【摘要】 用水模型对顶吹、中心小流量底吹及复合吹,在不同的气体流量下,用铝粉示踪法研究了熔池内的流谱,用频闪光照像法测定了涡环中的速度分布并由此计算循环流量.循环流量(Q_c)与顶吹流量(Q_T)和底吹流量(Q_B)间的关系为:Q_c=O.659Q_T+5.175Q_B-0.051 (Q_T)~2-4. 975(Q_B)~2-O.229Q_TQ_B.在试验的参数范围内,循环流量与顶吹气体流量之间为具有一极大值的曲线,循环流量与底吹气体流量之间为一条逐渐变缓的上升曲线,复合吹的循环流量小于单纯顶吹和底吹时的代数和,附加底吹所增加的循环流量随顶吹量的增大而减小.更多还原

【Abstract】 Using hydraulic model, the flow of the baths of the top, the bottom (central with small flow rates) and the top and bottom blowings with various gases flow rates have been studied. The visualization of the flow pattern is carried out by using aluminium powder as tracer. The flow fields of the baths in those conditions are regarded as two-dimensional axisymmetrical in which vortex rings are formed. The dimensionless coordinates of the vortex rings are that Z_o/H=0.57 and 2R_o/D=0.83. From the velocity fields, estimated according to pictures taken with a stroboscope, the recirculating flow rates have been calculated. A formula has been developed to describe the relation between the recirculating flow rate, Qc, and the gas flow rates of the top and the bottom blowings, Q_T and Q_B, which is as follow:Q_c=0.659Q_T+5.175Q_B-0.051Q_T~2-4.975Q~2_B-0.229Q_TQ_BAt the top blowing, the curve representing the Q_c and Q_T is the one with a maximum value, while in the condition of bottom blowing the curve for Q_c and Q_B is an ascending one with gradually decreasing gradient. The recirculating flow rate with both top and bottom blowings is less than the sum of those of the top and the bottom blowings separatly. The recirculating flow rates increased due to supplementary bottom blowing are decreased with increasing flow rates of top blowing.更多还原