Power Consumption in Mechanically Agitated Contactors Using Pitched Bladed Turbine Impellers

Rewatkar, V. B.; Rao, K. Sankara; Joshi, Jyeshtharaj B.

doi:10.1080/00986449008940548

Cited by 43 publications

(26 citation statements)

References 9 publications

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“…In general, the Ne values they obtained were lower than those found here despite their use of larger impellers. More recently, the same group 12 reported higher values for Ne, which can also be calculated with eq 1. For example, for D/T ) 0.264, C′ 1 /D = C b /D ) 1, and n b ) 6, A ) 45°(the "standard conditions" in this work), eq 1 predicts Ne to be 1.62.…”

Section: Resultsmentioning

confidence: 57%

“…For example, for D/T ) 0.264, C′ 1 /D = C b /D ) 1, and n b ) 6, A ) 45°(the "standard conditions" in this work), eq 1 predicts Ne to be 1.62. This value can be corrected by extrapolating the data in Rewatkar et al's Figure 9 12 to account for the different W/D ratio used here (0.177). The resulting value for Ne is approximately 1.5, i.e., very close to the value found here (1.49).…”

Section: Resultsmentioning

confidence: 99%

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Power Consumption in Stirred Tanks Provided with Multiple Pitched-Blade Turbines

Armenante

Mazzarotta

Chang

1999

Ind. Eng. Chem. Res.

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The power consumed by one, two, or three downward pumping, 45°six-blade pitched-blade turbines (6-PBTs) mounted on the same shaft was experimentally determined in stirred tanks under turbulent conditions. The power drawn by each individual impeller (in single-or multipleimpeller configurations), as well as the total power consumption, was measured with strain gauges mounted on the shaft and reported as individual or total power numbers. The power dissipated by single downward pumping, 45°four-blade pitched-blade turbines (4-PBTs) was also determined. Different combinations of the number of impellers, impeller diameter-to-tank diameter ratio, off-bottom clearance of the lowest impeller, C b1 , and spacing among impellers were tested. The overall power numbers of double 6-PBT systems were typically found to be smaller than twice the power number of a single 6-PBT. When C b1 was low and the upper impeller distant from the lower impeller, the power number of the lower impeller and the overall power number were higher. Reducing the distance between the impellers lowered the overall power number and that of the lower impeller. Similar results were obtained with three 6-PBTs. The results of this work can be used to predict the power consumed by individual impellers in multiple 6-PBT systems in a turbulent flow regime and to determine the optimal impeller configurations to minimize energy consumption.

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Section: Resultsmentioning

confidence: 57%

Section: Resultsmentioning

confidence: 99%

Power Consumption in Stirred Tanks Provided with Multiple Pitched-Blade Turbines

Armenante

Mazzarotta

Chang

1999

Ind. Eng. Chem. Res.

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“…Power number (N P ) of the hydrofoil (HF), 45°pitched blade turbine (PBT) and disc turbine (DT) are 0.27 [49], 1.73 [50] and 5.18 [50], respectively. To study the effect of impeller type on morphology and other properties of ADU, impeller rotational speed was taken at one level of 8.33 r/s and three impeller types were employed.…”

Section: Effect Of Type Of Impellersmentioning

confidence: 99%

Study on effect of process parameters and mixing on morphology of ammonium diuranate

Manna

Basak

Thakkar

et al. 2016

J Radioanal Nucl Chem

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Ammonium diuranate (ADU) is an important intermediate for the production of uranium base fuel. Controlling morphology of crystalline ADU powders is very important as it is retained by its subsequent products. Because of the high level of supersaturation, the involved mechanisms of precipitation like primary nucleation, crystal growth, aggregation and breakage occur simultaneously and they control the morphology. Effects of concentration of uranyl nitrate solution, temperature and the mixing intensity have been investigated on the morphology, crystal structure and the other physical properties of ADU. Effect of temperature is found to be more dominant for controlling morphology.

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“…When theliquid height is not equal to the vessel diameter, the length of circulation path for the case of PTD impeller is given by: impeller does not change with a change in the liquid height. This argument may be supported on the fact that the power number is independent of liquid height [Rewatkar et al (1990)]. …”

Section: Effect Of Impeller Diametermentioning

confidence: 99%

Effect of Impeller Design on Liquid Phase Mixing in Mechanically Agitated Reactors

Rewatkar

Joshi

1991

Chemical Engineering Communications

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Liquid phase mixing time (Ornix) was measured in mechanically agitated contactors of internal diameter 0.57 m, 1.0 m and 1.5 m. Tap water was used as the liquid phase. The impeller speed was varied in the range of 0.4-9.011s. Three types of impellers, namely disc turbine (DT), pitched blade downflow turbine (PTD) and pitched-blade upflow turbine (PTU) were employed. The ratio of impeller diameter to vessel diameter (DIT) and the ratio of impeller blade width to impeller diameter (WID) were varied over a wide range. The effects of impeller clearance from the tank bottom (C), the blade angle ($), the number of blades (n,), the blade thickness ( k ) and the total liquid height (HIT) were studied in detail. Mixing time was measured using the conductivity method.Mixing time was found to have a strong dependance on the flow pattern generated by the impeller. Mixing time was found to decrease by decreasing the impeller clearance in the case of DT and PTU. However in the case of PTD it increases with a decrease in the impeller clearance. Similar trend of the effect of impeller clearance on Omi, was observed for all the other PTD impellers with different diameter, number of blades and blade angle (except 60' and 90"). All the impeller designs were compared on the basis of power consumption and on this basis optimum design recommendations have been made. For PTD impellers, a correlation has been developed for the dimensionless mixing time. KEYWORDS Mixing time Row pattern and pumping capacity Pitched bladed turbine Impeller geometry Optimum impeller design.

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Power Consumption in Mechanically Agitated Contactors Using Pitched Bladed Turbine Impellers

Cited by 43 publications

References 9 publications

Power Consumption in Stirred Tanks Provided with Multiple Pitched-Blade Turbines

Power Consumption in Stirred Tanks Provided with Multiple Pitched-Blade Turbines

Study on effect of process parameters and mixing on morphology of ammonium diuranate

Effect of Impeller Design on Liquid Phase Mixing in Mechanically Agitated Reactors

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