LEAN PREMIXED COMBUSTOR AND COMBUSTION METHOD

PROBLEM TO BE SOLVED: To ensure combustion stability of a combustor for burning gas or liquid fuel as main fuel and to reduce the amount of NOx emission. SOLUTION: The combustor comprises at least one injection hole 5 for injecting a mixture 4 in a circumferential direction of a combustion cylinder 7 to form a flame flowing along the circumferential direction and to allow combustion gas to form swirling flow or return flow which joins an unburnt mixture jet immediately after injection. Combustion gas including active chemical species of high temperature with advanced combustion reaction is mixed into the unburnt mixture immediately after injection, and the combustion gas including active chemical species of high temperature with advanced combustion reaction is mixed into an unburnt fuel/air mixture to attain high temperature of the lean mixture. A combustible range is thereby enlarged to stabilize combustion. After sufficient progress of oxidation of carbon monoxide in an oxidation process of hydrocarbon fuel in the flame, air for freezing reaction is injected to freeze reaction of producing Zeldovich NO, or fuel or a mixture in excessive fuel conditions is injected to reduce Prompt NO produced in combustion gas to thereby achieve low NOx combustion. COPYRIGHT: (C)2007,JPO&INPIT