Fuel nozzle device comprising a swirler having spiral swirl vanes
A fuel nozzle device for a gas turbine engine includes a nozzle body extending in an axial direction and projecting into the combustion chamber, and swirler including a tubular portion concentrically surrounding the nozzle body, a deflector formed as a hollow shell concentrically surrounding the tubular portion, and a plurality of swirl vanes extending between the tubular portion and the deflector. Each swirl vane extends along a logarithmic spiral around an axial center of the nozzle body between the tubular portion and the deflector with a certain meridian crossing angle α and a certain twist angle Φ such that the outer peripheral inclination angle θ is smaller than the stacking angle β of the swirl vane when the swirl vane is manufactured by an additive manufacturing process with a front end up orientation.
1. A fuel nozzle device for injecting fuel into a combustion chamber of a gas turbine engine, comprising;
a nozzle body extending in an axial direction and projecting into the combustion chamber; and
a swirler including a tubular portion concentrically surrounding the nozzle body, a deflector formed as a hollow shell concentrically surrounding the tubular portion, and a plurality of swirl vanes extending between the tubular portion and the deflector, each swirl vane extending along a logarithmic spiral around an axial center of the nozzle body between the tubular portion and the deflector with a certain meridian crossing angle α and a certain twist angle Φ as measured from a leading edge to a trailing edge of the swirl vane such that an outer peripheral inclination angle θ as represented by θ=arctan (L/(rΦ)) is smaller than a stacking angle of the swirl vane as represented by β=arctan (L/(rΦ cos α)), where L is the chord length L of the swirl vane as measured in the axial direction, and r is the inner diameter of the central cylinder.
2. The fuel nozzle device according to claim 1 , wherein an annular space is defined between an outer periphery of the nozzle body and the tubular portion, and a plurality of additional swirl vanes extend between the nozzle body and the tubular portion, each additional swirl vane extending along a logarithmic spiral around an axial center of the nozzle body between the nozzle body and the tubular portion with a certain meridian crossing angle α and a certain twist angle Φ as measured from a leading edge to a trailing edge of the swirl vane such that an outer peripheral inclination angle θ as represented by θ=arctan (L/(rΦ)) is smaller than a stacking angle of the swirl vane as represented by β=arctan (L/(rΦ cos α)), where L is the chord length L of the swirl vane as measured in the axial direction, and r is the inner diameter of the central cylinder.
3. The fuel nozzle device according to claim 2 , wherein the logarithmic spiral of the additional swirl vanes extends circumferentially in an opposite direction to that of the swirl vanes.
4. A fuel nozzle device for injecting fuel into a combustion chamber of a gas turbine engine, comprising;
a nozzle body extending in an axial direction and projecting into the combustion chamber, the nozzle body having an annular configuration so as to include a central cylinder internally defining a central air flow passage; and
a swirler including a plurality of swirl vanes extending radially inward from the central cylinder,
each swirl vane extending along a logarithmic spiral around an axial center of the nozzle body with a certain meridian crossing angle α and a certain twist angle Φ as measured from a leading edge to a trailing edge of the swirl vane such that an outer peripheral inclination angle θ as represented by θ=arctan (L/(rΦ)) is smaller than a stacking angle of the swirl vane as represented by β=arctan (L/(rΦ cos α)), where L is the chord length L of the swirl vane as measured in the axial direction, and r is the inner diameter of the central cylinder.