Velocity profiles in steady and unsteady rotating flows for a finite cylndrical geometry. II.

Recently, research has shown that a settling process is an efficient treatment for the removal of suspended solids from storm sewage. In order to design settling tanks, there is a need to determine the settling velocity characteristics of these solids. Devices and test methods for measuring settling velocities of solids in storm sewage have been developed by researchers. A literature review has revealed that the settling velocity profiles obtained with some methods (Chebbo, 1992), (Michelbach and Wohrle, 1993) and (Tyack et al., 1993) are very different. In order to explain why the results are different and to quantify the influence of the experimental procedure on the settling velocity grading curves, we have compared the selected methods when tested with the same sample and we have studied the effects of the conservation of the sample before the test, of the concentration of solids in the device and of the nature of the water on the settling velocity profiles. The results of the comparative tests indicate that the settling velocities are significantly lower with both the Cergrene and Aston methods than with the UFT test procedure. Moreover, the study has shown that the settling characteristics of solids change with time, that the use of sewage liquor rather than demineralised water or drinking water can change the results of the measurement and that the higher the concentration of solids, the greater the velocity of settled particles.

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Velocity profiles of ferrofluids in a cylindrical container and in the presence of external rotating magnetic fields of high strength and frequency

Magnetohydrodynamics ◽

10.22364/mhd.56.4.1 ◽

2020 ◽

Vol 56 (4) ◽

pp. 341-368

Keyword(s):

Magnetic Fields ◽

High Strength ◽

Velocity Profiles ◽

Cylindrical Container ◽

Rotating Magnetic Fields

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Process characteristics of screw impellers with a draught tube for Newtonian liquids. Pumping capacity of the impeller

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19812021 ◽

1981 ◽

Vol 46 (9) ◽

pp. 2021-2031 ◽

Cited By ~ 6

Author(s):

Pavel Seichter

Keyword(s):

Viscous Liquid ◽

Energy Criterion ◽

Velocity Profiles ◽

Newtonian Liquid ◽

Creeping Flow ◽

Geometrical Arrangement ◽

Draught Tube ◽

Process Characteristics ◽

Newtonian Liquids

Velocity profiles and pumping capacity have been determined using a thermistor anemometer in a vessel equipped with a screw impeller. In region of the creeping flow of a Newtonian liquid, i.e. for Re <15, the dimensionless pumping capacity is dependent on the geometrical arrangement of the mixing system. The efficiency was assessed of individual configuration from the value energy criterion expressing the dimensionless power requirements for recirculation of a highly viscous liquid in a vessel equipped with a screw impeller.

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