By installing a cylinder 53 x having a bell-mouth construction to the downstream side of a combustor basket 2 a and by providing different level to the downstream-side end of the cylinder 53 x , notches 60 are constructed. The notches 60 form fixed vortices in the compressed air, and the vortices enable the compressed air to determine the flow direction thereof so as to flow toward the tips of the main nozzles 22.
1. A combustor comprising:
a pilot nozzle provided at a center of an axis of the combustor, and performing diffusion combustion;
main nozzles provided circumferentially around the pilot nozzle so as to be equally spaced with each other, and performing premixed combustion;
a combustor basket covering outside circumferences of the pilot nozzle and the main nozzles;
a cylinder connected to a first distal end, on first proximal sides of the main nozzles, of the combustor basket,
having an expanding outside wall which is formed from first distal sides of the main nozzles to the first proximal sides of the main nozzles, and
having a second distal end, on the first proximal sides of the main nozzles, which is formed in a semicircular cross-sectional shape;
an external cylinder provided around an outside circumference of the combustor basket and the cylinder so as to form a passageway of a compressed air between an inside wall thereof and an outside wall of the combustor basket and the expanding outside wall of the cylinder; and
notches each of which is formed at tips on the second distal end of the cylinder by providing a slot which forms a step, at a position corresponding to a radial line connecting an intermediate position of an adjacent pair of the main nozzles and a center axis of the combustor, wherein
the notches are grooves which are indented with respect to the other surfaces of the second distal end.
2. The combustor according to claim 1 ,
wherein, the notches are formed from tips on a side of bases of the main nozzles of the cylinder toward inside wall of the cylinder so as to go around.
3. The combustor according to claim 2 ,
the notches are continuously formed from the expanding outside wall of the cylinder toward the inside wall of the cylinder.
4. The combustor according to claim 3 ,
wherein the notches are formed so as to spread toward the second distal end of the cylinder.
5. A combustor comprising:
a pilot nozzle provided at a center of an axis of the combustor, and performing diffusion combustion;
main nozzles provided circumferentially around the pilot nozzle so as to be equally spaced with each other, and performing premixed combustion;
a combustor basket covering outside circumferences of the pilot nozzle and the main nozzles;
a cylinder
connected to a first distal end, on first proximal sides of the main nozzles, of the combustor basket,
having an expanding outside wall which is formed from first distal sides of the main nozzles to the first proximal sides of the main nozzles, and
having a second distal end, on the first proximal sides of the main nozzles, which is formed in a semicircular cross-sectional shape;
an external cylinder provided around an outside circumference of the combustor basket and the cylinder so as to form a passageway of a compressed air between an inside wall thereof and an outside wall of the combustor basket and the expanding outside wall of the cylinder; and
notches each of which is formed in the second distal end of the cylinder by providing a slot which forms a step, at a position corresponding to an intermediate position between an adjacent pair of the main nozzles, wherein
the notches are continuously formed from the expanding outside wall of the cylinder via the second distal end toward an inside wall of the cylinder.