EFFECTS OF CYCLE OPERATING-CONDITIONS ON COMBUSTOR PERFORMANCE

To mitigate the environmental impact of next-generation gas turbine co mbustors, the emission performance at each condition throughout the lo ad duty cycle must be optimized. Achieving this with a single combusto r geometry may not be possible. Rather, the mixing processes and airfl ow splits must likely be modified as a function of load in order to (1 ) abate the emission of oxides of nitrogen, (2) maintain combustion ef ficiency, and (3) preclude lean blow-out over the entire duty cycle. T he present study employs a model combustor to evaluate combustor perfo rmance as a function of load and explore the application of variable g eometry to optimize performance at each condition. A parametric variat ion of flow splits is conducted at each load condition by independentl y adjusting the primary jet area and swirler choke area. The resultant impact on combustor performance is measured and quantified in terms o f a cost function. The cost function is defined to increase with impro ving combustor performance (e.g., improving combustion efficiency and/ or declining NOx emissions). Cycle operating conditions are found to a lter the response mappings of efficiency and NOx. As a result, the opt imal configuration of the combustor changes as the load is varied over the duty cycle. The results provide guidance on the application of ac tive control.