| 摘要 |
PURPOSE:To reduce a discharge rate of thermal NOx generated mainly in a high temperature area by providing a double structure burner throat for mixing fuel injected from an injection nozzle with burning air, and absorbing exhaust gas after heat exchange through a heater tube in the burner throat. CONSTITUTION:In an external combustion engine, fuel such as gas or lump oil is burned in a burner, heat of combustion gas after heating high temperature expanded space by means of a heater tube 13 is recovered by an air pre-heater 17. A burner throat 16 for mixing the fuel injected from an injection nozzle 14 with burning air has a double structure. A part of low temperature combustion gas which is heat exchanged by the heater tube 13 is suctioned inside the burner throat 16. Namely, combustion gas re-circulation effect is provided, and a discharge rate of thermal NOx generated in a high temperature area is reduced by lowering combustion frame temperature. Oxidising of the burner throat 16 caused by frame is suppressed through one kind of film cooling effect. |
