Patent ID: 8468832

Claim:
A combustor comprising: a fuel nozzle for jetting out a hydrogen-containing fuel into a combustion chamber formed at a downstream side; an air hole plate of a flat-plate shape disposed between the fuel nozzle and the chamber, the air hole plate facing an upstream side of the chamber; a plurality of air holes provided in the air hole plate, which are inclined in a circumferential direction relative to a central axis of the air hole plate, such that a fuel flow and an air flow formed at an outer circumferential side of the fuel flow are blown out into the chamber from the respective air holes; the plurality of air holes are disposed in a plurality of rows on the air hole plate in a radial direction relative to the central axis of the air hole plate; wherein a clearance defined between any two circumferentially adjacent air hole inlets provided on a face of the air hole plate that is nearer to the fuel nozzle is formed wider than a clearance defined between any two circumferentially adjacent air hole outlets formed on a face of the air hole plate that is nearer to the chamber; the plurality of rows each having circumferentially inclined holes to form a swirling flow in the combustion chamber; the swirling flow forming a stagnation point within the combustor along a central axis of the combustor and a recirculation flow downstream of the stagnation point; and when a number of air holes is taken as N (N is more than four), a thickness of the air hole plate, as “t”, a diameter of the air holes, as D 2 , the clearance between any two air hole outlets on the air hole plate face nearer to the chamber, as “a”, the clearance between any two air hole inlets provided on the air hole plate face nearer to the fuel nozzle, as “b”, and a swirling angle imparted to the air holes, as “θ”, the relationship shown in the following formulas (1) to (3) are satisfied: N > 1 0.615 ⁢ ( D ⁢ ⁢ 2 t ) + 0.594 ⁢ ( a t ) ( Formula ⁢ ⁢ 1 ) 1 { 0.786 ⁢ ( a t ) 5 - 2.46 ⁢ ( a t ) 4 + 2.98 ⁢ ( a t ) 3 - 1.79 ⁢ ( a t ) 2 + 0.581 ⁢ ( a t ) + 0.0115 } ⁢ N × a < 1 b ⁢ ⁢ 1 b < 1 { 0.105 ⁢ ( a t ) 3 - 0.247 ⁢ ( a t ) 2 + 0.226 ⁢ ( a t ) + 0.00215 } ⁢ ⁢ N × a ( Formula ⁢ ⁢ 2 ) θ < sin - 1 ⁡ [ { - 0.232 ⁢ ( a t ) + 0.156 } ⁢ ( D ⁢ ⁢ 2 t ) ⁢ N + 0.165 ⁢ ( a t ) ⁢ N ] . ( Formula ⁢ ⁢ 3 )