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Edge Effects in Rotational Viscometry VI. ZZ- and KK- Type Sensors: No-slip Pseudosimilarity for Inertialess Flow (Revisited)
Wein, Ondřej ; Havlica, Jaromír
This report should serve as a manual to the program Prog_cL_m.exe for calculating the correction cL on edge effects in narrow-gap rotational viscometry with almost cylindrical or conical spindles. Referring to the previous Research Report ICPF 2004/8, which deals with the same subject, it includes, in addition, also computation of cL for the entire ZZ and KK sensors with an arbitrary front of bottom semi-sensors (FLAT, CONE, HUB, HAAKE). Detailed attention is paid to numerical aspects: extrapolation/interpolation of the related fields (angular velocity, shear stress, dissipation, local torque contribution) towards the boundaries, including the analytical smoothing at singularities. The source codes for Prog_cL_m.exe, the results of numerical simulations, as well as the resulting correlations for cL , are available on the attached CD, which is an integral part of this report. The inertia effect was computed using commercial software FLUENT 12 for the Z40DIN sensor and applied in an approximate way also for the KK35/23 sensor.
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EDWork 3. Příručka k softwaru EDWork
Wein, Ondřej
A reference guide to EDWork, a software for controlling, calibrating, and adjusting the device EDIK2 for electrodiffusion measurements, as well as the acquisition and treatment of the resulting electrodiffusion dat.
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Hranové efekty v rotační viskozimetrii IV. ZZ (Couette) senzory, bez skluzu, skutečná viskozitní funkce.
Wein, Ondřej
Neglect of end effects in Couette rotational viscometry introduces 10-30% error in the estimate of shear stress at spindle surface. Actual deviations depend on the shear-thinning level of a given sample. We tackle the end effect for the standard sensor Z40 DIN according to ISO 3219 by solving the related 2D boundary-value problem for a class of shear-thinning viscosity functions. Pseudosimilarity method of treating the primary data leaves an error in shear stresses about 0.5%. Further reduction of the errors needs a full numerical simulation for each point of primary data, based on a suitable wide-range representation of the viscosity function. To support high accuracy of torque calibrations, the effect of inertia on torque for Newtonian liquids in standard sensor Z40 DIN at Re < 500 is calculated using the FLUENT 6.2 commercial software.
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Koncové efekty v rotační viskometrii za přítomnosti zdánlivého skluzu
Wein, Ondřej ; Večeř, Marek ; Havlica, Jaromír
Common methods of treating primary data from rotational viscometry are tested using numerical simulations of primary circular flow of shear-thinning liquids in an actual sensor Z40 DIN according to ISO 3219 and a new KK (Morse-taper) sensor, suggested for rotational viscometry under slip effect. Theory of the sensors is presented, including the conversion of primary data into fluidity and slip viscometric material functions, as well as a statistical analysis of their relevance. The data treatment, based on the concept of local filtration, is illustrated on several aqueous solutions of Hercules CMC and Welan gum.
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