キュポラ予熱帯における地金の熱吸収におよぼす装入地金の形状とその構成状況の影響

抄録

  The authors analyzed the heat transfer phenomena in the preheat zone of cupola by using a model. In this paper, effects of shape and charge material composition on the melting efficiency are described. To model a condition similar to the cupola operation, steel of spherical, cylindrical and rectangular shapes was used as charge material for comparing the difference in the heat absorption behavior. In another series, graphite was used together with steel ball to simulate a coexisting condition. Heat absorption behavior was examined by blowing hot gas into the packed bed. When changing the shape of steel, with surface area kept constant, heat accumulation was faster with increasing specific surface area as expected. Further, when the specific surface area and the heat receiving area of the packed bed were kept nearly constant, heat absorption was almost the same, independent of the charge shape. This fact can be used as a basis for determining the optimal cupola charge.
  To study the influence of charge composition in the preheat zone, graphite was placed near the bottom and steel balls near the top. Heat accumulation of graphite was fast due to its higher heat conductivity and lower heat capacity, resulting in a higher heat absorption rate by the steel. Heat absorption rate was lower, when steel balls and graphite were uniformly mixed. The results of this model indicate that a “layer by layer ” charging is effective for obtaining a high melting efficiency in cupola melting.