Optical spectrometer and method for combustion flame temperature determination
AssigneeGeneral Electric Company
InventorsDale Marius Brown, Kanin Chu
Life of this patent
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Abstract
A solid state optical spectrometer for combustion flame temperature determination comprises: a first photodiode device for obtaining a first photodiode signal, the first photodiode device comprising a silicon carbide photodiode and having a range of optical responsivity within an OH band; a second photodiode device for obtaining a second photodiode signal, the second photodiode device comprising a silicon carbide photodiode and a filter, the second photodiode device having a range of optical responsivity in a different and overlapping portion of the OH band than the first photodiode device; and a computer for obtaining a ratio using the first and second photodiode signals and using the ratio to determine the combustion flame temperature.
Claims13
A solid state optical spectrometer for combustion flame temperature determination, the spectrometer comprising:
- a first photodiode device for obtaining a first photodiode signal, the first photodiode device comprising a silicon carbide photodiode and having a range of optical responsivity within an OH band ranging from about 260 nm to about 350 nm;
- a second photodiode device for obtaining a second photodiode signal, the second photodiode device comprising a silicon carbide photodiode and a filter, the second photodiode device having a range of optical responsivity in a different and overlapping portion of the OH band than the first photodiode device;
- a computer for obtaining a ratio using the first and second photodiode signals and using the ratio to determine the combustion flame temperature.
A solid state optical spectrometer for combustion flame temperature determination, the spectrometer comprising:
- a first photodiode device for obtaining a first photodiode signal, the first photodiode device comprising a silicon carbide photodiode and having a range of optical responsivity within an OH band;
- a second photodiode device for obtaining a second photodiode signal, the second photodiode device comprising a silicon carbide photodiode and a filter, the second photodiode device having a range of optical responsivity in a different and overlapping portion of the OH band than the first photodiode device:
- a computer for obtaining a ratio using the first and second photodiode signals and using the ratio to determine the combustion flame temperature,
- wherein the computer includes a look-up table for using the ratio to determine the combustion flame temperature,
- wherein the look-up table is a took-up table fabricated by performing the following calculations at a plurality of different temperatures:
- multiplying each of a first set of spectral line strengths (Sj) associated with respective wavelengths (j) by a respective quantum mechanical form of the Black body radiation law (Rj) and by a respective photodiode responsivity (Xj) and summing the multiplied line strengths into a respective first summation;
- multiplying each of a second set of spectral line strengths (Si) associated with respective wavelengths (i) by a respective quantum mechanical form of the Black body radiation law (Ri) and by a respective photodiode responsivity (Xi) and summing the multiplied line strengths into a respective second summation;
- and
- dividing one of the first and second summations by the other of the first and second summations.
A solid state optical spectrometer for combustion flame temperature determination, the spectrometer comprising:
- a first photodiode device for obtaining a first photodiode signal, the first photodiode device comprising a silicon carbide photodiode and having a range of optical responsivity within an OH band;
- a second photodiode device for obtaining a second photodiode signal, the second photodiode device comprising a silicon carbide photodiode and a filter, the second photodiode device having a range of optical responsivity in a different and overlapping portion of the OH band than the first photodiode device;
- a computer for obtaining a ratio using the first and second photodiode signals and using the ratio to determine the combustion flame temperature,
- wherein the computer includes a look-up table for using the ratio to determine the combustion flame temperature,
- wherein the look-up table is a look-up table fabricated by performing the following calculations at a plurality of different temperatures:
- multiplying each of a first set of spectral line strengths (Sj) associated with respective wavelengths (j) by a respective quantum mechanical form of the Black body radiation law (Rj) and by a respective photodiode responsivity (Xj) and summing the multiplied line strengths into a respective first summation;
- multiplying each of a second set of spectral line strengths (Si) associated with respective wavelengths (i) by a respective quantum mechanical form of the Black body radiation law (Ri), by a respective photodiode responsivity (Xi) and by a respective optical transparency (Yi) of the filter, and summing the multiplied line strengths into a respective second summation;
- and
- dividing one of the first and second summations by the other of the first and second summations.
A solid state optical spectrometer for combustion flame temperature determination, the spectrometer comprising:
- a first photodiode device for obtaining a first photodiode signal, the first photodiode device comprising a silicon carbide photodiode and having a range of optical responsivity within an OH band ranging from about 260 nm to about 350 nm;
- a second photodiode device for obtaining a second photodiode signal, the second photodiode device comprising a silicon carbide photodiode and an aluminum gallium nitride filter, the second photodiode device having a range of optical responsivity in a different and overlapping portion of the OH band than the first photodiode device;
- a computer for obtaining a ratio using the first and second photodiode signals and using the ratio to determine the combustion flame temperature.
A method for combustion flame temperature determination comprising:
- obtaining a first photodiode signal using a first photodiode device comprising a silicon carbide photodiode and having a range of optical responsivity within an OH band ranging from about 260 nm to about 350 nm;
- obtaining a second photodiode signal by using a second photodiode device comprising a silicon carbide photodiode and a filter, the second photodiode device having a range of optical responsivity in a different and overlapping portion of the OH band than the first photodiode device;
- and
- obtaining a ratio using the first and second photodiode signals and using the ratio to determine the combustion flame temperature.
Dependencies are inferred from the claim text.