dimension 192 of the inlet 186 by a certain percentage or factor to help prevent backflow. For example, dimension 194 may be no greater than about 10, 20, 30, 40, 50, 60, 70, or 80% of dimension 192. In some embodiments, dimension 192 may correspond to the maximum dimension of the conduit 34, and dimension 194 may correspond to the minimum dimension of the conduit 34. The outlet 188 may also define a throat or flow-restricting orifice that regulates fluid flow (e.g., 28 and 36) and prevents backflow. Additionally, the dimensions 192 and 194 may be selected to restrict or regulate the fluid flow (e.g., 28 and 36) from the inlet ducts 16 and 18 to the outlet duct 14 of the merger 12 while also inhibiting backflow of the fluid flow (e.g., compressor bleed flow 28 into the inlet duct 18). For example, the dimensions 192 and 194 may be increased to increase the fluid flow (e.g., 28 and 36), or the dimensions 192 and 194 may be decreased to decrease the fluid flow (e.g., 28 and 36). The conduit 34 may also vary in size, shape, amount, and convergence rate (or convergence angle) from the inlet 186 to the outlet 188 to help regulate the fluid flow (e.g., 28 and 36) and inhibit backflow. The downstream edge 190 of the outlet 188 may be a smooth edge or a variable edge (e.g., a jagged or toothed edge having multiple teeth 196). The variable edge with teeth 196 may be configured to help spread the fluid streams (eg, 28 and 36) within the junction 12 while adding additional surface area to inhibit backflow.

[0034] 6 is a schematic cross-sectional side view of the merger 12 coupled to the compressor 56 of the gas turbine system 10 of FIG. 1 , illustrating a compressor bleed intake conduit 112 having a variable valve 26 (e.g., a variable bleed valve (VBV)) configured to regulate the compressor bleed air flow 28 into the merger 12. The compressor bleed intake conduit 112 may be an integral part (i.e., one piece) of the inlet duct 16 of the merger 12, or the compressor bleed intake conduit 112 may be a separate component removably or fixedly coupled to the inlet duct 16. The compressor 56 is disposed inside the compressor bleed intake conduit 112 along with a compressor opening 116. As shown, the compressor opening 116 is annular and thus fits around an outer wall 114 (e.g., an annular wall) of the compressor 56. However, the compressor opening 116 and outer wall 114 may have other shapes at the connection between the compressor bleed intake conduit 112 and the compressor 56 .

[0035] The compressor bleed intake conduit 112 includes a variable valve 26 having a plurality of adjustable valve elements 30 (e.g., doors or flaps) arranged circumferentially around the compressor opening 116. The adjustable valve elements 30 serve to adjust the compressor bleed flow 28 within the inlet duct 16 and, therefore, within the flow junction 12. In some embodiments, the adjustable valve elements 30 may be a collection of circumferentially spaced valves, doors, or flaps configured to rotate or move axially between open and closed positions. The adjustable valve elements 30 may vary in size, shape, and quantity. There may be uniform or non-uniform circumferential gaps between the adjustable valve elements 30. For example, each of the adjustable valve elements 30 may be separated from one another by a circumferential gap having a fixed spacing size, such as 6 inches, 1 foot, or any other suitable distance. The opening and closing of the adjustable valve elements 30 may be adjusted via the driver 200 to adjust the compressor bleed flow 28 in the inlet duct 16 and in the flow junction 12. The adjustable valve elements 30 may open and close simultaneously or cyclically to adjust the compressor bleed flow 28.

[0036] In some embodiments, the driver 200 may include an electric driver, a fluid driver (e.g., a hydraulic driver and / or a pneumatic driver), or a combination thereof. The driver 200 may be coupled to an energy source 202 and one or more actuators 204 coupled to the adjustable valve element 30. For example, the energy source 202 may include an electrical power supply and / or a fluid supply (e.g., a pressurized fluid tank, a compressor, or a pump). The driver 200 is configured to move the actuator 204, which in turn moves the adjustable valve element 30 between the open and closed positions. Thus, the actuator 204 may include a mechanical linkage, a rotary joint, a piston-cylinder assembly, or a transmission assembly configured to transmit force from the driver 200 to the adjustable valve element 30. In fluid-driven embodiments, the driver 200 (e.g., a fluid driver) uses pressurized fluid (e.g., liquid or gas) from the energy source 202 (e.g., a fluid supply) to provide force to adjust the opening and closing of the adjustable valve element 30. For example, the drive 200 (e.g., a fluid drive) may include a piston-cylinder assembly driven by pressurized fluid from an energy source 202. Further, the drive 200 may be controlled by the controller 124 to adjust the position of the adjustable valve element 30 and thus vary the flow of the compressor bleed flow 28 through the flow combiner 12.

[0037] As previously described, to improve combining of the fluid stream 28 (e.g., compressor bleed flow) and the fluid stream 36 (e.g., ventilation flow), the flow rates associated with each fluid stream may be controlled based on the operating mode of the gas turbine system 10. FIG. 7 is a flowchart of an embodiment of a method 350 for operating the gas turbine system 10 in different modes using the flow combiner 12 of FIGS. 1-6. The operating modes are not limited to the modes described herein but rather may serve as examples. The flow rates associated with the compressor bleed flow 28 and the ventilation flow 36 may be continuously or periodically monitored by the controller 124 via a control algorithm. In the illustrated embodiment, the method 350 includes monitoring the operation of the gas turbine system 10, as indicated by block 360, and changing the operating mode of the gas turbine system 10 based on the monitored conditions, as indicated by block 362. The method 350 may then query the operating mode, as indicated by block 364, and proceed with the change depending on the operating mode.

[0038] For example, if query block 364 indicates start mode 366, the method 350 may control the variable valve 26 to adjust the compressor bleed flow 28 (e.g., variable bleed valve (VBV) flow) to be relatively low and / or increased when the gas turbine engine 50 is accelerating, as indicated by block 374. Further, in start mode 366, the method 350 may control the fan 38 and / or 94 to adjust the ventilation flow 36, 96 to be at full flow (e.g., vent flow full), as indicated by block 382. During start mode 366, the compressor bleed flow 28 may be increasing but may still be operating at a low flow rate, while the ventilation flow 36 may be operating at full flow rate. During start mode 366, the compressor blades are increasing their rotational speed to reach a threshold speed of the gas turbine engine 50. As a result, the compressor bleed flow 28 may be operating at a low flow rate when the gas turbine engine 50 is starting or beginning to rotate. However, as the compressor blades increase rotational speed and the gas turbine engine 50 progresses toward full load operation, the compressor bleed flow 28 increases but may still operate at a lower flow rate compared to maximum flow rate, while the ventilation flow 36 may be operating at full flow rate.

[0039] If query block 364 indicates a full load mode 368, the method 350 may control the variable valve 26 to regulate the compressor bleed flow 28 (e.g., VBV flow) to fully close (or nearly close) when the gas turbine engine 50 is operating at full load, as indicated by block 376. Further, in the full load mode 368, the method 350 may control the fan 38 and / or 94 to regulate the ventilation flow 36, 96 to full flow (e.g., vent flow full), as indicated by block 384. During the full load mode 368, the compressor bleed flow 28 may be closed, and the ventilation flow 36 may be operating at full flow. When the gas turbine engine 50 is operating in full load mode, the gas turbine engine 50 may be releasing a maximum amount of heat. As a result, the ventilation flow 36 operating at full flow may be useful for cooling the gas turbine engine 50 and the space within the enclosure 54.

[0040] If query block 364 indicates a normal shutdown mode 370, the method 350 may control the variable valve 26 to regulate the compressor bleed flow 28 (e.g., VBV flow) to open at a moderate flow when the gas turbine engine 50 is shut down in a normal manner, as indicated by block 378. The moderate flow of the compressor bleed flow 28 may be an intermediate level between no flow and maximum flow. Further, in the normal shutdown mode 370, the method 350 may control the fans 38 and / or 94 to regulate the ventilation flow 36, 96 to full flow (e.g., full vent flow), as indicated by block 386. During the normal shutdown mode 370, the gas turbine engine 50 may be slowing down gradually (rather than an emergency or rapid slowdown) due to some unexpected event or emergency. As a result, the variable valve 26 may be opened such that the compressor bleed flow 28 is operating at a moderate flow, and the ventilation flow 36 may be operating at full flow.

[0041] If query block 364 indicates an emergency shutdown and / or load reduction mode 372, the method 350 may control the variable valve 26 to regulate the compressor bleed flow 28 (e.g., VBV flow) to open at maximum flow rate when the gas turbine engine 50 is rapidly shut down in an emergency manner and / or unexpectedly reducing load, as indicated by block 380. Further, in mode 372, the method 350 may control the fans 38 and / or 94 to regulate the ventilation flow 36, 96 to be reduced or at partial flow (e.g., vent flow reduced from full flow), as indicated by block 388. During the emergency shutdown and / or load reduction mode 372, the compressor bleed flow 28 may be operating at maximum flow rate and the ventilation flow 36 may be operating at a reduced flow rate. The compressor bleed flow 28 may be operating at full capacity to reduce the likelihood of the gas turbine engine 50 surging or stalling. The compressor bleed flow 28 may be operating at full capacity for a short period of time, such as 5 seconds, 10 seconds, or any other suitable period of time. Because the compressor bleed flow 28 may be operating at full flow rate for a reduced amount of time, the flow rate of the ventilation flow 36 may also be reduced.

[0042] 1-6 is configured to combine fluid flows 28 and 36 with the aforementioned control provided by method 350 of FIG. 7 , thereby reducing the possibility of backflow and helping to avoid overloading silencer section 42 and other portions of combiner 12. While the illustrated method 350 has several specific operating modes and corresponding adjustments to fluid flows 28 and 36, other operating modes and adjustments to fluid flows 28 and 36 may be used to help combine the flows through combiner 12.

[0043] The technical effect of the present invention includes a combiner 12 for combining the compressor bleed flow 28 and the ventilation flow 36. In particular, the combiner 12 may include a shared or common silencer section 42 to attenuate noise from the combined flow 40 (i.e., the combination of the compressor bleed flow 28 and the ventilation flow 36). To effectively combine the flows, the controller 124 may continuously or periodically adjust the flow rates associated with the compressor bleed flow 28 and the ventilation flow 36 based on various operating modes of the gas turbine system 10. The combiner 12, which facilitates the mixing of the compressor bleed flow 28 and the ventilation flow 36, includes two distinct inlet ducts 16 and 18. The inlet duct 16 may be designated as an inlet for the bleed flow 28 to enter the combiner 12, and the inlet duct 18 may be designated as an inlet for the ventilation flow 36 to enter the combiner 12. After both the ventilation flow 36 and the compressor bleed flow 28 enter the combiner 12 via their respective inlet ducts 16 and 18 (e.g., through backflow suppressors 32), the flows may mix within the combiner 12. In particular, the inlet duct 16 may include an adjustable valve element 30 that adjusts the volume of the compressor bleed flow 28 via a drive 200 and an actuator 204. Meanwhile, the inlet duct 18 may include one or more fans 38 and dampers 31 to adjust the ventilation flow 36 and suppress backflow of the compressor bleed flow 28 through the inlet duct 18.

[0044] This specification 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 device or system 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 within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they contain equivalent structural elements that are not substantially different from the literal language of the claims. [Explanation of symbols]

[0045] 10 Gas Turbine System 12 Combiner 14 Exit duct 16 First inlet duct 18 Second inlet duct 20 Common duct section 22 Merging Section 24 Flow Mixer 26 Variable valve, variable bleed valve 28 Compressor bleed flow, fluid flow 30 Adjustable Valve Elements 31 Damper 32 Backflow suppressor 34 Conduit 36 Ventilation flow, fluid flow 38 fans 40 Combined fluid flow 42 silencer section 44 silencer baffle 50 Gas Turbine Engine 52 Load, generator 54 Case 56 Compressor 58 Combustor Section 60 Combustor 62 Turbine 64 Combustion Nozzle 66 Compressed Air 68 Combustion chamber 70 Hot combustion gases 72 Shaft 74 Exhaust Gas 76 Exhaust Section 80 Intake 82 Intake system 84 Filter Section 86 Air filter 88 Air inlet duct 90 Air inlet duct 92 Opening 94 fans 96 Ventilation Airflow 102 Compressor inlet 104 Compressor intake flow 110 Compressor bleed section 112 Compressor bleed intake duct 114 Exterior Wall 116 Compressor opening 120 Control System 122 Surveillance System 124 Controller 126 Sensors 128 processors 130 Memory, memory devices 132 Command 134 Operator Interface 138 Y-shaped structure 140 convergence angle 142 Fan housing part 144 Entrance 150 Branch duct section, intermediate duct section 152 Branch duct section, intermediate duct section 154 Duct Wall 156 Cross-sectional flow area 158 Duct Wall 160 Cross-sectional flow area 162 Cross-sectional flow area 164 Branch duct section 166 Uniform duct section 168 Cross-sectional flow area 170 Discharge Section 172 Turning duct part 174 Turning duct part 176 Internal turning vanes or baffles 178 Internal turning vanes or baffles 180 Cross-sectional flow area 182 Tapered shape 184 Duct Wall 186 Entrance 188 Exit 190 downstream edge 192 First Dimension 194 Second Dimension 196 teeth 200 Drive Unit 202 Energy Sources 204 Actuator 350 methods 364 query blocks 366 Starting Mode 368 Full Load Mode 370 Normal stop mode 372 Emergency Stop and / or Load Reduction Mode

Claims

1. an outlet duct (14); a compressor bleed inlet duct (16) coupled to the outlet duct (14), the compressor bleed inlet duct (16) configured to receive a bleed air flow (28) from a compressor (56) of a gas turbine engine (50); a ventilation inlet duct (18) coupled to the outlet duct (14), the ventilation inlet duct (18) configured to receive a ventilation flow (36) from a housing (54) surrounding the gas turbine engine (50); A junction (12) comprising: Equipped with the bleed flow (28) and the ventilation flow (36) join as an outlet flow through the outlet duct (14); system.

2. 2. The system of claim 1, wherein the compressor bleed inlet duct comprises a compressor opening configured to extend circumferentially around an outer wall of the compressor, and the compressor bleed inlet duct comprises a variable bleed valve.

3. The system of claim 1, wherein the compressor bleed inlet duct (16) and the ventilation inlet duct (18) join to a common duct portion (20) of the outlet duct (14).

4. The system of claim 3, wherein the outlet duct (14) comprises turning duct portions (172, 174).

5. The system of claim 3, wherein the common duct portion (20) comprises a backflow suppressor (32) having a plurality of conduits (34) of varying cross-sectional flow areas.

6. 2. The system of claim 1, wherein the ventilation inlet duct comprises a damper configured to open in response to the ventilation flow, and the compressor bleed inlet duct comprises a plurality of adjustable valve elements for adjusting the bleed flow within the flow combiner.

7. The system of claim 1 , wherein the outlet duct (14) comprises one or more silencer baffles (44).

8. receiving a bleed air flow (28) from a compressor (56) of a gas turbine engine (50) into a compressor bleed air inlet duct (16) coupled to an outlet duct (14) of a flow combiner (12); receiving a ventilation flow (36) from a housing (54) surrounding the gas turbine engine (50) into a ventilation inlet duct (18) coupled to the outlet duct (14), the bleed flow (28) and the ventilation flow (36) joining as an outlet flow through the outlet duct (14); A method comprising:

9. 9. The method of claim 8, comprising adjusting, via a controller, the bleed flow or the ventilation flow based on one or more operating parameters of the gas turbine engine.

10. 10. The method of claim 9, wherein the one or more operating parameters include an operating mode of the gas turbine engine, the operating mode of the gas turbine engine comprising one of a start mode, a full load mode, a normal shutdown mode, or an emergency shutdown / load reduction mode.

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