Abstract
The wooden models of actual open hearth furnace having the various forms of ports were made about one tenth in their sizes. Therein air was introduced by a fan laid on their outlet sides, where a negative pressure was held up to 4mm. in water column. The velocity of flow in the various ports of models was measured carefully by means of Pitot tube with Askama minimeter. The observed value ranged from only 1m. to 6m. per sec. near the ports and variations in the speed of air flow in the inner ports were noted, showing some remarkable behaviours near the point of mixing.
To study the manner of the flow of gas and air, some small amounts of fine aluminium powder were blown in separately to the gas and air risers. With the aid of an electric arc light lamp, the flowing powders were photographised instanteneously.
From the close study of these experiments, it appears that the smallar size of air port than that usually designed in this country works better to mix well air with gas flow and to direct the mixture towards the face of steel bath. With the model of Maerz type, the velocties of gas and air, especially the mutual distance of gas and air ports should be taken in consideration to perform the suitable operation.
