Establishment time of liquid flow in a bath agitated by bottom gas injection

Iguchi, Manabu; Kondoh, Tsuneo; Nakajima, Keiji

doi:10.1007/s11663-997-0032-4

Cited by 12 publications

(8 citation statements)

References 20 publications

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“…2) • Accurate estimation of flow establishment times from Fig. 1 is difficult particularly for the higher gas flow rates.…”

Section: Present Work 21 Experimentalmentioning

confidence: 99%

“…Recently, however, some studies 2,3) were reported wherein transient flows during the initial period of gas bubbling were investigated experimentally in aqueous models of gas stirred ladle systems. In an earlier work, Iguchi et al 2) measured the flow establishment times (i.e., the duration over which flow is transient in the system) in an axisymmetric water model ladle (Lϭ300 mm and Dϭ200 mm) for various gas flow rates by monitoring velocity at two different locations in the bath through Laser Doppler Velocimetry. Their experimental results indicated that flow establishment times are typically small, of the order of 60 s and varies as (gas flow rate) Ϫ0.5 .…”

Section: Introductionmentioning

confidence: 99%

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Transient Flows in Gas Stirred Vessels during Initial and Post Gas Injection Periods.

Mazumdar

Seybert²,

Steingart³

2003

ISIJ International

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“…2) • Accurate estimation of flow establishment times from Fig. 1 is difficult particularly for the higher gas flow rates.…”

Section: Present Work 21 Experimentalmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Transient Flows in Gas Stirred Vessels during Initial and Post Gas Injection Periods.

Mazumdar

Seybert²,

Steingart³

2003

ISIJ International

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“…[1][2][3][4][5][6][7] Top blowing has also been covered in a number of texts. 5,6,[8][9][10] Combined top and bottom blowing has been discussed by for instance Diaz-Cruz et al 5) and Koria.…”

Section: Introductionmentioning

confidence: 99%

“…4) Iguchi et al also investigated the establishment time of the bath during bottom blowing, as well as the bubble characteristics when the system was under low pressure. 2,3) Bradshaw and Wakelin gave a relationship for the penetration depth on a bath surface caused by an impinging gas jet. 8) Nordqvist et al investigated the swirl motion in a bath induced by an impinging jet.…”

Section: Introductionmentioning

confidence: 99%

Fluid Flow in a Combined Top and Bottom Blown Reactor

et al. 2006

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Physical modeling was done to study the flow field in a cylindrical bath agitated by bottom purging, top lance blowing and a combination of both injection types. A particle image velocimetry (PIV) system has been used to capture the velocity field of all three cases mentioned above. Special attention was paid to the recirculation loop. Top blowing creates a re-circulation loop in a relatively small volume close to the surface, compared to bottom-and combined-blowing. Increasing bottom flow rate moves the center of the re-circulation loop downwards into the liquid. When top blowing is combined with bottom blowing the center of the re-circulation loop is moved downwards into the liquid with increasing top lance flow rate.KEY WORDS: fluid flow; reactor; bottom purging; lance blowing.ISIJ International, Vol. 46 (2006), No. 8, pp. 1137No. 8, pp. -1142 was set to 50 mm above the undisturbed bath surface. Also, when used, the bottom nozzle (f2 mm) was placed in line with the center axis of the cylinder. The tracer substance used was a polymer from MCI GEL ® with model name CHP2OP. It has a density of 1.03 g/cm 3 and a diameter distribution of 75-150 mm. Before the tracer particles were added to the de-ionized water, they were subjected to Ethanol in order to remove trapped air inside the particles. This is important since trapped air causes unwanted buoyancy. Before each experiment there was a short time to let the flow field stabilize, this time was small, usually less than 5 min.Three cases have been studied: 1. Top blowing 2. Bottom blowing 3. Combined top-and bottom blowing Each case has a number of conditions set, which can be seen in Table 1. Equations UsedCylindrical coordinates are used in order to describe the system, where u, v and w are the velocity components in the radial, azimuthal and axial (r, q, z) directions respectively. Only the axial and the radial velocity components were registered in the experiments. The mean velocities; U, W are calculated as follows: where N corresponds to the number of data samples. ResultsSince the bubbling jet affects the laser the readings on the left side of the axis are less accurate (see Fig. 1 for the setup). Accordingly, the right side of the flow field has been the main viewpoint. The flow field in the bath can be classified as having a number of regions i.e., the momentum-, the transition-, the buoyancy-and the surface-region as well as the re-circulation region.7) The first four regions describe the bubbling jet and the re-circulation region is outside the bubbling jet. Figure 2 shows a vector plot of the mean velocity in a two-dimensional plane where the symmetry plane is to the left and the vessel wall to the right, which is the same for all figures. Data are presented for a case when only bottom purging through a centrally placed nozzle was used and for the following gas flow rates, Vol. 46 (2006) 49.5 cm 3 /s and (c) 92.0 cm 3 /s. As can be seen the water is lifted up towards the surface due to buoyancy forces resulting from the gas that is injected. Therea...

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“…Figure 2-12 Experimental apparatus in Iguchi's research [45][46][47][48] Figure 2-13 Conductivity electrode in Iguchi's research [45][46][47][48] In order to study fluid flow phenomena in liquids of varying kinematic viscosities, Iguchi built up another physical model [49][50][51] . Transparent oily liquids such as silicone oil were usually used to simulate slag.…”

Section: Sinha and Mcnallanmentioning

confidence: 99%

Fluid dynamics studies related to bottom blown copper smelting furnace

Shui¹

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The bottom blown copper smelting furnace is a novel technology developed by Dongying Fangyuan Nonferrous Metals Co. Ltd. China. Since it started in 2008, many advantages have been reported from industrial practice, such as high volume specific smelting capacity, low copper loss, autogenous smelting, adaptive to feeds, low temperature operation and so on. Most of those features are relevant to the fluid dynamics of the molten bath in the furnace. However, the detailed behaviour of molten bath in the bottom blown reactor still is not comprehensively understood.To understand the behaviour of molten bath in this newly established furnace, a 1/12 lab scale cold model was constructed according to the principles of similarity. In this physical model, water was used to simulate the liquid matte, compressed air was used to simulate oxygen enriched air blowing and its flowrate was adjusted accordingly. Silicone oils with different viscosities were used to simulate the molten slag layer of various viscosities. In the present study, several features of the bottom blown bath behaviour were investigated by using this physical model. In addition to single phase mixing behaviour study, multiphase bath mixing behaviour was also studied to further investigate the mass transfer in the presence of top layer. Single lance blowing was used and experimental variables including water height, gas flowrate, oil layer height and oil 2 viscosity were adjusted to investigate the impact of each on mixing. It was found that the mixing time decreases with water height and gas flowrate in a greater rate than that of single phase system, while it is increasing with oil layer height and oil viscosity, where the rate with oil layer height is much greater. An overall empirical relationship with these variables was developed as following, and it showed a good prediction of mixing time under different conditions.The correlation was then generalised to a model-independent format for wider use:Three different types of surface waves were studied in the single phase bath with single lance blowing. The 1 st asymmetric standing wave was found the most significant type among the three because it leads the entire bath to swing laterally. The 1 st asymmetric standing wave was found to take place only at certain combination of bath height and gas flowrate, which is summarised in two sub-boundaries in terms of bath depth, gas flowrate and blowing lance angle.Sub-boundary 1 = 0.036. .Sub-boundary 2 = 0.63. .The measured amplitudes at several conditions show that tapping end amplitude increases with flowrate and bath height, and when the 1 st symmetric standing wave is taking place, the amplitude is remarkably increased. The frequency of the 1 st asymmetric standing wave does not change with flowrate or blowing angle, but slightly increases with bath height.The longitudinal wave exists on bath surface when the combination of bath height and gas flowrate is out of the critical occurrence boundary. To study the behaviour of the longitudinal wave, the model ...

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Establishment time of liquid flow in a bath agitated by bottom gas injection

Cited by 12 publications

References 20 publications

Transient Flows in Gas Stirred Vessels during Initial and Post Gas Injection Periods.

Transient Flows in Gas Stirred Vessels during Initial and Post Gas Injection Periods.

Fluid Flow in a Combined Top and Bottom Blown Reactor

Fluid dynamics studies related to bottom blown copper smelting furnace

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