150t RH装置内钢液的流动和混合特性及吹气管直径的影响

FLOW AND MIXING CHARACTERISTICS OF MOLTEN STEEL IN A 150t RH DEGASSER AND INFLUENCE OF GAS INJECTION PORT DIAMETER

在几何相似比为1∶4的水模型上研究了150tRH装置内钢液的流动和混合特性及吹气管直径的影响。模型的吹气管内径分别为0.10、0.15和0.2cm。所得结果表明,该装置的环流量计算式为：Qlp=0.0291Qg0.323Du0.65Dd0.84（t/min）,式中Qg—提升气体流量,Nl/min;Du和Dd—上升管和下降管内径,cm。在给定的Qg、Du和Dd下,吹气管直径din的变化对液体的流态没有显著影响,环流量则略有改变,在（0.40~0.80）cm的范围内,Qlp=0.0304Qg0.322Du0.651Dd0.839din0.07。在Du和Dd均为53cm、din为0.60cm的情况下,该装置内钢液的最大（“饱和”）环流量约为135.1t/min,相应的Qg为2500Nl/min。钢包内钢液的混合效果随Qg的增大迅速提高。增大din使混合时间τm（s）略有缩短,对应于0.10,0.15和0.20cm的孔径,τm与搅拌功率密度ε（W/t）的关系分别为：τm∞ε-0.497,τm∞ε-0.493和Tm∞ε-0.476。

The flow and mixing characteristics of molten steel in a 150 t RH degasser and the influence of gas injection port diameter （din） were investigated on a water model unit with a geometry similarity ratio of 1/4. Three sets of the inner diameters of gas injection port with 0.10, 0.15 and 0.20 cm were used respectively. The results indicated that the circulation rate of molten steel in the RH degassermight be estimated with the following expression： Qtp = 0.0291Qg0.323 Du0.65 Dd0.84 （t/min）, where Qg-the lifting gas flow rate, Nl/min; Do and Da-the up-and down-snorkel inner diameter, cm, separately. At a given Qg, Do and Dd, the change in din. had evidently not influenced the flow characteristics of liquid, but Qlp varied slightly： Qlp = 0.0304Qg0.3220.651Dd0.839 0.07 Du 0.651Dd0.839d in0.07（t/min） （din= 0.40-0.80 cm）. In the case of Du and Dd either of 53 cm and din of 0.60 cm, the maximum （the ＂saturated＂） circulation rate for the degasser was approximately 135.1 t/min. The corresponding Qg was 2500 Nl/min. The mixing effectiveness of liquid in the ladle was rapidly enhanced with an increase in Qg ; and the mixing time τm （s） was slightly shortened with increasing of din. The relation between τm and stirring power density ε （W/t） in the degasser was obtained as： τm ∞ ε-0.497, τm∞ ε-0.493 and τm∞ ε-0476 , respectively for din of 0.10, 0.15, 0.20 cm.