ISIJ International, Vol. 33 (1 993). No. 7, pp. 740-747 Mixing Phenomena in a Liquid Side and Inclined Nozzles Bath Stirred by Gas Jets through Sergey V. KOMAROV. Kenji ITOH.1) Masamichi SAN02) and Konstantin A. BLINOV3) Formerly Department of Materials Processing Engineering, Nagoya University. Now at Russia. Moscow, Steel and Institute. Leninskiy Avenue, Moscow, Russia. 1 ) Formerly Graduate School, Nagoya University. Now at Kobe Ltd., Nadahamahigashi-cho, Nada-ku. Kobe. Hyogo-ken, 657 Japan. 2) Department of Materials Processing neering. Faculty of Engineering, NagoyaUniversity, Furo-cho, Chikusa-ku, Nagoya, Aichi-ken, 461 -OI Japan. 3) A. A. Baykov Institute of Metallurgy, Russia Academy of Sciences, Leninskiy Avenue, Moscow.Russia. (Received on December 2. 1992.• accepted in final form on March l9. 1993) Alloys Steel, Engi- The perfect mixing time, t~, of the water bath, during gas injection through bottom (vertical and iclined) and side nozzles has been measured by using electrical conductivity technique. Effects of gas flow rate, bath depth, nozzle angle and location have been examined. The measurements indicate that under the condition of a shallow bath (H/D =0.31 ) and large gas flow rate (specific power e> I O-' W/kg) influences of the nozzle angle and nozzle location on the mixing time are significant, On the other hand, effects of those parameters on t~ are negligible in a deep bath (HID=1 ,25). Change in the tracer concentration with time was predicted by numerical modelling. A satisfactory agreement between the computed and experimental results can be obtained by parameter fitting for the average plume rise velocity and effective viscosity in the mathematical model. It is presumedthat turbulent mass transfer of the tracer is dominant in the deep bath, whi]e the convection of liquid is more effective in the homogenization in the sha]low bath. KEYWORDS: perfect mixing time; cold model; side and inclined injection; numerical modelling; turbulent mass transfer; convection. 1. Introduction Mass transfer phenomena in metallurgical processes are largely governed by hydrodynamical characteristics of a melt bath. In essence, hydrodynamics together with surface phenomenahas a dominant effect on the refining rate in the processes. Therefore, our under- standing of hydrodynamical phenomena is very impor- tant to solve many practical problems. Recently, new metallurgical processes have been developed to refine metal in a liquid state by means of gas injection. These processes have found application both at the pretreatment and at the ladle treatment stages. The injection produces circulation and agitation in the bath, which are mainly connected with two effects - convection and turbulent diffusion. It is well known that the mixing intensity depends on a gas flow rate.1'3) Besides tuyere location at the bottom, bath depth also has an effect. Many studies on the mixing phenomenahave been carried out by using numerical modelling.4'5) It is found that fluid fiow velocity and turbulence energy distributions in the stirred bath are nonuniform. This leads to the appearance of tempera- ture and concentration distributions in the bath. These results have been confirmed by experiments.6) The purpose of the present work is to study the mixing phenomena in a gas stirred liquid bath. The liquid bath is stirred by inclined gas injection at the bottom or side gas blowing. The effects of direction of gas fiow and tuyere location on mixing time are studied. A numerical calculation is madeto clarify the dispersion characteristics of added tracer. 2. Experimental The experimental madeof acrylic resin set is shown in Fig. 1. The vessel has an inner diameter of 480 mm 9) ~~ 1) I 2 8) V 7) 3) 6) 5) 4 1) 1) Gas cylinder 2) F[ow meter 3) Water 5) Conductivity meter 4) Probe 6) Referen~ voltage vnit 7) Amp[ifier 8) Computer 9) Super computer Fig. l. Experimental apparatus. bath @ 1993 ISIJ 740