Fuel injection apparatus

A fuel injection apparatus comprising:

• a fuel injector having a cylindrical housing, a tubular body centrally disposed within the cylindrical housing and spaced apart therefrom so as to define a first annular air passage therebetween, fuel swirl means disposed within the tubular body for imparting a swirl to an inlet stream of fuel wherein the interior surface of the tubular body converges to a minimum diameter orifice downstream from the swirl member, and thereafter diverges outwardly terminating in a transverse edge so as to generally define a venturi, and a primary air swirl means having a plurality of circumferentially spaced apart swirl vanes disposed intermediate the tubular body and cylindrical housing for swirling an inlet flow of air in the same direction as the fuel swirl;
• a generally cylindrical primary shroud coaxially spaced downstream from the fuel injector defining a central core air passage therethrough;
• secondary air swirl means disposed intermediate the injector and primary shroud to impart a circumferential swirl component to the flow through the core wherein the secondary swirl component is in the same circumferential direction as the fuel and primary air swirl;
• tertiary air swirl means disposed downstream of the secondary air swirl means to impart a circumferential swirl component in the direction opposing that of the secondary swirl means such that fuel reaching the downstream end of the primary shroud is atomized by the shear stresses developed by the counter-rotating aerodynamic forces at the confluence of the secondary and tertiary swirls;
• wherein
• the primary swirl means are disposed at the inlet to the first annular air passage, and the inner and outer surfaces of the first annular air passage converge conically inward to a minimum cross-sectional area and then diverge conically outward so as to define a second venturi coaxially disposed about the first venturi wherein the downstream edge of the cylindrical housing is coplanar to the downstream edge of the tubular body;
• the secondary air swirl means includes a second plurality of circumferentially spaced swirl vanes disposed intermediate a first radially extending circumferential wall member concentric to the fuel injector and a second axially spaced apart radially extending circumferential wall member connected to the primary shroud;
• the tertiary air swirl means includes a third plurality of circumferentially spaced swirl vanes disposed intermediate the second wall member and a third axially spaced apart radially extending circumferential wall member, and
• a mini cowling comprising an outer cylindrical wall in connection to the outer periphery of the second wall member and defining first and second annular plenums which respectively direct inlet airflows to the secondary and tertiary swirl means from an external source of pressurized air wherein the pressurized airflow entering each plenum is rapidly diffused in order to reduce the variation in pressure and velocity of the inlet airflow to the respective swirl vanes.

A fuel injection apparatus comprising:

• fuel injection means;
• a generally cylindrical primary shroud coaxially spaced downstream from the fuel injection means defining a central core air passage therethrough;
• primary air swirl means disposed intermediate the injector means and primary shroud to impart a circumferential swirl component to the flow through the core wherein the swirl means includes a first plurality of circumferentially spaced swirl vanes disposed intermediate a first radially extending circumferential wall member concentric to the fuel injection means and a second axially spaced apart radially extending circumferential wall member connected to the primary shroud;
• secondary air swirl means disposed downstream of the primary air swirl means to impart a circumferential swirl component in the direction opposing that of the primary swirl means such that fuel reaching the downstream end of the primary shroud is atomized by the shear stresses developed by the counter-rotating aerodynamic forces at the confluence of the primary and secondary swirls wherein the secondary swirl means include a second plurality of circumferentially spaced swirl vanes disposed intermediate the second wall member and a third axially spaced apart radially extending circumferential wall member;
• and a mini cowling having an outer cylindrical wall in connection to the outer periphery of the second wall member and defining first and second annular plenums which respectively direct inlet airflows to the secondary and tertiary swirl means from an external source of pressurized air wherein the pressurized airflow entering each plenum is rapidly diffused in order to reduce the variation in pressure and velocity of the inlet airflow to the respective swirl vanes.