The invention relates to a fuel injection system for a combustion chamber of a gas turbine engine having improved homogenization of the air/fuel mixture.
Gas turbines in aeronautical applications must undergo a wide range of operating conditions and must meet increasingly demanding performance criteria. To achieve such demands requires increasingly difficult trade-offs. Typically such a difficult tradeoff arises by attempts to maintain flame stability under low power operating conditions and the conflicting need to avoid smoke and nitrogen oxides emissions under full power operating conditions. The fuel and air injection system for todays engines must ensure proper combustion under all of the widely varying operating conditions. The only way to achieve these desired operating parameters is to obtain optimal homogenization of the fuel/air mixture while at the same time maintaining an even radial temperature profile at the outlet of the combustion chamber in order to avoid inducing undesirable thermal stresses in the turbine wheels.
French Patent 2 596 102 illustrates, in FIG. 18, a mechanical system for a fuel injector wherein an swirler has a number of ribs bounding an equal number of air intake passages. Alternate ones of the air intake passages form a radial air intake to direct a flow of air around the fuel injection duct to form a first mixture in the combustion chamber bounded by a member having an inner converging-diverging contour. The alternate air passages form axial intakes to direct a flow of air into the rearward periphery of the housing. While generally successful, this structure of the alternating air feed passages restricts the permeability of the pre-mixing swirler.