Advanced Sensor Approaches for Monitoring and Control of Gas Turbine Combustors

This report describes sensing strategies that were developed for monitoring the health and performance of gas turbine combustors. Sensor systems based on these approaches enable control and monitoring systems that improve combustor reliability and operability, achieve optimal performance (e.g., lower NOx emissions) over extended periods of time, reduce maintenance, prevent forced outages, and increase engine life. Specifically, we developed methods to: 1) sense imminent loss of static combustor stability, e.g., precursors to flame loss or lean blow out; 2) determine local fuel-air ratio and heat release variations that can arise from mixedness variations; and 3) sense the proximity of the combustor to its dynamic stability margin, i.e., detecting how close the system is to the point where detrimental combustion instabilities would occur. The approaches involve a combination of nonintrusive optical and acoustic sensing, as well as ion concentration probes. The methods were evaluated for their applicability in natural gas and syngas fueled combustors. In addition to tests in our laboratory, field tests of the stability margin sensing were pursued with industrial partners.