Abstract:
PROBLEM TO BE SOLVED: To overcome any difficulty in attainment of a tunable diode laser absorption spectroscopy (TDLAS).SOLUTION: A multiplexer 16 optically-connected with outputs of two or more diode lasers 12 having selected laser oscillating frequencies is optically-connected with an optical fiber on pitch side. A multiplexed laser beam is transmitted to a pitch optical component 20 associated with a process chamber 22 through the pitch side optical fiber. The pitch optical component 20 is oriented so as to radiate a multiplexed laser output through inside the process chamber. A catch optical component 24 receives the radiated multiplexed laser output. The catch optical component 24 is optically-connected with an optical fiber transmitting the multiplexed laser output to a demultiplexer 28. The demultiplexer 28 demultiplexes a laser beam to optically-connect the selected laser oscillating frequency of the laser beam with a detector 25. This detector has sensitivity to one of the selected laser oscillating frequencies.
Abstract:
PROBLEM TO BE SOLVED: To provide method and system for monitoring and control of combustion that overcome any difficulty in attainment of wavelength-variable diode laser absorption spectroscopy (TDLAS). SOLUTION: In this method, multiplexer 16 optically-connected with output of two or more diode lasers 12 having selected laser oscillating frequencies is optically-connected with optical fiber on pitch side. Multiplexed laser beam is transmitted to pitch optical component 20 associated with process chamber 22 through the pitch side optical fiber. The pitch optical component 20 is oriented so as to radiate multiplexed laser output through inside the process chamber. A catch optical component 24 receives the above radiated multiplexed laser output. The catch optical component 24 is optically-connected with the optical fiber transmitting the multiplexed laser output to demultiplexer 28. The demultiplexer 28 demultiplexes laser beam to optically-connect the selected laser oscillating frequency of the beam with a detector 25. This detector has sensitivity to one of the selected laser oscillating frequencies. COPYRIGHT: (C)2010,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To solve the problem for achieving the tunable diode laser absorption spectroscopy (TDLAS). SOLUTION: A multiplexer (16) optically coupled to the outputs of more than one diode lasers (12) having selected lasing frequencies, is further optically coupled to a pitch side optical fiber. Multiplexed laser light is transmitted through the pitch side optical fiber to pitch optics (20) operatively associated with a process chamber (22). The pitch optics (20) are oriented to project multiplexed laser output through the process chamber. Also catch optics (24) receive the projected multiplexed laser output. The catch optics (24) are optically coupled to the optical fiber which transmits the multiplexed laser output to a demultiplexer (28). The demultiplexer (28) demultiplexes the laser light and optically couples to detectors (25) the selected lasing frequencies of light. Each of detectors (25) is sensitive to one of the selected lasing frequencies. COPYRIGHT: (C)2009,JPO&INPIT
Abstract:
A method of calibrating an absorption spectroscopy measurement wherein the calibration method includes projecting laser light through a sample of a first quantity of a gas of interest and a second irrelevant quantity of a spectroscopically identical or similar gas (10). The first and second spectroscopic absorptions of the laser light are measured over specific first and second absorption lines. A functional relationship is determined between the first and second measured spectroscopic absorptions and two unknown variables. The function relationships may then be simultaneously solved to determine one or both unknown variables and thereby obtain a measurement relating to the first quantity of the gas of interest, calibrated for the second irrelevant quantity of gas.
Abstract:
A method of absorption spectroscopy including obtaining absorption data at multiple wavelengths along more than one line-of-sight path through a quantity of gas of interest. The method further includes identifying more than one temperature and gas species concentration bin along the multiple line-of-sight paths and creating a map of temperature and gas species concentration. The map thus created will have at least two-dimensional information derived from select temperature and gas species concentration bins identified along more than one line-of-sight path. Apparatus for implementing the above method is also disclosed.
Abstract:
An apparatus and methods for measuring combustion parameters in the measurement zone of a gas turbine engine. The measurement zone is defined as being between an outer casing and an engine component having a reflecting surface inside the outer casing. The apparatus comprises a laser generating a transmitting beam of light of a select wavelength and a multimode transmitting fiber optically coupled to the laser. A transmitting optic is optically coupled to the multimode optical fiber for transmitting the beam into the measurement zone. The reflecting surface is configured to provide a Lambertian reflection. A receiving optic is positioned to receive the Lambertian reflection. Means are provided in operative association with the multimode transmitting fiber for averaging modal noise induced signal level variation of light propagating within the multimode transmitting fiber.
Abstract:
A method of calibrating an absorption spectroscopy measurement wherein the calibration method includes projecting laser light throu a sample of a first quantity of a gas of interest and a second irrelevant quantity of a spectroscopically identical or similar gas (10). The first and second spectroscopic absorptions of the laser light are measured over specific firs t and second absorption lines. A functional relationship is determined between the first and second measured spectroscopic absorptions and two unknown variables. The function relationships may then be simultaneously solved to determine one or both unknown variables and thereby obtain a measurement relati to the first quantity of the gas of interest, calibrated for the seco nd irrelevant quantity of gas.
Abstract:
An apparatus and methods for measuring combustion parameters in the measurement zone of a gas turbine engine. The measurement zone is defined as being between an outer casing and an engine component having a reflecting surface inside the outer casing. The apparatus comprises a laser generating a transmitting beam of light of a select wavelength and a multimode transmitting fiber optically coupled to the laser. A transmitting optic is optically coupled to the multimode optical fiber for transmitting the beam into the measurement zone. The reflecting surface is configured to provide a Lambertian reflection. A receiving optic is positioned to receive the Lambertian reflection. Means are provided in operative association with the multimode transmitting fiber for averaging modal noise induced signal level variation of light propagating within the multimode transmitting fiber.
Abstract:
A method of absorption spectroscopy including obtaining absorption data a t multiple wavelengths along more than one line-of-sight path through a quan tity of gas of interest. The method further includes identifying more than o ne temperature and gas species concentration bin along the multiple line-of- sight paths and creating a map of temperature and gas species concentration. The map thus created will have at least two-dimensional information derived from select temperature and gas species concentration bins identified along more than one line-of-sight path. Apparatus for implementing the above meth od is also disclosed.
Abstract:
A method of sensing a process utilizing a sensing apparatus consisting of more than one diode laser having select lasing frequencies, a multiplexer optically coupled to the outputs of the diode lasers with the multiplexer being further optically coupled to a pitch side optical fiber. Multiplexed laser light is transmitted through the pitch side optical fiber to a pitch optic operatively associated with a process chamber which may be a combustion chamber or the boiler of a coal or gas fired power plant. The pitch optic is oriented to project multiplexed laser output through the process chamber. Also operatively oriented with the process chamber is a catch optic in optical communication with the pitch optic to receive the multiplexed laser output projected through the process chamber. The catch optic is optically coupled to an optical fiber which transmits the multiplexed laser output to a demultiplexer. The demultiplexer demultiplexes the laser light and optically couples the select lasing frequencies of light to a detector with the detector being sensitive to one of the select lasing frequencies.