Embodiments of a combustion section including a fuel injector assembly are provided. The combustion section includes the fuel injector assembly coupled to an outer casing and a liner assembly. The fuel injector assembly includes a body defining a first inlet opening and a second inlet opening spaced apart from one another along a first direction. The body further defines a fuel-oxidizer mixing passage therewithin extended along a second direction at least partially orthogonal to the first direction. The first inlet opening and the second inlet opening are each in fluid communication with the fuel-oxidizer mixing passage. The body defines an outlet opening at the fuel-oxidizer mixing passage at a distal end relative to the first inlet opening and the second inlet opening. The first inlet opening and the second inlet opening are each configured to admit a flow of oxidizer to the fuel-oxidizer mixing passage. The fuel-oxidizer mixing passage is configured to provide a flow of fuel-oxidizer mixture to a combustion chamber via the outlet opening.

A method for operating a gas turbine engine comprises providing fuel flow and compressed airflow to a combustor with a fuel-to-air ratio, the compressed airflow being from a compressed air source; detecting at least one parameter indicative of the fuel-to-air ratio being below a predetermined value; and bleeding compressed air from the compressed air source when the at least one parameter indicative of the fuel-to-air ratio is below the predetermined value to increase the fuel-to-air ratio to at least the predetermined value.

Turbomachines and methods of operating turbomachines are provided. The turbomachine may include a compressor, a turbine, and a plurality of combustors downstream from the compressor and upstream from the turbine. The turbomachine may also include a plurality of igniters. Methods of operating a turbomachine may include rotating a shaft of the turbomachine at a first speed and rotating the shaft of the turbomachine at a second speed different from the first speed after rotating the shaft of the turbomachine at the first speed. The methods may also include firing at least one igniter of the plurality of igniters repeatedly throughout the period of time at a regular interval and/or when the rotational speed reaches at least one predetermined speed threshold during the period of time.

Methods and systems for resonance suppression, can involve measuring signals with one or more sensors, wherein the signals are produced by a combustor associated with an actuator, and receiving at a controller the signals measured by the sensor or sensors. The controller can calculate a damping rate of the combustor. Based on the damping rate, the controller can modulate the actuator if the damping rate falls below a predefined threshold and can continue to modulate the actuator until the damping rate is adjusted and the resonance is suppressed. The sensor can be an acoustic sensor, an optical sensor, or another type of sensor.

The present disclosure provides a tuning system for tuning the operation of a gas turbine. The system comprises operational turbine controls for controlling operational control elements of the turbine, including at least one of turbine fuel distribution or the fuel temperature. The system also has a tuning controller communicating with the turbine controls. The tuning controller is configured to tune the operation of the turbine in accordance with the following steps: receiving operational data about the turbine, providing a hierarchy of tuning issues, determining whether sensed operational data is within predetermined operational limits and producing one or more indicators. If the operational data is not within predetermined operational limits, the tuning controller will rank the one or more indicators to determine dominant tuning concern, and tune the operation of the turbine based on dominant tuning concern. Also provided herein are a method and computer readable medium for tuning.

A method for predicting an anomaly in a combustor (16) is presented. The method includes receiving signals representative of parameters in one or more combustion cans (22, 24) of the combustor, generating a plurality of patterns based on a permutation entropy window and the signals, identifying a plurality of pattern categories in the plurality of patterns, determining a permutation entropy based on the plurality of patterns and the plurality of pattern categories, and predicting an anomaly in the combustor based on the permutation entropy. The method further includes comparing the plurality of pattern categories to determined permutations of pattern categories if the anomaly is present in the combustor, and predicting a category of the anomaly based on the comparison of the plurality of pattern categories to the determined permutations of pattern categories.

[Object] To observe the sign or occurrence of an unstable operation of a turbo-machine. [Solving Means] An observation apparatus 1 includes: a detection unit 10 including one or two or more sensors 11, 12 that are disposed in a turbo-machine 2, are highly time responsive, and observe unsteady fluctuations of the turbo-machine 2; a computation unit 20 that output signals from the one or two or more sensors 11, 12 every moment, stores time series data for a predetermined period, and calculates in real time a parameter for detecting an unstable operation of the turbo-machine; and a determination unit 30 that compares the parameter for detecting the unstable operation with a predetermined threshold and outputs in real time a determination result of a sign or occurrence of the unstable operation.

A pulse combustor system for reducing noise and/or vibration levels. The system includes a pulse combustor including a combustion chamber, an inlet pipe, an exhaust pipe, and a first fuel injector for injecting fuel into the combustion chamber. The pulse combustor has a fundamental oscillation mode and one or more additional oscillation modes. The system includes at least one pressure sensor for measuring a pressure inside the fuel combustor and/or a at least one fluid velocity sensor for measuring fluid velocity at the inlet pipe or at the exhaust pipe. A controller adjusts a rate of fuel supply to the pulse combustor if the measured pressure and/or the measured velocity is above a predetermined threshold value to reduce excitation of the one or more additional oscillation modes.

A system for early detection of onset of oscillatory instabilities in practical devices is described. The system consists of a measuring device (102), an instability detection unit (104) and a control unit (106). The measuring device (102) is configured to generate signals corresponding to the dynamics happening inside the practical device. The instability detection unit (104) along with an amplitude estimation unit (130) is configured to diagnose the stability of the practical device from the signals that are generated by the measuring device (102). Further, the control unit (106) is configured to control various operating parameters in the practical device based on the information obtained from the instability detection unit (104).

Various kinds of oscillatory instabilities are seen in practical systems. We devise of way of combating these oscillatory instabilities in a thermoacoustic system. Confined combustion environments are prone to large amplitude pressure oscillations known as thermoacoustic instabilities. Although several techniques have been employed to control or mitigate such instabilities, optimization of these methods is achieved at the cost of performing multiple trial and error experiments/simulations. This invention develops a methodology to quantify the spatio-temporal dynamics using synchronization, recurrence, and fractal measures and find the coherent region in such turbulent flow field. Such an analysis provides us with a novel way to detect critical regions responsible for thermoacoustic instability, and other oscillatory instabilities in general, in the flow field and implement an optimized control strategy at these regions.