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

1981 ◽  
Vol 46 (9) ◽  
pp. 2021-2031 ◽  
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.

Process characteristics of screw impellers with a draught tube for Newtonian liquids. Time of homogenization

1981 ◽  
Vol 46 (9) ◽  
pp. 2032-2042 ◽  
Author(s):  
Pavel Seichter
Keyword(s):  
Flow Regime ◽  
Creeping Flow ◽  
Energy Requirements ◽  
Dimensionless Time ◽  
Mixing Times ◽  
Conductivity Method ◽  
Draught Tube ◽  
Process Characteristics ◽  
Newtonian Liquids

A conductivity method has been used to assess the homogenization efficiency of screw impellers with draught tubes. The value of the criterion of homochronousness, i.e. the dimensionless time of homogenization, in the creeping flow regime of Newtonian liquids is dependent on the geometrical simplexes of the mixing system. In particular, on the ratio of diameters of the vessel and the impeller and on the ratio of the screw lead to the impeller diameter. Expression have been proposed to calculate the mixing times. Efficiency has been examined of individual configurations of screw impellers. The lowest energy requirements for homogenization have been found for the system with the ratio D/d = 2.

Process characteristics of screw impellers with a draught tube for Newtonian liquids. The power input

1981 ◽  
Vol 46 (9) ◽  
pp. 2007-2020 ◽  
Author(s):  
Pavel Seichter ◽  
Jiří Dohnal ◽  
František Rieger
Keyword(s):  
Reynolds Number ◽  
Experimental Verification ◽  
Power Input ◽  
Creeping Flow ◽  
Total Power ◽  
Geometrical Parameters ◽  
Draught Tube ◽  
Process Characteristics ◽  
Wide Range ◽  
Newtonian Liquids

An expression has been proposed for the power input of a screw impeller with a draught tube in the creeping flow regime based on the analogy with extruder screws. Experimental verification has confirmed practical utility of the expression in a wide range of geometrical parameters of the impeller and for the Reynolds number for mixing below 20. The total power input of the impeller is expressed as a sum of the input inducing the drag flow and the input to create the pressure flow. The former of the inputs may be deduced from the theory of extruders while an empirical approach based on experiment has been used to formulate an expression for the latter.

A Note on the Creeping Flow of a Viscous Liquid in the Region Between a Horizontal Plate and Moving Scraper

1971 ◽  
Vol 38 (4) ◽  
pp. 1056-1057
Author(s):  
J. R. Jones ◽  
T. S. Walters
Keyword(s):  
Viscous Liquid ◽  
Creeping Flow ◽  
Horizontal Plate ◽  
Flow Conditions ◽  
General Flow

The problem of flow of a viscous liquid in the region between a solid horizontal plate and a moving scraper is considered. The work of Rice and McAlister is extended to cover general flow conditions across the boundary.

Non-Newtonian slender drops in a nonlinear extensional flow

2019 ◽  
Vol 877 ◽  
pp. 561-581 ◽  
Author(s):  
Moshe Favelukis
Keyword(s):  
Stability Analysis ◽  
Power Law ◽  
Analytical Solutions ◽  
Viscosity Ratio ◽  
Extensional Flow ◽  
Shear Thinning ◽  
Newtonian Liquid ◽  
Creeping Flow ◽  
Stationary States ◽  
Power Law Index

In this theoretical report we explore the deformation and stability of a power-law non-Newtonian slender drop embedded in a Newtonian liquid undergoing a nonlinear extensional creeping flow. The dimensionless parameters describing this problem are: the capillary number $(Ca\gg 1)$, the viscosity ratio $(\unicode[STIX]{x1D706}\ll 1)$, the power-law index $(n)$ and the nonlinear intensity of the flow $(|E|\ll 1)$. Asymptotic analytical solutions were obtained near the centre and close to the end of the drop suggesting that only Newtonian and shear thinning drops $(n\leqslant 1)$ with pointed ends are possible. We described the shape of the drop as a series expansion about the centre of the drop, and performed a stability analysis in order to distinguish between stable and unstable stationary states and to establish the breakup point. Our findings suggest: (i) shear thinning drops are less elongated than Newtonian drops, (ii) as non-Newtonian effects increase or as $n$ decreases, breakup becomes more difficult, and (iii) as the flow becomes more nonlinear, breakup is facilitated.

A neutrally buoyant sphere in creeping flow between parallel plates: farfield velocity profiles

1990 ◽  
Vol 45 (1) ◽  
pp. 225-235
Author(s):  
Jeffrey A. Schonberg ◽  
Donald A. Drew ◽  
Georges Belfort
Keyword(s):  
Velocity Profiles ◽  
Creeping Flow ◽  
Parallel Plates ◽  
Neutrally Buoyant

Modeling of Newtonian and Non-Newtonian Liquid Sloshing in Road Tanks while Braking

2014 ◽  
Vol 611 ◽  
pp. 137-144 ◽  
Author(s):  
Alexandr Shimanovsky ◽  
Maryna Kuzniatsova ◽  
Alžbeta Sapietová
Keyword(s):  
Finite Element ◽  
Energy Dissipation ◽  
Finite Element Modeling ◽  
Newtonian Liquid ◽  
Liquid Sloshing ◽  
Element Modeling ◽  
Newtonian Liquids

Finite element modeling of the Newtonian and non Newtonian liquids oscillations in the cylindrical transport reservoir at its braking was performed. The peculiarities of the Newtonian, Ostwald de Waele and Bingham models of liquid sloshing in tank with internal perforated baffles and without them were analyzed. There were obtained the dependences of hydrodynamic pressures and liquid energy dissipation for Newtonian and non Newtonian liquids considering the different filling level of the reservoir.

The Taylor–Saffman problem for a non-Newtonian liquid

1990 ◽  
Vol 220 ◽  
pp. 413-425 ◽  
Author(s):  
S. D. R. Wilson
Keyword(s):  
Shear Thinning ◽  
Newtonian Liquid ◽  
Power Law Model ◽  
Oldroyd Fluid ◽  
Partial Explanation ◽  
Oldroyd Model ◽  
Fingering Instability ◽  
Newtonian Liquids ◽  
Hydrodynamical Theory ◽  
Hele Shaw Cell

The Taylor–Saffman problem concerns the fingering instability which develops when one liquid displaces another, more viscous, liquid in a porous medium, or equivalently for Newtonian liquids, in a Hele-Shaw cell. Recent experiments with Hele-Shaw cells using non-Newtonian liquids have shown striking qualitative differences in the fingering pattern, which for these systems branches repeatedly in a manner resembling the growth of a fractal. This paper is an attempt to provide the beginnings of a hydrodynamical theory of this instability by repeating the analysis of Taylor & Saffman using a more general constitutive model. In fact two models are considered; the Oldroyd ‘Fluid B’ model which exhibits elasticity but not shear thinning, and the Ostwald–de Waele power-law model with the opposite combination. Of the two, only the Oldroyd model shows qualitatively new effects, in the form of a kind of resonance which can produce sharply increasing (in fact unbounded) growth rates as the relaxation time of the fluid increases. This may be a partial explanation of the observations on polymer solutions; the similar behaviour reported for clay pastes and slurries is not explained by shear-thinning and may involve a finite yield stress, which is not incorporated into either of the models considered here.

A Numerical Study on Flow Characteristics of 2D Vertical Liquid Jet Striking a Horizontal Surface

2010 ◽  
Author(s):  
M. Kimiaghalam ◽  
M. Passandideh-Fard
Keyword(s):  
Reynolds Number ◽  
Hydraulic Jump ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Newtonian Liquid ◽  
Liquid Jets ◽  
Liquid Jet ◽  
Moderate Reynolds Number ◽  
Different Types ◽  
Newtonian Liquids

We studied numerically impingement of vertical liquid jets of moderate Reynolds number for both Newtonian and non-Newtonian liquids to clarify the structure formation of circular hydraulic jump and the phenomenon of jet buckling. First, we have studied the hydraulic jump characteristics and governing parameters for a laminar water jet. Moreover, different types of hydraulic jump have been investigated by varying the height of a circular wall around the bed in flow downstream. The results show that a circular hydraulic jump has two kinds of steady states which can be reached by changing wall height. Next, we studied the impingement of a non-Newtonian liquid jet on a solid surface. In this case, we observe that instead of having a significant hydraulic jump, jet buckling phenomenon happens. The results were used in order to achieve a better understanding of the jet buckling phenomenon and the conditions in which this phenomenon happens.

Non-Newtonian Liquid Blade Coating Process

1982 ◽  
Vol 104 (4) ◽  
pp. 469-474 ◽  
Author(s):  
S. S. Hwang
Keyword(s):  
Experimental Data ◽  
Film Thickness ◽  
Liquid Film ◽  
Thin Liquid Film ◽  
Newtonian Liquid ◽  
Air Pressure ◽  
Coating Process ◽  
Newtonian Liquids ◽  
Calculated Liquid ◽  
Blade Coating

A blade coating process for non-Newtonian liquids is presented using different air pressure applied at the inlet and the exit of the coating gap. The system consists of a coating blade to form a gap and a vacuum box to create different air pressures to permit coating a thin liquid film on an advancing plastic web. The solution consists of matching the boundary conditions of each subregion of the coating process. The calculated liquid film thickness as a function of the coating gap and applied air pressure difference agrees closely with experimental data obtained on a laboratory coating device.

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