# US 7,942,038 B2 · Systems and methods of monitoring acoustic pressure to detect a flame condition in a gas turbine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,942,038 B2 - Document ID: US7942038B2 - Status: Granted - Kind: B2 - Application number: 12/356,828 - Filed: 2009-01-21 - Published: 2010-07-22 - Granted: 2011-05-17 - Earliest claimed: 2009-01-21 - Assignees: General Electric Company - Inventors: Willy Steve Ziminsky; Anthony Wayne Krull; Timothy Andrew Healy; Ertan Yilmaz - Web page: https://patentgrep.com/patent/US7942038B2 ## CPC - F23N 5/16: using noise-sensitive detectors - F23N 5/242: {using electronic means} - F23R 3/286: {having fuel-air premixing devices (F23R3/30 takes precedence)} - F23N 2225/04: pressure - F23N 2231/28: preventing flash-back or blow-back - F23N 2241/20: Gas turbines - F23R 2900/00002: Gas turbine combustors adapted for fuels having low heating value [LHV] - F23R 2900/00013: Reducing thermo-acoustic vibrations by active means - F23R 2900/00016: Retrofitting in general, e.g. to respect new regulations on pollution - F23N: REGULATING OR CONTROLLING COMBUSTION (control devices specially adapted for combustion apparatus in which combustion takes place in a fluidised bed of fuel or other particles F23C10/28; condition responsive controls for regulating combustion in domestic stoves with open fires for solid fuel F24B1/187) - F23R: GENERATING COMBUSTION PRODUCTS OF HIGH PRESSURE OR HIGH VELOCITY, e.g. GAS-TURBINE COMBUSTION CHAMBERS (fluidised bed combustion apparatus specially adapted for operation at superatmospheric pressures F23C10/16) ## Abstract A method may detect a flashback condition in a fuel nozzle of a combustor. The method may include obtaining a current acoustic pressure signal from the combustor, analyzing the current acoustic pressure signal to determine current operating frequency information for the combustor, and indicating that the flashback condition exists based at least in part on the current operating frequency information. ## Claims ### Claim 1 A method of detecting a flashback condition in a fuel nozzle of a combustor, the method comprising: obtaining a current acoustic pressure signal from the combustor; analyzing the current acoustic pressure signal to determine current operating frequency information for the combustor; and detecting that the flashback condition exists based at least in part on the current operating frequency information. ### Claim 2 (depends on 1) The method of claim 1, wherein obtaining a current acoustic pressure signal from the combustor comprises detecting acoustic pressure waves within the combustor with a device that comprises one or more of the following: a sensor, a probe, a transducer, and a microphone. ### Claim 3 (depends on 1) The method of claim 1, wherein analyzing the current acoustic pressure signal comprises performing a signal processing technique operable to represent the current acoustic pressure signal in the frequency domain. ### Claim 4 (depends on 3) The method of claim 3, wherein the signal processing technique is selected from the group consisting of: fast Fourier transform, short-term Fourier transform, windowed Fourier transform, wavelet transform, and Laplace transform. ### Claim 5 (depends on 1) The method of claim 1, further comprising: obtaining a baseline acoustic pressure signal from the combustor during normal operation; and analyzing the baseline acoustic pressure signal to determine baseline operating frequency information for the combustor. ### Claim 6 (depends on 5) The method of claim 5, wherein detecting that the flashback condition exists comprises: comparing the current operating frequency information to the baseline operating frequency information; and indicating that the flashback condition exists in response to one or more dominant frequencies of the current operating frequency information differing from dominant frequencies of the baseline operating frequency information. ### Claim 7 (depends on 1) The method of claim 1, further comprising: obtaining an abnormal acoustic pressure signal from the combustor during development of a flashback condition; and analyzing the abnormal acoustic pressure signal to determine abnormal operating frequency information for the combustor. ### Claim 8 (depends on 7) The method of claim 7, wherein detecting that the flashback condition exists comprises: comparing the current operating frequency information to the abnormal operating frequency information; and indicating that the flashback condition exists in response to one or more dominant frequencies of the current operating frequency information substantially matching one or more dominant frequencies of the abnormal operating frequency information. ### Claim 9 (depends on 1) The method of claim 1, wherein analyzing the current acoustic pressure signal further comprises filtering the acoustic pressure signal. ### Claim 10 (depends on 1) The method of claim 1, wherein: analyzing the current acoustic pressure signal further comprises determining current operating frequency and amplitude information for the combustor; and detecting that the flashback condition exists in the combustor comprises comparing the current operating frequency and amplitude information to one or more of the following: baseline frequency and amplitude information associated with normal operation of the combustor and abnormal operating frequency and amplitude information associated with a flashback condition in the combustor. ### Claim 11 A system for detecting a flashback condition, the system comprising: a sensor operable to detect an acoustic pressure signal in a combustor; and a controller operable to: analyze the detected acoustic pressure signal to identify a current operating frequency; and detecting a flashback condition exists in response to the current operating frequency falling outside of a range of baseline frequencies associated with normal combustor operation. ### Claim 12 (depends on 11) The system of claim 11, wherein the sensor further comprises a transducer. ### Claim 13 (depends on 11) The system of claim 11, wherein the sensor is positioned in a combustor chamber of the combustor. ### Claim 14 (depends on 11) The system of claim 11, wherein the sensor is associated with an existing combustion dynamics monitoring probe. ### Claim 15 (depends on 11) The system of claim 11, wherein the controller comprises a signal processor operable to determine one or more frequencies present in the acoustic pressure signal. ### Claim 16 A system for detecting a flame condition, the system comprising: a sensor operable to detect an acoustic pressure signal in a combustor; and a controller operable to: analyze the detected acoustic pressure signal to identify a current operating frequency; and detecting a flashback condition exists in response to the current operating frequency falling within a range of abnormal frequencies associated with a flashback condition. ### Claim 17 (depends on 16) The system of claim 16, wherein the sensor further comprises a transducer. ### Claim 18 (depends on 16) The system of claim 16, wherein the sensor is positioned in a combustor chamber of the combustor. ### Claim 19 (depends on 16) The system of claim 16, wherein the sensor is associated with an existing combustion dynamics monitoring probe. ### Claim 20 (depends on 16) The system of claim 16, wherein the controller comprises a signal processor operable to determine one or more frequencies present in the acoustic pressure signal.