An investigation of bubble plume mixing by comparison with liquid jet mixing.

Abstract

Mixing of liquids in tanks by means of a non-reacting gas-bubble plume was studied by using a tracer response method. The circulation time was obtained from the period of a damping oscillation of the response curve. The mixing time was defined as the time required to reduce the concentration variation to within 1%of the mixed mean value and was measuredby an impulse response. The results indicate that the induced liquid flow-rate varies as the first power of the submergence depth of the nozzle and as the 1/3 power of both the gas flow rate and the horizontal cross-section of the tank. When the circulating flow in the tank dominates the mixing, the ratio of mixing time to circulation time is nearly equal to that of the liquid jet mixing, and increases with decreasing distance between nozzle and side wall of the tank. Whengas is injected in a central region of the tank, the mixing time becomes larger with decreasing depth of liquid, due to an effect of relative stagnation. Rapid mixing is achieved by injecting gas at a mid-radius of the tank, where the effects of both tank wall and relative stagnation can be excluded.

Sediment Evacuation from Reservoirs through Intakes by Jet-Induced Flow

“…Okita and Oyama (1963), cited in Maruyama et al (1982), describe the mixing time as a function of the jet Reynolds number and as the jet Froude number. Maruyama et al (1984) as well as Zughbi (2006) found that the jet location had a major influence on jet mixing. Fox and Gex (1956) as well as Zughbi and Rakib (2004) reported that the jet angle and the jet length influence mixing time.…”

Mass Transfer Into a Free Liquid Surface Effected by Submerged Jets

“…Furthermore, the residence time distribution in the vessel is similar to that in a perfectly mixed vessel,deviations from it being dependent on the particular geometry of the vessel. Recent papers of Lane and Rice(1982)and Maruyama et al (1982Maruyama et al ( , 1984provided some relationships which can be used to calculate the mixing time in vessels in which liquid is mixed by turbulent jets. In the case of the smaller vessel (T= 0.2 m) the mixing times calculated from these relationships varied from 15 to 60s for the range of the flow parameters used in determination of the mass transfer coefficients.…”

Model Studies of Mixing Phenomena in Stirred Melts

“…Thus, the diameter to depth ratio nozzle, immersion depth of a lance, bath depth, and diameter to was 1.1, a value that is representative of a typical steel ladle. depth ratio [33][34][35][36][37][38]40]. In some studies, mixing experiments Nozzles enabling the introduction of various stirring gases were with various tracer input locations and positions of the meas-embedded in the bottom at a number of locations.…”

“…In some studies, mixing experiments Nozzles enabling the introduction of various stirring gases were with various tracer input locations and positions of the meas-embedded in the bottom at a number of locations. The tracer uring probe were also carried out [30,35,36]. used in this study was an aqueous sodium hydroxide solution.…”

“…well as from full scale measurements in a steel ladle show One involved the simultaneous measurement of the electrical damped oscillations caused by a recirculating flow in the vessel conductivity of the water at three different locations within the as well as a gradual increase in concentration during injection vessel. Each measurement thus gave the localized concentration [3,4,[25][26][27][28][32][33][34][35][36].…”