Combustion Instability Active Control Using Periodic Fuel Injection

摘要: Active control using periodic fuel injection has the potential of suppressing combustion instability without radically changing engine design or sacrificing performance. A study is carried out optimal model-based injection. The model developed physically based and includes acoustics, heat-release dynamics, their coupling, dynamics. with fluctuations in flame surface area, as well equivalence ratio, derived. It shown that area coupled velocity drive longitudinal modes to resonance caused by phase-lag whereas ratio can destabilize both bulk time-delay Comparisons are made between predictions several experimental rigs. dynamics proportional two-position (on-off) injectors included model. When overall used, two different designs proposed. first an linear quadratic Gaussian/loop transfer recovery controller, where effect ignored, second a positive forecast which explicitly accounts for delay. Injection at 1) burning zone 2) farther upstream considered. characteristics including bandwidth, authority (pulsed-fuel flow rate), whether it applies discussed. We show increasing bandwidth result improved location 2 compared 1 results tradeoff mixing increased time also noted more successful than on-off because former modulate amplitude phase fuel.