Abstract: A combustor (28) for a gas turbine engine is provided comprising a primary combustion chamber (30) for combusting a first fuel to form a combustion flow stream (50) and a transition piece (32) located downstream from the primary combustion chamber (30). The transition piece (32) comprises a plurality of injectors (66) located around a circumference of the transition piece (32) for injecting a second fuel into the combustion flow stream (50). The injectors (66) are effective to create a radial temperature profile (74) at an exit (58) of the transition piece (32) having a reduced coefficient of variation relative to a radial temperature profile (64) at an inlet (54) of the transition piece (32). Methods for controlling the temperature profile of a secondary injection are also provided.

Abstract: A method of transitioning from a first operating mode to a second operating in a gas turbine engine. An amount of fuel provided to a primary fuel injection system of the combustor apparatus is reduced. An amount of fuel provided to a secondary fuel/air injection system of the combustor apparatus is reduced, wherein the secondary fuel/air injection system provides fuel to a secondary combustion zone downstream from a main combustion zone. A total amount of air provided to the combustor apparatus is reduced, wherein portions of the air are provided to each of the injection systems. Upon reaching operating parameters corresponding to the second operating mode, the amount of fuel provided to the primary fuel injection system is increased, the amount of fuel provided to the secondary fuel/air injection system is reduced, and the total amount of air provided to the combustor apparatus is increased.

Abstract: A thermal shield for reducing thermal stress induced proximate to a first joint formed between adjacent engine casing components in a gas turbine engine. The thermal shield includes a cover structure for covering a radially inner portion of at least one of the engine casing components. The cover structure is disposed proximate to the first joint and attached to the respective engine casing component so as to limit exposure of a covered inner portion of the engine casing component to hot gases in an interior volume defined by the engine casing components. A thermally insulating layer is disposed between the cover structure and the engine casing component for effecting a reduced amount of heat transfer to the covered inner portion of the engine casing component from the hot gases in the interior volume defined by the engine casing components.

Abstract: A gas turbine combustion system is provided comprising a combustion chamber (16) having a central axis (44), a primary combustion stage (28) located at a front end (32) of the combustion chamber (16) for injecting fuel, air, or mixtures thereof substantially along the central axis (44), a plurality of secondary combustion stages (30A-D) spaced apart in flow series along a length of the combustion chamber (16), wherein each of the plurality of secondary combustion stages (30A-D) comprises a plurality of circumferentially-spaced secondary injectors (48) for injecting fuel, air, or mixtures thereof, toward the central axis (44), and wherein an internal diameter of the combustion chamber (16) decreases from at least a first one of the plurality of secondary combustion stages (30AD) to at least a second one of the plurality of secondary combustion stages (30A-D).

Abstract: A fuel injector (36) for alternate fuels (26A, 26B) with energy densities that differ by at least about a factor of two. Vanes (47B) extend radially from a fuel delivery tube structure (20B) with first and second fuel supply channels (19A, 19B). Each vane has first and second radial passages (21A, 21B) communicating with the respective fuel supply channels, and first and second sets of apertures (23A, 23B) between the respective radial passages and the surface (49) of the vane. The first fuel supply channel, first radial passage, and first apertures form a first fuel delivery pathway providing a first fuel flow rate at a given backpressure. The second fuel supply channel, second radial passage, and second apertures form a second fuel delivery pathway providing a second fuel flow rate that may be at least about twice first fuel flow rate at the given backpressure.

Abstract: A thermal shield for reducing thermal stress induced proximate to a first joint formed between adjacent engine casing components in a gas turbine engine. The thermal shield includes a cover structure for covering a radially inner portion of at least one of the engine casing components. The cover structure is disposed proximate to the first joint and attached to the respective engine casing component so as to limit exposure of a covered inner portion of the engine casing component to hot gases in an interior volume defined by the engine casing components. A thermally insulating layer is disposed between the cover structure and the engine casing component for effecting a reduced amount of heat transfer to the covered inner portion of the engine casing component from the hot gases in the interior volume defined by the engine casing components.

Abstract: A secondary fuel delivery system for delivering a secondary stream of fuel and/or diluent to a secondary combustion zone located in the transition piece of a combustion engine, downstream of the engine primary combustion region is disclosed. The system includes a manifold formed integral to, and surrounding a portion of, the transition piece, a manifold inlet port, and a collection of injection nozzles. A flowsleeve augments fuel/diluent flow velocity and improves the system cooling effectiveness. Passive cooling elements, including effusion cooling holes located within the transition boundary and thermal-stress-dissipating gaps that resist thermal stress accumulation, provide supplemental heat dissipation in key areas.

Abstract: In one embodiment, a combustor (28) for a gas turbine engine is provided comprising a primary combustion chamber (30) for combusting a first fuel to form a combustion flow stream (50) and a transition piece (32) located downstream from the primary combustion chamber (30). The transition piece (32) comprises a plurality of injectors (66) located around a circumference of the transition piece (32) for injecting a second fuel into the combustion flow stream (50). The injectors (66) are effective to create a radial temperature profile (74) at an exit (58) of the transition piece (32) having a reduced coefficient of variation relative to a radial temperature profile (64) at an inlet (54) of the transition piece (32). Methods for controlling the temperature profile of a secondary injection are also provided.

Abstract: A gas turbine combustion system is provided comprising a combustion chamber (16) having a central axis (44), a primary combustion stage (28) located at a front end (32) of the combustion chamber (16) for injecting fuel, air, or mixtures thereof substantially along the central axis (44), a plurality of secondary combustion stages (30A-D) spaced apart in flow series along a length of the combustion chamber (16), wherein each of the plurality of secondary combustion stages (30A-D) comprises a plurality of circumferentially-spaced secondary injectors (48) for injecting fuel, air, or mixtures thereof, toward the central axis (44), and wherein an internal diameter of the combustion chamber (16) decreases from at least a first one of the plurality of secondary combustion stages (30A-D) to at least a second one of the plurality of secondary combustion stages (30A-D).

Abstract: A secondary fuel delivery system for delivering a secondary stream of fuel and/or diluent to a secondary combustion zone located in the transition piece of a combustion engine, downstream of the engine primary combustion region is disclosed. The system includes a manifold formed integral to, and surrounding a portion of, the transition piece, a manifold inlet port, and a collection of injection nozzles. A flowsleeve augments fuel/diluent flow velocity and improves the system cooling effectiveness. Passive cooling elements, including effusion cooling holes located within the transition boundary and thermal-stress-dissipating gaps that resist thermal stress accumulation, provide supplemental heat dissipation in key areas.

Abstract: An embodiment of the invention provides an apparatus and a method for an adaptive arena assignment based on arena contentions. The apparatus and method include: receiving a request for memory from a software thread; determining a lock hit counter with a lowest value; and assigning the software thread to an arena associated with lock hit counter.

Abstract: A method of handling a signal for delivery to a process in a process group along with an apparatus and computer-readable medium storing instructions therefore are described. The method comprises obtaining a lock on a portion of a process group management structure and storing a signal to the process group management structure, wherein the signal is to be delivered to one or more processes of a process group, wherein an operating system manages the process group management structure. The method further comprises transmitting a wakeup signal to a signal daemon and releasing the obtained lock. A method of delivering a signal to a process in a process group is also described. The method comprises obtaining a signal from a process group management structure, obtaining a lock on a process list, transmitting the signal to a process specified in the process list; and releasing the lock on the process list.

Abstract: An extended flashback annulus (520) is formed between an exterior surface (506) of a shroud or casing (508) associated with a main swirler assembly inner body (500) or other fuel/air mixing device and the inner surface (514) of an annulus casting (510) which are in operational relationship with one another in a gas turbine combustor assembly. The extended flashback annulus (520) is capable of forming an extended protective cylindrical air barrier (550) that extends farther into the combustion zone, this barrier being more robust and providing for the reduction or prevention of flashback to the baseplate and other heat-susceptible upstream components.

Abstract: An extended flashback annulus (520) is formed between an exterior surface (506) of a shroud or casing (508) associated with a main swirler assembly inner body (500) or other fuel/air mixing device and the inner surface (514) of an annulus casting (510) which are in operational relationship with one another in a gas turbine combustor assembly. The extended flashback annulus (520) is capable of forming an extended protective cylindrical air barrier (550) that extends farther into the combustion zone, this barrier being more robust and providing for the reduction or prevention of flashback to the baseplate and other heat-susceptible upstream components.

Abstract: One embodiment disclosed relates to a method of obtaining status information from user threads of a target process. A system call is performed from a querying process. The system call creates a kernel debug thread in a kernel entity of the target process. The kernel debug thread further creates a user status thread in a user entity of the target process. The method may be used to obtain the status information without stopping the target process. Another embodiment disclosed relates to an operating system with capability to obtain status information from user threads of a target process. The operating system includes at least the following first and second system calls. The first system call is configured to create a kernel debug thread in a kernel entity of the target process. The second system call is configured to awake the kernel debug thread and pass information to the kernel debug thread.

Abstract: A system and computer-implemented method of converting a contention scope attribute of a user thread executing in a multithreaded environment are described. The method includes dynamically converting the contention scope attribute of the user thread running in the multithreaded environment between a process scope and a system scope. In changing from system scope to process scope, the kernel thread to which the user thread is mapped is converted to a scheduler activation thread, the contention attribute for the user thread is reset in a threads library and the user thread is added to the run queue of a relevant virtual processor. In changing from process scope to system scope, the underlying scheduler activation kernel thread is permanently and exclusively mapped to the user thread to achieve a system scope for the thread. And a replacement scheduler activation kernel thread is created for other user threads of the same process previously sharing the original scheduler activation kernel thread.

Abstract: Aspects of the invention relate to an improved acoustic termination for a pressure monitoring system. The termination can include an inner tube having a passage extending therethrough. One end of the inner tube can extend into an open end of an outer tube, which is closed at its opposite end. The portion of the inner tube that extends into the outer tube can include a plurality of apertures. Sound absorption material can fill the space between the outer tube and the portion of the inner tube extending therein. A pressure signal entering the acoustic termination can be substantially dissipated and can minimize signal reflection from the termination. As a result a more accurate pressure measurement can be obtained by a pressure measurement device that operatively connects to the passage upstream of the termination.

Abstract: One embodiment disclosed relates to a method of obtaining status information from user threads of a target process. A system call is performed from a querying process. The system call creates a kernel debug thread in a kernel entity of the target process. The kernel debug thread further creates a user status thread in a user entity of the target process. The method may be used to obtain the status information without stopping the target process. Another embodiment disclosed relates to an operating system with capability to obtain status information from user threads of a target process. The operating system includes at least the following first and second system calls. The first system call is configured to create a kernel debug thread in a kernel entity of the target process. The second system call is configured to awake the kernel debug thread and pass information to the kernel debug thread.