Flame instability detector

Abstract

Systems and methods for detecting an instability associated with at least one burner are disclosed. A detector measures a signal associated with a characteristic of the at least one burner. The signal is converted to a time-varying signal spectrum using at least one processor. An instability is detected based at least in part on the time-varying signal spectrum. The instability can be detected based on an instability indicator calculated based at least in part on the time-varying signal spectrum. A threshold can be associated with the instability indicator such that an instability is detected when the instability indicator is greater than the threshold.

What is claimed is: 
     
         1 . A method for detecting an instability associated with a at least one burner, comprising:
 obtaining a signal from a detector, the detector measuring at least one characteristic associated with a at least one burner;   converting, using at least one processor, the signal into a time-varying signal spectrum; and   detecting, based at least in part on the time-varying signal spectrum, an instability associated with the at least one burner.   
     
     
         2 . The method of  claim 1 , wherein the instability is detected based on a single channel of data. 
     
     
         3 . The method of  claim 1 , wherein the characteristic comprises a pressure metric. 
     
     
         4 . The method of  claim 3 , wherein the detector comprises a dynamic pressure sensor. 
     
     
         5 . The method of  claim 1 , wherein the characteristic comprises a fluctuation metric. 
     
     
         6 . The method of  claim 5 , wherein the detector comprises a device to capture video frames. 
     
     
         7 . The method of  claim 6 , further comprising converting each video frame into a single scalar to produce a scalar time series signal. 
     
     
         8 . The method of  claim 1 , wherein the characteristic comprises a vibration metric. 
     
     
         9 . The method of  claim 8 , wherein the detector comprises an accelerometer. 
     
     
         10 . The method of  claim 1 , wherein the time-varying signal spectrum comprises a spectrogram. 
     
     
         11 . The method of  claim 1 , wherein the converting the signal comprises using a time-frequency analysis. 
     
     
         12 . The method of  claim 11 , wherein the time-frequency analysis comprises a short-time Fourier transform. 
     
     
         13 . The method of  claim 1 , wherein detecting an instability associated with the at least one burner comprises computing a spectral entropy based on the time-varying signal spectrum. 
     
     
         14 . The method of  claim 1 , wherein detecting an instability associated with the at least one burner comprises determining an instability indicator. 
     
     
         15 . The method of  claim 14 , wherein the instability indicator corresponds to a probability of instability. 
     
     
         16 . The method of  claim 14 , wherein determining the instability indicator comprises converting the time-varying signal into the instability indicator. 
     
     
         17 . The method of  claim 16 , wherein converting the time-varying signal spectrum comprises normalizing the time-varying signal spectrum. 
     
     
         18 . The method of  claim 17 , wherein converting the time-varying signal spectrum further comprises calculating a probability mass function from the normalized time-varying signal spectra. 
     
     
         19 . The method of  claim 18 , wherein converting the time-varying signal spectrum further comprises computing a Shannon entropy of the probability mass function as a function of time. 
     
     
         20 . The method of  claim 19 , wherein the instability indicator comprises an inverse of the spectral entropy. 
     
     
         21 . The method of  claim 14 , detecting an instability further comprises comparing the instability indicator to a threshold value. 
     
     
         22 . The method of  claim 21 , wherein the instability is detected when the instability indicator exceeds the threshold value. 
     
     
         23 . The method of  claim 1 , further comprising providing an alarm when the instability is detected. 
     
     
         24 . The method of  claim 1 , further comprising taking corrective action when the instability is detected. 
     
     
         25 . The method of  claim 24 , wherein the corrective action comprises adjusting an operating property of the at least one burner. 
     
     
         26 . The method of  claim 25 , wherein the corrective action comprises disabling the at least one burner. 
     
     
         27 . The method of  claim 1 , wherein the at least one burner comprises a plurality of burners. 
     
     
         28 . The method of  claim 27 , wherein the detector measures the at least one characteristic of the plurality of burners as a whole. 
     
     
         29 . The method of  claim 28 , wherein detecting the instability comprises detecting an instability associated with the plurality of burners as a whole. 
     
     
         30 . A system for detecting an instability associated with a at least one burner, comprising:
 a detector configured to obtain a signal measuring at least one characteristic associated with a at least one burner;   a converter, coupled to the detector, comprising at least one processor and configured to receive the signal from the detector and convert the signal into a time-varying signal spectrum; and   an instability detector, coupled to the converter, comprising the at least one processor and configured to detect an instability associated with the at least one burner based at least in part on the time-varying signal spectrum.   
     
     
         31 . The system of  claim 30 , configured for use in accordance with any of the methods described in  claims 1  through  29 .