Claims
- 1. An apparatus for detecting flashback occurrences in a premixed combustor system including at least one fuel nozzle, the apparatus comprising:
- at least one photodetector;
- at least one fiber optic element coupled between the at least one photodetector and a test region of the combustor system wherein a respective flame of the at least one fuel nozzle is not present under normal operating conditions; and
- a signal processor for monitoring a signal of the at least one photodetector.
- 2. The apparatus of claim 1 wherein the at least one fiber optic element comprises a single optical fiber for sensing the respective flame and coupling the test region and the photodetector.
- 3. The apparatus of claim 2 wherein the single optical fiber comprises an optical fiber having a diameter ranging from about 100 micrometers to about 200 micrometers.
- 4. The apparatus of claim 2 further including an optical fiber device comprising:
- a cylindrically shaped bullet tip having a hole extending axially therethrough and front and back bullet tip ends, the single optical fiber extending through the bullet tip;
- a capillary sleeve situated around a portion of the single optical fiber; and
- a molding compound supporting the single optical fiber and the capillary sleeve in the bullet tip.
- 5. The apparatus of claim 1 wherein the at least one fiber optic element includes at least one optical fiber positioned within a protective tube.
- 6. The apparatus of claim 5, wherein the at least one fiber optic element includes at least two fiber optic elements coupled to the test region.
- 7. The apparatus of claim 5, wherein the combustor system is situated in an engine compartment and wherein the at least one optical fiber and the protective tube have lengths sufficient to situate the at least one photodetector outside the engine compartment.
- 8. The apparatus of claim 1 wherein the at least one fuel nozzle comprises a plurality of fuel nozzles, the at least one photodetector comprises a plurality of photodetectors, and the at least one fiber optic element comprises a plurality of fiber optic elements, each fiber optic element coupled between a respective one of the plurality of photodetectors and a respective test region of a respective one of the plurality of fuel nozzles.
- 9. The apparatus of claim 1 wherein the at least one fuel nozzle comprises a plurality of fuel nozzles and the at least one fiber optic element comprises a plurality of fiber optic elements, each fiber optic element coupled between the at least one photodetector and a respective test region of a respective one of the plurality of fuel nozzles.
- 10. The apparatus of claim 1, wherein the signal comprises a plurality of digital signals, and further including an analog to digital converter coupled between the photodetector and the signal processor for converting an analog signal of the photodetector into the plurality of digital signals.
- 11. The apparatus of claim 10, wherein the signal processor includes:
- a decimation element for integrating a selected number of the plurality of digital signals to provide sample data;
- a filter correlation element for correlating the sample data with a fixed step response; and
- a false alarm filter for using the correlated sample data to prevent false alarms.
- 12. The apparatus of claim 11, further including:
- an RMS calculator for normalizing the sample data; and
- a high pass filter for filtering the normalized sample data, wherein the false alarm filter uses both the correlated sample data and the filtered normalized sample data for preventing false alarms.
Parent Case Info
This application claims domestic priority under 35USC 119(e), based upon provisional application Ser. No. 60/052,853 filed on Jun. 24, 1996.
Government Interests
This invention was made with US Government support under Contract Number NAS327235 awarded by NASA. The Government has certain rights in the invention.
US Referenced Citations (5)