Experimental Studies of the New Type Vaporizing Blue Flame Burner Applied to the Domestic Space Heater

Development of various vaporizing blue flame burners for home appli-ances has been continuing in Japan, Because of their clean and smoke free combustion and fast response for on-off operation.They are premixed-type burners whose combustion-spaces are separated from the vaporizing and premixing-spaces by a plate with a number of flame ports. These conventional vaporizing burners, however, operate with a very narrow firing range due to the flame port plates which prevent flame flashback from the combustion-space to the vaporizing and premixing-space. This paper discribes design consideration, construction and performance of a new vaporizing burner which has a wider firing range operation and blue flame combustion.The burner is a “can-type ”, -for heat input of 4500 Kcal / h-quite different from the“pot-type”and the conventional vaporizing burner. Test results have shown that: (1) by vaporizing fuel and mixing it with the high velocity air flow, about 10 m/s through a number of open-holes with 1 mm diameter on the liner, stable and smoke free combustion-a clean and blue flame-can be achieved. (2) by arranging the ratio of the annular air flow path AA to that of the liner AL, AA/AL >0.36, stable combustion can be maintained throughout the operating range, turn-down ratio 1/4-1/5, at the fixed air flow rate.