Method and system for determining lean blow out condition for gas turbine combustion cans

A method for determining a lean blow out condition for a combustor, the method comprising:

• gathering dynamic pressure data for each of a plurality of combustor cans;
• determining frequency spectral data from said dynamic pressure data;
• determining a transverse frequency mode based on the frequency spectral data;
• determining a peak within the transverse frequency mode for each of said combustor cans, said peak frequencies indicative of an operating temperature within corresponding combustor cans;
• determining a median frequency for said peak frequencies;
• subtracting said median frequency from said peak frequencies for each of said combustor cans and comparing a resulting differential frequency value therebetween to a calculated first blow out alarm level, said first blow out alarm level corresponding to a frequency less than that of said median frequency;
• generating a first alarm level indication for a given combustor can whenever said differential frequency value for said given combustor can is less than or equal to said first blow out alarm level.

A system for determining a lean blow out condition for a combustor, comprising:

• a sensing device configured for determining acoustical frequency data for the combustor in a direction transverse to a flow within the combustor;
• a computing device configured for determining a combustor flame temperature based on said acoustical frequency data in the direction transverse to the flow within the combustor;
• said computing device further configured for determining an existing fuel/air ratio in said combustor based on said combustor flame temperature, and for comparing said existing fuel/air ratio to a lean blow out fuel/air ratio;
• wherein a lean blow out condition for the combustor is indicated when said existing fuel/air ratio is about equal to said lean blow out fuel/air ratio.