Projeto, construção e ensaio de um viscosimetro capilar

AUTOR(ES)
DATA DE PUBLICAÇÃO

1982

RESUMO

A capillary type rheometer which operates coupled to the universal testing machine INSTRON model 11303, was designed, built and tested. The rheometer has basically a reservoir that contain the testing material and a capillary tube through which the ma¬terial has to flow steadly at a constant rate and laminar regime in order to detect the pressure drop that gives the shearing stress meanwhile the flow rate enhances the determination of the shear rate. A combination of several different speeds of the testing machine together with the tubes of different length and diameter gives the parameters shear stress and shear rate that lead to adjust a model of rheological behaviour to the material under test. The rheometer has a wide range of operation with shear rate ranging from 1 s-l to 60,000 s-1, and fluids with apparent viscosity ranging from 1.0 cP to 2.5.105 cP. Tests were conducted with three differents fluids: lubricating oil SAE 40 and glycerin that behaved as Newtonian and an aqueous solution 3% by weight of CMC that presented a pseudoplastic behaviour. Results were analysed through two statistical parameters: correlation ratio "r2" and Snedeaor distribution coefficient "F". The statistical analysis led to the conclusion that the rheometer designed presents an high degree of confidence by the performance presented and the quality of the rheological parameters obtained.

ASSUNTO(S)

capilaridade reologia viscosimetro

ACESSO AO ARTIGO

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