SynopsisMeasurements were made of the total holdup, gas pressure drop and flooding velocities for flow through packed beds at low superficial velocities of liquid for various degrees of wetting between the liquids and solids.Correlations for both static and dynamic holdup, and a flooding diagram which is valid for non-wetting as well as wetting flow, were obtained.An instability of the bed, in which a transition from a stable to a fluidiced bed occurred, was observed before the onset of flooding in some experiments. A diagram was developed to differentiate f luidisation from hooding in relation to the flow conditions. The diagram indicates that, in blast , furnaces, fluidisation of the coke bed is likely to start before the onset of flooding by the slag. The abnormal flow phenomena which could occur in the furnace are discussed in terms of the fluidisation of the coke bed in the dropping zone.

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I n order to clarifY the causes of the excess accumulation of mollen materials in the blast furnace hearth which gives rise to a trouble in the blast furna ce operation , such as hanging and slillping, the behaviour of .flowing out and accumulating of slag in the hearth have been studied by m~ans of model eXlleriments. The results of th~ model experiments were analyz ed as the scale-up problem based on the th~ories of .fluid dynamics. The in.fluential fa ctors such as the porosity 0, the shape fac tor

The resuUs of lhe model experiments about the slag flow in the blast furnace hearth') have been combined with the slag balance in lhe hearth to give an equal ion which relates the slag tapping conditions to each other. The following results were oblained by using lhe equal ion for the simulalion of the slag tapping operalion as well as for the analpes of operational dala: (1) The calculaled amount of slag lapped agreed well with lhat observed. (2) An increase in lhe calculated amount of residual slag caused the blaslfurnace hanging morefrequentLy. (3) The residual amounl of slag and the depth of slag layer at the beginning of ils flow-out increased wilh lhe increase in lhe rale of slag tapping and in lhe viscosity of slag. (4) The increase in the number of lapping operations was beneficial 10 reduce the de/Jtlt of slag layer.