Viscosimetry


Also found in: Dictionary, Thesaurus, Medical, Wikipedia.
Related to Viscosimetry: viscometry

Viscosimetry

 

a branch of physics devoted to methods of measuring viscosity. The reasons for the substantial variety of methods and designs of equipment for measuring viscosity (viscosimeters) are both the wide range of values of viscosity (from 10-5 nanosec/m2 for gases to 1012 nanosec/m2 for a number of polymers) and the necessity for measuring it at low or high temperatures and pressures (for example, compressed gases, molten metals, and water vapor under high pressures).

The three most widely used methods of measuring the viscosity of liquids and gases are the capillary method, the falling sphere method, and the method of coaxial cylinders (rotation method). They are based respectively upon Poiseuille’s law, Stokes’ law, and the law of the flow of a liquid between coaxial cylinders. Viscosity is also determined according to the extinguishing of periodic oscillations of a plate placed in the medium to be investigated.

There is a special group of methods of viscosity measurement which use small volumes of the medium (micro-viscosity). These methods are based on the observation of Brownian motion, mobility of ions, and particle diffusion.

REFERENCES

Barr, G. Viskozimetriia. Leningrad-Moscow, 1938. (Translated from English.)
Targ, S. M. Osnovye zadachi teorii laminarnykh techenii. Moscow, 1951.
Fuks, G. I. Viazkost’ i plastichnost’ nefteproduktov. Moscow, 1951.
Golubev, I. F. Viazkost’ gazov i gazovykh smesei. Moscow, 1959.
Mentioned in ?
References in periodicals archive ?
A Brookficld viscometer (Visco Basic Plus* from Fun-gilab) was used in the viscosimetry tests.
Resin SR[R]1500 LY556 Pre-cure 2 to 4 h @ 2 to 4 h @ 20[degrees]C 80[degrees]C OR 1 lo 3 h @ 90[degrees]C Minimum 2 to 7 days @ n/a post-cure 20[degrees]C cycle Advised 2 to 7 days @ 4 to 8 h @ post-cure 20[degrees]C 120[degrees]C cycle OR OR 12 h @ 2 to 8 h @ 40[degrees]C 140[degrees]C OR 6 h @ 60[degrees]C OR 2 to 8 h @ 160[degrees]C Cycle up to gelation @ 2 hours @ selected for 30[degrees]C; 30[degrees]C + viscosimetry up lo gelation @ up lo gelalion @ tests 40[degrees]C; 80[degrees]C up to gelation @ 50[degrees]C Cycle up to 100 Pa.
The direct outputs from both viscosimetry and rheometry are graphically represented in Figs.
The values found by both viscosimetry and rheometry for the initial viscosity.
In the SR" 1500 viscosimetry tests a consistent decrease in viscosity was observed in early stages of the lesls up to the moment where a fast gelation occurred.
Further analysis of the viscosimetry data revealed that the thermal energy, Ej,generated within the resin samples from the beginning of the tests (initial temperature, [T.
It is observable lhal the cure progress (conversion) achieved in the viscosimetry lesls of SR"1500 is very low for all temperatures.
The shape of the SRM500 viscosimetry curves, uncommon for "nearly" isothennal tests, implied the development of a dedicated description lhal enforced the temperature dependence of the viscosity.
This model was successfully applied to fit experimental data with similar profile lo the SR*I5(X) viscosimetry studied herewith, i.