To prevent the vibration in combustion at the time of a small quantity of fuel injection of a dual fuel nozzle.
A dual fuel nozzle 3 is provided with a first fuel injection port 4 large in diameter and a second fuel injection port 5 small in diameter. At use of gas fuel, in case that the quantity of injected fuel is large, fuel is jetted from first or second jet or both jets, and in case that the quantity of injected fuel is small, the fuel is injected from only the second jet 5 small in diameter. Furthermore, at use of liquid fuel, the fuel is injected from the second jet 5 in condition that the fuel is mixed with atomizing steam in advance. It becomes possible to maintain the differential pressure between jets enough high even in case that the quantities of injected fuel are both small, by changing the total area of the jets, according to the flow of fuel, at use of gas fuel, and jetting the mixture between the steam and the fuel and increasing the flow velocity at use of liquid fuel, so this can prevent vibration in combustion from occurring.
OOTA MASATOYO
KOBAYASHI KAZUYA
NISHIDA KOICHI
