Hydrodynamic Study on the Separation of Inclusion from Liquid Metal
Grant-in-Aid for Scientific Research (C).
|Research Institution||TOHOKU UNIVERSITY|
谷口 尚司 東北大学, 工学部, 助教授 (00111253)
KIKUCHI Atsushi Tohoku Univ., Faculty of Eng., Professor, 工学部, 教授 (00005307)
|Project Fiscal Year
1990 – 1991
Completed(Fiscal Year 1991)
|Budget Amount *help
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1991 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1990 : ¥1,700,000 (Direct Cost : ¥1,700,000)
|Keywords||Nonmetallic Inclusion / Particle Migration / Lift Force / Inclusion Separation / Clean Steel / Turbulent Coagulation / Dispersion Force / Hamaker Constant / 非金属介在物 / 粒子泳動 / 揚力理論 / 介在物除去 / 高清浄鋼 / 乱流凝集 / 分散力 / ハマーカー定数 / 溶融金属 / 介在物 / 粒子の泳動 / 壁付着 / レイノルズ数 / 無次元相関式 / 凝集速度 / 急凝集 / 粒子の壁付着 / モデル実験 / 粒径分布|
Separation of nonmetallic inclusion from liquid metal is very important for getting clean materials which is desired in recent years. The purpose of this study is to get fundamental knowledge on the hydrodynamic behavior of inclusion particles in liquid metal. The following two model experiments have been made.
1. Lateral migration of hollow glass spheres in vertical pipe flows of water
Hollow glass spheres, 55-135mum in diameter, were injected in a vertical pipe flow of water or aqueous glycerol solution, and the collection efficiencies of particles on the wall, eta, was measured at the exit of the pipe. The following results were obtained;
(1) In the case of the upward flows, the value of eta increased with increasing the length of the pipe, and it changed with the liquid velocity, the particle diameter, the viscosity of liquid and the pipe diameter. The value of eta decreased rapidly in the region of Re>5000, Where Re is the tube Reynolds number.
(2) In the case of the downward flows, p
articles tended to depart from the pipe wall and dispersed homogeneously at the high Reynolds numbers.
(3) The values of eta calculated from various lift force theories by using the trajectory theory did not agree with the observed results.
(4) Rubinow and Keller's equation on migration velocity of a rotating sphere in a uniform shear flow was modified by multiplying a correction factor, beta, and then values of eta were calculated. Comparing the calculated and observed values of eta, the values of bata were determined and correlated with the particle Reynolds number and the tube Reynolds number.
(5) By using this correlation, values of eta of alumina particles in liquid steel were estimated for various conditions.
2. Coagulation rate of fine particles in a stirred vessel
The turbulent coagulation rates of polystyrene-latex particles (PSL, 2.85mum) and alumina particles (1.8, 4.85mum) in aqueous electrolyte solutions were measured in a stirred vessel. The following results were obtained;
(1) The coagulation rates of the PSL particles in the rapid coagulation condition were consistent with the calculated values by the previous coagulation theory.
(2) The coagulation rates of alumina particles were measured at various pH values and electrolyte concentrations to find a rapid coagulation condition. This condition was found to be at pH=8 and C(NaCl)>0.1mol/1.
(3) The coagulation rates of alumina particles (1.8mum) agreed with the calculated values by the previous theory. For larger alumina particles (4.85mum), breakup and sedimentation of agglomerates were observed in the later stage of coagulation. Less
Research Output (9results)