Patent Description:
<CIT> discloses observing combustion conditions in a gas turbine engine. <CIT> discloses a gas turbine with an optical high-temperature pyrometer. Spectrometric techniques may be used to determine an intensity of light as a function of wavelength or frequency and may measure ultraviolet, visible, and infrared radiation emitted by a combustion reaction. These spectral measurements may be used to characterize a flame or combustion reaction, as well as the operation of the equipment in which the flame or combustion reaction is occurring. Spectrometric techniques may be performed using spectral sensing components which may be configured independently from interferometric sensing systems measuring combustion characteristics of the same combustion reaction.

Combustion monitoring may be performed in relation to equipment in which a combustion reaction is present, such as a gas turbine in an oil and gas production environment. A combustion reaction may include a flame, a fuel source, and an oxygen supply such that the fuel source is ignited, creating a flame which persists in the presence of oxygen. Monitoring the condition, quality, and presence of the combustion reaction may provide insight about the conditions of the equipment generating the combustion reaction, the fuel supply, or the oxygen supply.

Combustion monitoring systems may include a fiber optic interferometry sensor positioned with respect to a combustion source and coupled to an interferometer via an optical fiber. By measuring the interferometric data associated with the light that is reflected through the sensor head, characteristics of the combustion reaction, such as the dynamic pressure, static pressure, and temperature, can be determined. As an example, a sensor head can be interfaced to a combustion reaction and can transmit changes in reflected light that are associated with characteristics of the combustion reaction via an optical fiber to a computing device configured with an interferometer.

Traditional fiber optic interferometry sensors used for combustion monitoring can be limited in their ability to determine additional spectral-based combustion characteristics. In one aspect, interferometric combustion monitoring systems can be unable to generate measurements associated with spectral data, such as flame quality and fuel contamination. In another aspect, use of interferometric sensors can be limited under high temperature conditions, such as combustion chambers with operating conditions at or above about <NUM> degrees Celsius. Additional combustion characteristics can be determined using other sensor types, but may require additional penetration points or observation locations into the interior volume of the combustion chamber to perform the combustion monitoring. Deploying multiple sensor types at numerous locations in a combustion chamber requires multiple penetrations through the combustion chamber liner and casing, which can weaken the wall, casing, and liner at the penetration site. In addition, a configuration of multiple penetration sites for different sensors is more expensive to manufacture, maintain and configure as compared to performing combustion monitoring with a sensor configured for penetrating the combustion chamber liner and casing at a single location.

In general, improved systems, devices, and methods are provided herein for performing combustion monitoring using spectral data analysis. A fiber optic interferometry sensor may be configured to include spectral sensing components. The spectral sensing components may include a spectrometer and additional optical fibers to transmit light from the combustion chamber to the spectrometer for use in determining additional combustion characteristics which cannot be determined using interferometric sensing components alone. Additional combustion characteristics that may be determined using the spectral data may include flame temperature, flame supervision, igniter supervision, flame quality, and the presence of contaminants in the fuel source and combustion reaction, or the like. The improved combustion monitoring system may provide further benefits of integrating interferometric sensing components and spectral sensing components into a single sensor head, thereby requiring a single penetration point into a combustion chamber to monitor and collect both interferometric and spectral data associated with the combustion reaction.

In an aspect, a system is provided to perform combustion monitoring using spectral data. The system can include a computing device, including a data processor and a sensor head assembly. The sensor head assembly can include a sensor head affixed to a turbine engine combustion chamber. The sensor head can include a first sized vacuum cavity located in a first position within the sensor head and a diaphragm. The diaphragm can include a first surface positioned opposite the vacuum cavity and a second surface operatively interfaced to an inner portion of the combustion chamber. The sensor head can be configured to measure combustion conditions of a flame in the combustion chamber based on light transmitted via optical fibers. The system can also include an optical sensor interrogator configured on the computing device and coupled to the sensor head via a plurality of optical fibers. The optical sensor interrogator can include an interferometer coupled to the sensor head and configured to determine interferometric data associated with a flame based on light transmitted to and reflected from the sensor head via a first optical fiber. The optical sensor interrogator can also include a first spectrometer coupled to the sensor head and configured to determine spectral data associated with the flame based on light transmitted from the flame and into the sensor head prior to transmission to the spectrometer via a second optical fiber.

One or more of the following features can be combined within the system in any feasible combination. For example, the optical sensor interrogator can be coupled to the sensor head via a single optical fiber, and can further include an optical switch coupled to the interferometer and to the first spectrometer. The computing device can be configured to execute instructions causing the data processor to determine the interferometric data and/or the spectral data based on a pre-determined start time, a pre-determined event, or a pre-determined interval of time since the instructions were previously executed. The sensor head can be affixed to the combustion chamber at a single penetration point. The sensor head can be formed of sapphire or aluminum oxide. At least on optical fiber for the plurality of optical fibers can include a single strand optical fiber or a multi-strand optical fiber. The optical sensor interrogator can include a second spectrometer coupled to the sensor head via a third optical fiber. The first optical fiber can be configured within the sensor head in a horizontal orientation relative the second optical fiber. The first optical fiber can be configured within the sensor head in a vertical orientation relative the second optical fiber. The first optical fiber can be configured centrally within the sensor head and a plurality of second optical fibers can be configured radially within the sensor head relative to the centrally configured first optical fiber.

In another aspect, a method is provided. The method can include transmitting light to a sensor head via a first optical fiber. The sensor head can be affixed to a combustion chamber and can be configured to measure combustion conditions of a flame in the combustion chamber based on the transmitted light. The method can also include receiving light reflected from the sensor head via the first optical fiber. The method can further include determining interferometric data based on the reflected light received via the first optical fiber. The method can also include providing the interferometric data.

One or more of the following features can be combined in any feasible combination. For example, the method can further include determining a dynamic pressure and/or a static pressure of a combustion reaction occurring within the combustion chamber based on the determined interferometric data. Determining the interferometric data can further includes determining a sensor head temperature based on the determined interferometric data. The method can also include receiving light transmitted from the sensor head via a second optical fiber. The method can further include determining spectral data based on the light transmitted from the second optical fiber. The method can also include providing the spectral data. The sensor head can be affixed to the combustion chamber at a single penetration point. The sensor head can be formed of sapphire or aluminum oxide. The method can further include determining one or more of a flame temperature, a flame quality, a presence of a contaminant, an absence of a contaminant, a measure of flame supervision, a measure of igniter supervision, or any combination thereof, based on the determined spectral data. The contaminant can include chlorine, nickel, vanadium, potassium, sodium, sulfur, and/or a combination thereof. The flame quality can be determined as a ratio of two wavelength ranges.

Those skilled in the art will understand that the systems, devices, and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments and that the scope of the present invention is defined solely by the claims.

Combustion can refer to the process of burning one or more materials. Combustion monitoring can be performed to determine characteristics of the combustion process, such as temperature, pressure, etc. of a combustion reaction occurring in a combustion chamber. As an example, a combustion chamber can be a component in a gas turbine in which a fuel and air are mixed and burned. Accurately measuring combustion characteristics within the combustion chamber can facilitate condition monitoring of a combustion process, as the measurements can provide insight into the operational state of the gas turbine equipment, as well as the quality of fuel and air are consumed during the combustion reaction. The accuracy of measured combustion characteristics can be reduced when measurements are taken in a variety of locations using multiple, different sensor systems. Multiple penetration sites can increase the complexity and cost of a combustion monitoring system and can weaken structural aspects of the combustion chamber components, including the combustion chamber wall, liner, and/or casing as compared to combustion monitoring system that utilize sensor configurations which can interface to the combustion chamber at a single penetration site. Thus, operators of combustion monitoring systems can seek to gather as much data about the combustion reaction as possible using minimally invasive techniques that do not require large numbers of sensors to be configured and deployed in multiple locations throughout a combustion chamber. For example, by adding spectral sensing components to a fiber optic interferometry sensor, additional combustion characteristics can be determined without requiring additional penetration points in the combustion chamber liner and the combustion chamber casing for the spectral sensors.

To improve the quality and diversity of measured combustion characteristics, an improved combustion monitoring system is provided and can include spectral data analysis components. By employing spectral analysis components in combination with fiber optic interferometric sensors, additional combustion characteristics can be determined without requiring additional, separately positioned sensors and so that a combustion reaction and/or equipment, fuel or oxygen supplied to the combustion chamber may be accurately characterized in regard to desired operating conditions.

Embodiments of systems, devices, and corresponding methods for performing combustion monitoring using spectral data analysis of a combustion reaction occurring in a combustion chamber associated with a gas turbine are disclosed herein. However, embodiments of the disclosure can be employed for monitoring a combustion reaction in other equipment or combustion environments without limit.

<FIG> illustrates one exemplary embodiment of a combustion monitoring system <NUM> configured to perform combustion monitoring using spectral data analysis. The system <NUM> includes a computing device <NUM>, including a data processor <NUM>, a memory <NUM>, a controller <NUM>, and an optical sensor interrogator <NUM>. The optical sensor interrogator <NUM> is configured to include an interferometer <NUM> and a spectrometer <NUM> and can generate an output <NUM>. The output <NUM> can be provided to a user via a display <NUM> coupled to the computing device <NUM>. In some embodiments, the output can be stored in the memory <NUM>. The combustion monitoring system <NUM> also includes a sensor head assembly <NUM> including a sensor head <NUM> coupled to the computing device <NUM> by a plurality of optical fibers, e.g., optical fibers <NUM> and <NUM>. The combustion chamber <NUM> includes a flame <NUM> generating a combustion reaction and an igniter <NUM> which may be used to initiate the flame <NUM>. The sensor head <NUM> is interfaced to the combustion chamber <NUM> so that a flame <NUM> or a combustion reaction occurring in a combustion chamber <NUM> can be sensed by the sensor head <NUM> through an opening in the combustion chamber liner <NUM>. The sensor head <NUM> includes a diaphragm <NUM> and a vacuum cavity <NUM>.

As shown in <FIG>, a sensor head <NUM> is interfaced with a flame <NUM> or combustion reaction in a combustion chamber <NUM> through a single penetration in the combustion chamber liner <NUM>. The sensor head <NUM> may include a material that is transparent and suitable for transmitting and receiving ultraviolet, visible, and/or infrared radiation from the combustion chamber <NUM>. For example, the sensor head <NUM> may be formed from materials such as sapphire or aluminum oxide. As shown in <FIG>, the sensor head <NUM> may be positioned between a liner <NUM> of the combustion chamber and a casing of the combustion chamber such that the casing is located between the liner <NUM> and the computing device <NUM>. A cooling source may provide a supply of coolant, such as cool air, refrigerated gases, cooling fluids, or the like, to a volume of space that is located between the combustion chamber liner <NUM> and the combustion chamber casing. The sensor head <NUM> can be positioned relative to the combustion chamber <NUM> via a single penetration or opening in the combustion chamber liner <NUM> and casing. The sensor head <NUM> can thus be positioned so as to measure characteristics of the combustion reaction as well as the operation of other components in the combustion chamber <NUM>, such as an igniter <NUM>.

As further shown in <FIG>, the sensor head <NUM> includes a diaphragm <NUM> and a vacuum cavity <NUM>. The thickness, shape, and position of the diaphragm <NUM> may vary. Similarly, the number, shape, and position of the vacuum cavity <NUM> may also vary. The diaphragm <NUM> and vacuum cavity <NUM> may change size and/or shape due to the pressure and temperature fluctuations of the combustion reaction that the sensor head <NUM> is monitoring. As a result of the changes in size and/or shape, the sensor head <NUM> may transmit the reflected light differently causing different interference patterns to be received by the interferometer <NUM>. The sensor head <NUM> is coupled to the computing device <NUM> by a plurality of optical fibers, e.g., optical fibers <NUM> and <NUM>. In some embodiments, one or both of the optical fibers <NUM>, <NUM> may include single strand optical fibers or multi-strand optical fibers. A variety of configurations of optical fibers <NUM>, <NUM> may be coupled to the sensor head <NUM> as will be described in more detail in <FIG>.

As shown in <FIG>, the sensor head <NUM> is coupled to the computing device <NUM> via the optical fibers <NUM>, <NUM>. The computing device <NUM> may include a data processor <NUM>, an input device, a memory <NUM>, a controller <NUM>, a display <NUM>, and a networking or communications interface. The data processor <NUM> can execute computer readable instructions, stored in the memory <NUM>, configured to perform combustion monitoring using spectral and interferometric data analysis. In some embodiments, the computing device <NUM> may be configured in a climate controlled control room. The computing device <NUM> can be configured with an optical sensor interrogator <NUM>, which can include a plurality of optical elements such as an interferometer <NUM>, a spectrometer <NUM>. The optical sensor interrogator <NUM> can further include a data processor and computer readable instructions which when executed cause the optical sensor interrogator <NUM> to generate transmitted light to the sensor head <NUM> and to receive reflected light from the sensor head <NUM>. The interferometer <NUM>, can be a Fabry-Perot interferometer, and can be configured such that interference patterns associated multiple wavelengths of light are used to make precise measurements. For example, in combustion monitoring applications, the interferometer <NUM> may transmit light via a first optical fiber <NUM> to one or more reflective interfaces within the sensor head <NUM>, such as an interface of the vacuum cavity <NUM> or the diaphragm <NUM>. The interferometer <NUM> can measure the interference pattern associated with the light that is reflected by the interfaces and may further determine a dynamic pressure, a static pressure, or a temperature of the combustion reaction or flame <NUM> in the combustion chamber <NUM> based on the interference patterns of the reflected light. The interferometer <NUM> includes a Fizeau wedge used to project an interference pattern associated with the reflected light onto a charge-coupled device in order to determine one or more combustion characteristics based on the interferometric data processed by the interferometer <NUM>. The Fizeau wedge is a wavelength distributor that can be used to distribute the reflected light such that each element of the charge-coupled device is associated with a particular wavelength of the reflected light. Additional detail regarding the operation of the interferometer <NUM> will be described in relation to <FIG>.

As further shown in <FIG>, the optical sensor interrogator <NUM> includes a spectrometer <NUM>. The spectrometer <NUM> may receive light transmitted from the combustion reaction or flame <NUM> after it has passed through the transparent sensor head <NUM> and further passed to the spectrometer <NUM> via a second optical fiber <NUM>. A spectrometer <NUM> is an instrument that can be used for recording and measuring light data, or spectra. The spectrometer <NUM> may be an optical spectrometer capable of separating and measuring spectral components of light and it may show the intensity of light as a function of wavelength or frequency. The optical spectrometer <NUM> may be configured to measure ultraviolet, visible, and infrared light for use in determining combustion characteristics such as flame temperature, flame quality, and/or the presence and type of fuel contaminants, such as nickel, vanadium, potassium, sodium, sulfur, and combinations thereof, which may exist in a combustion reaction or fuel source. Additional details regarding the operation of the spectrometer <NUM> will be described in relation to <FIG>.

<FIG> is a diagram <NUM> illustrating an exemplary embodiment of the combustion monitoring system of <FIG> in operation to perform combustion monitoring using spectral analysis. The combustion monitoring system shown in <FIG> will be used to describe how interferometric data can be measured and used to determine combustion characteristics in more detail.

As shown in <FIG>, the optical sensor interrogator <NUM> includes an interferometer <NUM> coupled to the sensor head <NUM> via optical fiber <NUM>. The interferometer <NUM> may be configured to generate and transmit <NUM> light to the sensor head <NUM> where it may be reflected <NUM> back to the interferometer <NUM> at reflection points within the sensor head <NUM>, such as reflection point A (reference RP-A), reflection point B (reference RP-B), and reflection point C (reference at RP-C). The interferometer <NUM> may transmit <NUM> multi-frequency light or white light to the sensor head <NUM> via optical fiber <NUM> and the interference patterns of the light reflected <NUM> from each of reflection points A, B, and/or C may be used to determine combustion characteristics, such as dynamic pressure, static pressure and/or temperature of the combustion reaction occurring in the combustion chamber <NUM> via interferometric techniques. For example, the diaphragm <NUM> may be exposed to gases and radiation from the combustion chamber <NUM>. As a result, the diaphragm <NUM> may deflect or change shape in a manner that corresponds to the pressure outside the sensor head <NUM>. As the diaphragm <NUM> is displaced, the distance between the diaphragm <NUM> and RP-B of the vacuum cavity <NUM> may change. The distance change may result in changes in the interference patterns of the reflected light that is received at the interferometer <NUM> so that a dynamic pressure and a static pressure of the combustion reaction can be determined based on the changes in the interference patterns. A dynamic pressure may be considered to be the range or magnitude of change of discrete pressure values determined over a period of time. A static pressure may be considered to be pressure measurement associated with a specific point in time and may be used to determine flame supervision.

The sensor head <NUM> may undergo changes in size as the temperature of the combustion reaction changes. For example, under high heat conditions the thickness of the sensor head <NUM> may change causing a change in the distance between RP-A and RP-B. The change in the distance may further cause changes in the interference patterns that are received by the interferometer <NUM>. In this way, the interferometer <NUM> may determine the temperature of the combustion reaction.

<FIG> is a diagram <NUM> illustrating an exemplary embodiment of the combustion monitoring system of <FIG> in operation to perform combustion monitoring using spectral analysis. The combustion monitoring system shown in <FIG> will be used to describe how spectrometry data can be measured and used to determine combustion characteristics in more detail.

As shown in <FIG>, the optical sensor interrogator <NUM> includes a spectrometer 135A coupled to the sensor head <NUM> via optical fiber 165A. The spectrometer 135A may be configured to receive light <NUM> emitted from the combustion chamber <NUM> and transmitted through the sensor head <NUM>. The spectrometer 135A may process the received ultraviolet, visible, and infrared light <NUM> generated by the combustion reaction or an igniter <NUM> flame and digitize the spectrum of light using spectral analysis techniques in order to determine combustion characteristics such as flame temperature, flame and igniter supervision, flame quality, and the presence of contaminants in the fuel source or the combustion chamber <NUM>.

As further shown in <FIG>, the optical sensor interrogator <NUM> includes an additional spectrometer 135B coupled to the sensor head <NUM> via a second optical fiber 165B. The spectrometer 135B may be similarly configured as the spectrometer 135A and may receive light <NUM> emitted from the combustion chamber <NUM> and transmitted through the sensor head <NUM>. The spectrometer 135B may process the received ultraviolet, visible, and infrared light <NUM> generated by the combustion reaction or an igniter <NUM> flame and digitize the spectrum of light using spectral analysis techniques in order to determine combustion characteristics such as flame temperature, flame and igniter supervision, flame quality, and the presence of contaminants in the fuel source or the combustion chamber <NUM>. Each of the spectrometers 135A and 135B is configured independently to digitize a different portion of the spectrum of light transmitted from the sensor head <NUM> in order to determine different combustion characteristics.

<FIG> is a diagram <NUM> illustrating a different exemplary embodiment of a combustion monitoring system in operation to perform combustion monitoring using spectral analysis. The system shown in <FIG> includes similar components as the system <NUM> of <FIG>, except that the optical sensor interrogator <NUM> includes an optical switch <NUM> that is coupled to a single optical fiber, e.g., optical fiber <NUM>. The optical switch <NUM> is also coupled to the interferometer <NUM> and the spectrometer <NUM> which can operate as described in relation to <FIG> and <FIG>, respectively.

As shown in <FIG>, transmitted light <NUM> is received from the sensor head <NUM> by the optical switch <NUM> for performing spectral analysis of the combustion chamber reaction. In such an embodiment, the optical sensor interrogator <NUM> can be coupled to a controller <NUM>, such as a FPGA or microcontroller, which can be coupled to the switch <NUM>. The controller <NUM> can include or receive executable instructions, which when executed cause the controller <NUM> to control the optical switch <NUM> to distribute the transmitted light <NUM> from the sensor head <NUM> to the interferometer <NUM> or the spectrometer <NUM> as appropriate. Similarly, the controller <NUM> can receive the light <NUM> that is generated by the interferometer <NUM> and transmit that light <NUM> to the sensor head <NUM> where it will be reflected at reflection points to create interference patterns, as described in relation to <FIG>, before being received by the optical switch <NUM> and transmitted to the interferometer <NUM> for interferometric analysis.

A benefit to the configuration of the combustion monitoring system <NUM> shown in <FIG>, is that the single point of penetration in the combustion chamber liner <NUM> and casing can be utilized to perform both interferometric and spectral analysis techniques and thereby optimize space constraints within the equipment being monitored. In addition, single penetration sites, and the hardware included therein, which may have been previously used for spectral analysis can be modified or reconfigured with a sensor head assembly <NUM> and a combustion monitoring system that can be configured for interferometric and spectral analysis.

<FIG> are diagrams illustrating exemplary embodiments of a sensor head <NUM> included in a system configured to perform combustion monitoring using spectral analysis, such as the system <NUM> shown and described in relation to <FIG>. <FIG> illustrate two exemplary configurations of the sensor head <NUM>. Each configuration shows the face of the sensor head <NUM> viewed from the perspective of inside the combustion chamber <NUM>, looking at the face of the sensor head <NUM> as it would be interfaced with the combustion chamber <NUM> at its single point of penetration.

As shown in each of <FIG>, the sensor head <NUM> includes the diaphragm <NUM> and a plurality of optical fibers, such as optical fiber <NUM> and optical fiber <NUM>. A variety of diaphragm <NUM> and vacuum cavity <NUM> shapes are contemplated in the present disclosure. The diaphragm <NUM> and corresponding vacuum cavity (not explicitly shown, but which can be interpreted as positioned immediately behind the diaphragm <NUM>) are illustrated showing the diaphragm <NUM> as a surface which covers the vacuum cavity. In operation, the surface of the diaphragm <NUM> can deflect into the vacuum cavity (e.g., along a Z-axis or in a direction that corresponds with a direction into or out of the page on which <FIG> are presented) as pressure fluctuations within the combustion chamber <NUM> occur. Generally the diaphragm <NUM> shape may correspond to the shape of the vacuum cavity <NUM>, and vice versa. Additionally, as will be described in relation to <FIG>, in some embodiments, the sensor head <NUM> may be configured with a plurality of second optical fibers 165A-D. For example, the sensor head <NUM> may include multiple optical fiber <NUM>, each coupling the sensor head <NUM> to one or more spectrometers <NUM>.

As shown in <FIG>, a circular-shaped sensor head <NUM> is illustrated and includes a circular shaped diaphragm <NUM>. The first optical fiber <NUM> is positioned in relation to the diaphragm <NUM> and the second optical fiber <NUM> is positioned independent from the location of the diaphragm <NUM> (and the vacuum cavity). A variety configurations of the diaphragm <NUM> (and the vacuum cavity <NUM>) and the optical fibers <NUM>, <NUM> may be contemplated in the sensor head <NUM> design. As shown in <FIG>, the optical fibers <NUM>, <NUM> are arranged in a vertical orientation relative to each other. In some embodiments, the diaphragm <NUM> (and the vacuum cavity <NUM>) and the optical fibers <NUM>, <NUM> may be arranged in a horizontal orientation relative to each other. In some embodiments, the circular sensor head <NUM> may be sized include a <NUM>" outside diameter. In other embodiments, the outside diameter of the sensor head <NUM> may be selected from the range of about <NUM>" to about <NUM>" (e.g., about <NUM>", <NUM>", <NUM>", <NUM>", or <NUM>").

As shown in <FIG>, a circular-shaped sensor head <NUM> is illustrated and includes a centrally positioned circular diaphragm <NUM> with a plurality of second optical fibers 165A-D arranged peripherally around the diaphragm <NUM> and the first optical fiber <NUM>. For example, optical fibers 165A, 165B, 165C, and 165D are arranged at positions that are <NUM> degrees from one another around optical fiber <NUM>. A variety of second optical fiber <NUM> positions may be achieved and are not limited by the positions shown in <FIG>. In some embodiments, the sensor head <NUM> may be configured with one or more second optical fibers <NUM> (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> second optical fibers <NUM>).

<FIG> illustrates a flow diagram describing one exemplary embodiment of a method <NUM> for performing combustion monitoring using interferometric data by the combustion monitoring system <NUM> of <FIG> as described herein.

In operation <NUM>, the interferometer <NUM> transmits light to a sensor head <NUM> via a first optical fiber <NUM>. The interferometer <NUM> transmits multi-frequency or white light through the first optical fiber <NUM> to the sensor head <NUM>.

In operation <NUM>, the interferometer <NUM> receives light reflected from the sensor head <NUM> via the first optical fiber <NUM>. The transmitted light passes through the transparent sensor head <NUM> and is reflected from any number of interfaces or boundaries within the sensor head <NUM>, such as the location where the first optical fiber <NUM> is interfaced to the sensor head <NUM> (e.g., reflection point A of <FIG>), a first vacuum cavity <NUM> interface (e.g., reflection point B of <FIG>), and a second vacuum cavity <NUM> interface located in relation to the diaphragm <NUM> interface (e.g., reflection point C of <FIG>).

In operation <NUM>, the interferometer <NUM> determines interferometric data based on the reflected light received via the first optical fiber <NUM>. The combustion reaction may generate pressure dynamics or variations which cause the diaphragm <NUM> to deflect such that the transmitted light reflected at the reflection points produces interference patterns which the interferometer <NUM> may use to determine the distance associated with the deflection. The distances may be further processed by the interferometer <NUM> to determine the dynamic and static pressure of the combustion reaction. Similarly, the interferometer <NUM> may determine the temperature of the sensor head <NUM> by measuring changes in distances between the reflection points due to heat that is absorbed by the sensor head <NUM>. The changes in distances will create interference patterns that can be analyzed using interferometric techniques to determine the sensor head temperature. Sensor head temperature can thus be derived from the changes in distance using coefficients of thermal expansion. The interferometric data can be provided. For example, the interferometric data can be provided to the computing device <NUM>, stored in a memory <NUM> of the computing device, and/or provided via an output device <NUM> coupled to the computing device <NUM>, such as a display.

<FIG> illustrates a flow diagram describing one exemplary embodiment of a method <NUM> for performing combustion monitoring using spectral data by the combustion monitoring system <NUM> of <FIG> as described herein.

In operation <NUM>, the spectrometer <NUM> receives light from the sensor head <NUM> via a second optical fiber <NUM>. As the combustion reaction occurs in the combustion chamber <NUM>, light is radiated into the second optical fiber <NUM> and transmitted to the spectrometer <NUM> where it is received for spectral analysis. The received light includes ultraviolet, visible, and infrared light that is generated by the combustion reaction.

In operation <NUM>, the spectrometer <NUM> determines spectral data based on the light transmitted from the second optical fiber <NUM>. The light received in operation <NUM> is digitized by the spectrometer <NUM> and the spectral signatures of the received light are used to determine characteristics of the combustion reaction. The spectral data can be used to determine combustion characteristics such as flame supervision, igniter supervision, flame temperature, contaminants that may be present in fuel or in the combustion chamber, and flame quality.

Determining flame supervision may include processing the received ultraviolet light to determine the presence or absence of a flame (e.g., an "on/off" indication), as well as determining the intensity of a flame. In some embodiments, threshold values may be used to determine the presence or absence of a flame or levels of flame intensity.

Determining igniter supervision may include processing received ultraviolet and/or visible light to determine the presence and/or absence (e.g., an "on/off" indication) of a spark from an igniter <NUM> of the combustion chamber <NUM>, as well as determining the intensity of the spark on the igniter <NUM>. In some embodiments, threshold values may be used to determine the presence or absence of the igniter spark or levels of igniter spark intensity.

Determining flame temperature may include analyzing wavelength ranges of the received light over time and determining a corresponding trend in temperature associated with the time-series of wavelength data.

Determining the presence of contaminants in the fuel or within the combustion chamber <NUM> may include analyzing visible and infrared light for peaks in the spectral signatures that may correspond to particular contaminants. For example, sulfur, chlorine, nickel, sodium, vanadium, or other elemental contaminants, may generate unique spectral signatures in visible and infrared light as they are combusted in the combustion reaction.

Determining flame quality may include analyzing received ultraviolet and infrared light to determine if the flame or combustion reaction is efficient or inefficient. Flame quality may be determined as a ratio of two wavelength ranges.

In some embodiments, the spectral data can be provided to the computing device <NUM>, stored in a memory <NUM> of the computing device <NUM>, and/or provided via an output device <NUM> coupled to the computing device <NUM>, such as a display.

In some embodiments, additional spectral measurements may be determined using additional or alternative spectral analysis techniques to those described above.

Exemplary technical effects of the systems, devices, and methods described herein include, by way of non-limiting example, enhanced combustion monitoring of a combustion reaction in a combustion chamber using a single penetration site. In one aspect, the combustion monitoring is performed using a sensor head disposed within the single penetration site such that a plurality of optical fibers can be integrated with the sensor head to measure interferometric and spectral data generated by the combustion reaction. In another aspect, the sensor head is coupled to an interrogator configured to process the interferometric and spectral data in a single computing device. In this manner, a broad range of combustion characteristics can be achieved via a sensor head positioned in a single point of penetration within a combustion chamber to provide a more robust combustion monitoring system.

To provide for interaction with a user, the subject matter described herein can be implemented on a computer having a display device, such as display <NUM>, e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor, for displaying information to the user and a keyboard and a pointing device, (e.g., a mouse or a trackball), by which the user can provide input to the computer.

Certain exemplary embodiments are described to provide an overview of the principles of the structure, function, manufacture, and use of the systems, devices, and methods disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. The features illustrated or described in connection with one exemplary embodiment can be combined with the features of other embodiments. Such modifications and variations are intended to be included within the scope of the present invention.

Claim 1:
A combustion monitoring system (<NUM>) comprising:
a computing device (<NUM>), including a data processor (<NUM>);
a sensor head assembly (<NUM>) including a sensor head (<NUM>) affixed to a turbine engine combustion chamber (<NUM>), the sensor head (<NUM>) comprising
a first sized vacuum cavity (<NUM>) located in a first position within the sensor head (<NUM>), and
a diaphragm (<NUM>) including a first surface positioned opposite the vacuum cavity (<NUM>) and a second surface operatively interfaced to an inner portion of the combustion chamber,
wherein the sensor head (<NUM>) is configured to measure combustion conditions of a flame in the combustion chamber based on light transmitted via optical fibers; and
an optical sensor interrogator (<NUM>) configured on the computing device (<NUM>) and coupled to the sensor head (<NUM>) via a plurality of optical fibers, the optical sensor interrogator (<NUM>) characterized by including
an interferometer (<NUM>) coupled to the sensor head (<NUM>) and configured to determine interferometric data associated with the flame based on light transmitted to and reflected from the sensor head (<NUM>) via a first optical fiber (<NUM>), the interferometer (<NUM>) including a Fizeau wedge to project an interference pattern associated with the reflected light onto a charge-coupled device in order to determine one or more combustion characteristics based on the interferometric data, and
first and second spectrometers (135A, 135B) coupled to the sensor head (<NUM>) and configured to determine spectral data associated with the flame based on light transmitted from the flame and into the sensor head (<NUM>) prior to transmission to the spectrometers (135A, 135B) via second optical fibers (165A, 165B), each of the spectrometers (135A, 135B) being configured independently to digitize a different portion of the spectrum of light transmitted from the sensor head (<NUM>) in order to determine different combustion characteristics.