Number of found documents: 77
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Edge Effects in Rotational Viscometry III. ZZ and KK Sensors, Total Slip Pseudosimilarity
Wein, Ondřej
2005 - English
The edge effects in AWS rotational viscometry are studied for materials, displaying the total slip at walls, i.e. negligible effect of the bulk shear flow. The found analytic asymptotes correspond to two asymptotic flow behaviour – for Newtonian liquids and ideal plastic materials. The explicit formulas on the edge-effect correction cL for this constitutionally extreme case are given for the ZZ40 according to ISO 3219 (1994) standard and the novel KK35/23 configuration of our own design. Hranové efekty v rotační viskometrie se zahrnutím zdánlivého skluzu při stěně (AWS) jsou teoreticky studovány pro materiály vykazující totální skluz, tj. zanedbatelný příspěvek objemového střihového toku. Nalezené analytické asymptoty odpovídají dvěma typům asymptotického tokového chování – pro Newtonské kapaliny a pro ideálně plastické materiály. Udány jsou explicitní vztahy pro hranové korekce, cL, pro tyto extrémní konstitutivní případy pro viskozimetry ZZ40 podle normy ISO 3219 (1994) a pro nový viskozimetr KK35/23 podle naší vlastní konstrukce. Keywords: slip at walls; rotational viscometry; edge effects Available at various institutes of the ASCR
Edge Effects in Rotational Viscometry III. ZZ and KK Sensors, Total Slip Pseudosimilarity

The edge effects in AWS rotational viscometry are studied for materials, displaying the total slip at walls, i.e. negligible effect of the bulk shear flow. The found analytic asymptotes correspond to ...

Wein, Ondřej
Ústav chemických procesů, 2005

Edge Effects in Rotational Viscometry II. ZZ (Couette) and KK (Coaxial Morse Cones) Sensors, No-slip Pseudosimilarity
Wein, Ondřej
2004 - English
This report is actually deals with corrections of edge effects for a wide spectrum of rotational viscometers with the cylinder-cylinder measuring sections. Tato zpráva udává korekce na hranové efekty pro široké spektrum rotačních viskozimetrů s měřicí sekcí válec-válec. Keywords: rotational viscometry; edge effects; newtonian media Available at various institutes of the ASCR
Edge Effects in Rotational Viscometry II. ZZ (Couette) and KK (Coaxial Morse Cones) Sensors, No-slip Pseudosimilarity

This report is actually deals with corrections of edge effects for a wide spectrum of rotational viscometers with the cylinder-cylinder measuring sections....

Wein, Ondřej
Ústav chemických procesů, 2004

Edge Effects in Rotational Viscometry. I. Cylinder - Cylinder (Couette) System, Newtonian Media
Wein, Ondřej; Večeř, Marek
2004 - English
Exact calibration factors for a series of commercially available rotational viscometers are determined by solving the related elliptic boundary-value problem for the rotational flow of Newtonian media under zero Reynolds number (creeping flow approximation). In particular, the edge-effect correction for the Z40 DIN sensor (coaxial cylinders) should be 1.085 instead of incorrect 1.100, given in the related international standard ISO 3219 (Coaxial cylinders for liquids of medium viscosity). The edge-effect correction was determined also for a new KK sensor (coaxial Morse cones) in dependence of the adjustable gap thickness. Přesné kalibrační konstanty u řady komerčně vyráběných viskozimetrů jsou stanoveny řešením odpovídajících okrajových úloh pro rotační tok newtonských kapalin s Reynoldsovým číslem nižším než nula (aproximace toku). Korekce na hranové efekty pro sensor Z40 DIN (koaxiální válce) by však místo nesprávné hodnoty 1.000 (uvedené v normě ISO 3219 (koaxiální válce pro kapaliny se střední viskozitou) měla být 1.085. Korekce hranových efektů byla určena také pro nový KK senzor (koaxiální Morse kužel). Keywords: rotational viscometry; newtonian media; edge correction Available at various institutes of the ASCR
Edge Effects in Rotational Viscometry. I. Cylinder - Cylinder (Couette) System, Newtonian Media

Exact calibration factors for a series of commercially available rotational viscometers are determined by solving the related elliptic boundary-value problem for the rotational flow of Newtonian media ...

Wein, Ondřej; Večeř, Marek
Ústav chemických procesů, 2004

Rotational Viscometry under Presence of Apparent Slip at Walls. VII. Torque and axial thrust in parallel-plate viscometer
Wein, Ondřej
2003 - English
An exact theory of the viscometric flow in the parallel-plate rheometer is analyzed numerically for the microdisperse liquids displaying apparent wall slip effect. Keywords: viscometry; normal stresses; apparent wall slip Available at various institutes of the ASCR
Rotational Viscometry under Presence of Apparent Slip at Walls. VII. Torque and axial thrust in parallel-plate viscometer

An exact theory of the viscometric flow in the parallel-plate rheometer is analyzed numerically for the microdisperse liquids displaying apparent wall slip effect.

Wein, Ondřej
Ústav chemických procesů, 2003

Rotational Viscometry under Presence of Apparent Slip at Walls VI. Basic Theory of ZZ, PP, KP, and KK Sensors (for VSWORK PC package under MS Windows)
Wein, Ondřej; Večeř, Marek
2003 - English
The theory of viscometric flow under apparent wall slip efefct is outlined. The working formulas for treating primary data of rotational viscometry are given. Keywords: slip; viscometry Available at various institutes of the ASCR
Rotational Viscometry under Presence of Apparent Slip at Walls VI. Basic Theory of ZZ, PP, KP, and KK Sensors (for VSWORK PC package under MS Windows)

The theory of viscometric flow under apparent wall slip efefct is outlined. The working formulas for treating primary data of rotational viscometry are given.

Wein, Ondřej; Večeř, Marek
Ústav chemických procesů, 2003

Electrodiffusion Diagnostics of Flow. Potentiostatic Transient under AWS Conditions
Wein, Ondřej
2003 - English
The initial period of this transient does not depend on the flow conditions. It gives the estimate of the complex nFcAD Keywords: electrodiffusion flow diagnostic; wall slip Available at various institutes of the ASCR
Electrodiffusion Diagnostics of Flow. Potentiostatic Transient under AWS Conditions

The initial period of this transient does not depend on the flow conditions. It gives the estimate of the complex nFcAD

Wein, Ondřej
Ústav chemických procesů, 2003

Behavior of Various Separators in Spouted Bed Electrowinning of Cooper
Jiřičný, Vladimír
2002 - English
The electrowinning cell of laboratory scale has been tested with various separators. Lifetime and conditions of dendrite formation have been determined for various separators in extended experimental study where effect of operation conditions as current density, temperature, electrolyte composition and impurities have been investigated. The copper deposition was used as a model system. Keywords: metal electrowinning; 3D electrode; copper Available at various institutes of the ASCR
Behavior of Various Separators in Spouted Bed Electrowinning of Cooper

The electrowinning cell of laboratory scale has been tested with various separators. Lifetime and conditions of dendrite formation have been determined for various separators in extended experimental ...

Jiřičný, Vladimír
Ústav chemických procesů, 2002

Calibration and Testing of Laboratory Electrolyser with Spouted Bed Cathode
Jiřičný, Vladimír
2002 - English
The electrowinning cell for metal deposition has been design, manufactured and tested. The laboratory size cell enable to be operated as a conventional electrolyser with slab-slab electrodes as well as un- or divided electrolyser with 3D cathode and variable thickness of cathode compartment. The calibration measurements are comparisons among various arrangements of the cell with respect to operation variables as temperature, electrolyte composition, current density, particle size and kind of separator. The copper deposition was used as a model system. Keywords: lab cell; slab-slab electrodes; operational variables Available at various institutes of the ASCR
Calibration and Testing of Laboratory Electrolyser with Spouted Bed Cathode

The electrowinning cell for metal deposition has been design, manufactured and tested. The laboratory size cell enable to be operated as a conventional electrolyser with slab-slab electrodes as well ...

Jiřičný, Vladimír
Ústav chemických procesů, 2002

Stability of the Newtonian Film Flow Down an Oscillating Inclined Plane. I. Orr-Sommerfeld Problem in a Long-Wave Asymptote
Wein, Ondřej; Tihon, Jaroslav
2001 - English
Stability of the film flow an oscillating inclined plane is analyzed. Following the previous analysis by Bauer and von Kerczek (1991), the 2D linearized equations of fluctuating motion around the primary (superposed oscillatory) flow field a for a Newtonian Fluid are analyzed. The long-wave (small wave number ?)asymptotic expansion in solved up to the order O(?). Keywords: film flow; stability; long-wave asymptote Available at various institutes of the ASCR
Stability of the Newtonian Film Flow Down an Oscillating Inclined Plane. I. Orr-Sommerfeld Problem in a Long-Wave Asymptote

Stability of the film flow an oscillating inclined plane is analyzed. Following the previous analysis by Bauer and von Kerczek (1991), the 2D linearized equations of fluctuating motion around the ...

Wein, Ondřej; Tihon, Jaroslav
Ústav chemických procesů, 2001

Dynamics of the Wavy Film Down an Inclined Plane. V. Newtonian Orr-Sommerfeld Problem Revisited
Wein, Ondřej; Tihon, Jaroslav
2001 - English
Linear stability of the Newtonian film flow along an inclined plate is studied by treating the related 2D linearized equations of fluctuating motion (Orr-Sommerfeld). Quadratic character of the Orr-Sommerfeld (OS) equations and the corresponding multiplicity of solution (the regular and singular branch) is demonstrated. Region of validity of both the long-wave (20 terms) and short-wave (4 terms) analytic asymptotes to the regular branch is estimated by comparing it with numerical solution to the full Orr-Sommerfeld problem. In particular, the c1-stability criterion of the regular long-wave asymptote is confirmed. In addition to the basic wave characteristics of the inception region (celerity, growth rate, wavelength), the characteristics of the fluctuating wall shear rate are given. Keywords: liquid film flow; Non-Newtonian fluid; flow instability Available at various institutes of the ASCR
Dynamics of the Wavy Film Down an Inclined Plane. V. Newtonian Orr-Sommerfeld Problem Revisited

Linear stability of the Newtonian film flow along an inclined plate is studied by treating the related 2D linearized equations of fluctuating motion (Orr-Sommerfeld). Quadratic character of the ...

Wein, Ondřej; Tihon, Jaroslav
Ústav chemických procesů, 2001

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