钢包中心透气砖吹氩时最佳吹气量研究

STUDY ON THE OPTIMAL FLOWRATE OF BOTTOMBLOWN ARGON THROUGH THE PERVIOUS BRICK IN THE LADLE CENTER

本文对钢包中心透气砖吹氩时最佳吹气量进行了研究。中心底吹氩气吹气量与中心线速度的三次幂成正比,与两相区圆锥角,钢液深度等因素有关。本文推导的公式与实验基本吻合。

The optimal flowrate of bottom-blown argon through the pervi- ous brick in the ladle center is researched in this work.The results have proven that the optimal flowrate is proportional to the third power of the central velocity,and is related to the cone angle of two-phase flow region, depth of steel liquid,and etc.The optimal flowrate equation is as follows: V_g=U_m^2(z+H_0)~2·[1n((Z~*)/(Z~*-Z))]^(-1)·[2πC^4(1-)ρ_1(298/(T_1)P_(atm)^(-1))] (tgθ/2)^(-2)·[1-exp(-1/(2C^2)tg^2θ/2)]·[(1-exp(-1/(C_2)tg^2θ/2)] In this equation,the central velocity U_m,is a variable,nowever literatures [2][3][4]assume that U_m is constant.But the predicted and experimental- ly measured results prove that U_m is not constant. The equations for central velocity U_m,average velocity U_z of two-phase flow region in the ladle and its hydrodynamic modle are deduced in this paper.All the equations derived are corresponded with experimental results. V_g,U_m,H,and θ are the main factors that influence the optimal flowrate. U_m,the central velocity,is the most important boundary condition of mathe- matical models,and is also an important parameter used in calculating the circulative flowrate,circulative period,time needed by mixing substances, and drawing ratio in the ladle.The central velocity equation is as follows: U_m=C_(2j)·H_(2j)· V_g^(1/3) Another form of the optimal flowrate equation is 3V_g=K_2h_d^(3/2) Where h_d denotes the protruding height from the surface of the two-phase flow region in the ladle center.And h_d=(U_2~2)/(2g),where ,denotes the average velocity of two-phase flow region.It can be written as follows: -U_m·2C^2(tgθ/2)^(-2)·[1-exp(-1/(2C^2)tg^2θ/2)]