Variable Fuel Placement Injector Development

The operational uncertainty of lean premixed prevaporized technology coupled with the weight and complexity penalties associated with double annular aerocombustors has led to the emergence of the single annular, lean-burn variable fuel placement fuel injector. QinetiQ, in partnership with Smiths Aerospace, are involved in the development of an in-burner-staged airblast fuel injector, which produces two autonomous recirculation zones allowing for low NO_x control over a wide turndown range. Various prototype fuel injectors have been tested in an angled effusion cooled combustor liner at up to 13 bar and 900 K. An idle power efficiency of over 99.5% was achieved with less than 10 EINO_x at scaled climb-out power. In addition, smoke numbers were consistently below 5 SAE, although further optimization for idle blow-out stability and traverse quality is required.