A tunable diode laser absorption spectroscopy (TDLAS) optical head includes a housing configured for attachment to a sight tube attached to a wall of a process chamber. The TDLAS optical head further includes optics within the housing for transmitting, receiving, or transmitting and receiving a laser beam within a process chamber through the sight tube. The TDLAS optical head further includes a photo sensor in the housing positioned to receive light emitted by combustion within the process chamber to which the housing is attached.

A flame sensor apparatus includes a sensor assembly. The sensor assembly includes a photodiode for sensing characteristics of a flame. The photodiode outputs an electrical photocurrent. The sensor assembly includes an electrical assembly that is electrically remote from the sensor assembly. The sensor assembly includes an electric cable assembly extending from the sensor assembly to the electrical assembly. The electric cable assembly includes an electrical cable to electrically convey the photocurrent to the electrical assembly. At least the sensor assembly is configured and constructed to experience and continue to operate at a temperature at or greater than 200 C.

A method of monitoring blockage of a sight tube attached to a wall of a process chamber, the sight tube being operatively associated with a TDLAS optical head with a window between the sight tube and the TDLAS optical head. The method includes the steps of providing a photo sensor in the TDLAS optical head, the photo sensor being positioned to receive light emitted by a light emitting process within the process chamber. An emission signal produced by light emitted by the light emitting process within the process chamber being received by the photo sensor is monitored. A determination is made if the emission signal is degrading.

A method of monitoring blockage of a sight tube attached to a wall of a process chamber, the sight tube being operatively associated with a TDLAS optical head with a window between the sight tube and the TDLAS optical head. The method includes the steps of providing a photo sensor in the TDLAS optical head, the photo sensor being positioned to receive light emitted by a light emitting process within the process chamber. An emission signal produced by light emitted by the light emitting process within the process chamber being received by the photo sensor is monitored. A determination is made if the emission signal is degrading.

The invention includes a method for predicting the operational state of equipment with turbulent flow characterized by time series data relating to its operation. The invention further includes a system and method for predicting the onset of an impending oscillatory instability. Further, the invention includes a system and method for identifying an impending absorbing transition such as flame blowout in combustion systems. A variable representing the dynamics of operation is measured with the help of a sensor, to obtain time series data. A complex network is then derived from the measured time series data. Network properties are then calculated using the complex network to identify the state of stability relating to operation of the equipment. The stability information may include one of thermoacoustic instability, aero-elastic instability such as flutter, flow-induced vibration, magneto-hydrodynamic, aerodynamic, aeromechanical, aero-acoustic instability or onset of flame blowout of a combustor.

The invention includes a method for predicting the operational state of equipment with turbulent flow characterized by time series data relating to its operation. The invention further includes a system and method for predicting the onset of an impending oscillatory instability. Further, the invention includes a system and method for identifying an impending absorbing transition such as flame blowout in combustion systems. A variable representing the dynamics of operation is measured with the help of a sensor, to obtain time series data. A complex network is then derived from the measured time series data. Network properties are then calculated using the complex network to identify the state of stability relating to operation of the equipment. The stability information may include one of thermoacoustic instability, aero-elastic instability such as flutter, flow-induced vibration, magneto-hydrodynamic, aerodynamic, aeromechanical, aero-acoustic instability or onset of flame blowout of a combustor.

A fresh-air intake according to aspects of the disclosure includes an outer cover having a pair of side panels disposed in a generally parallel spaced relationship, a top panel coupled to, and disposed generally perpendicular to, each panel of the pair of side panels, a bottom panel disposed generally parallel to the top panel, and a front panel coupled to, and disposed generally perpendicular to, each panel of the pair of side panels and the top panel, the front panel having a window formed therein, a supply line coupled to the bottom panel, a weir extending above the bottom panel and surrounding a junction with the supply line, a baffle disposed inside the outer cover, the baffle being disposed inwardly of the window so as to prevent infiltration of moisture into the supply line, and a weep hole formed in the bottom panel.

Aspects of the disclosure are directed to a case for a gas turbine engine, the case including a case wall and a boss that extends from the case wall, the boss including a distal top contoured surface with a through hole fotmed there in, the distal top contoured surface having a non-uniform radial wall thickness.

A pseudo flame detecting portion detects a presence of a pseudo flame due to disturbance light when a sensor output of a flame sensor is equal to or greater than a pseudo flame threshold value and detects an absence of pseudo flame when the sensor output is equal to or less than another pseudo flame threshold value. The combustion controlling portion monitors the pseudo flame detection result from the pseudo flame detecting portion before an ignition attempt in the combustion equipment and, when the pseudo flame detection result continuously indicates presence of pseudo flame for a first monitoring time, cancels the ignition attempt in the combustion equipment.

A flame detection adjusting portion adjusts a preset reference threshold value based on a sensor output indicating disturbance light obtained from a flame sensor before an ignition attempt in combustion equipment and outputs an obtained adjusted threshold value, and a combustion flame detecting portion detects a presence or an absence of a combustion flame in the combustion equipment based on the sensor output obtained from the flame sensor during combustion in the combustion equipment and an adjusted threshold value.