双筒粘度计中的偏心效应

The Eccentric Effect of a Coaxial Viscometer

本文用摄动法研究了双筒式粘度计的内外筒不同心时对于测量粘度所引起的误差。算例表明，若问题的特征雷诺数越小，或者两筒的隙宽越窄，偏心所引起的测量误差越大，对于通常双筒粘度计的工作参数，只要两筒偏心距不超过两筒正常隙宽的１／１０所引起的测量误差是不大的。

This paper studies the effect of the eccentricity between the inner bob and the outer cup in a coaxial viscometer on the measurements of the viscosity by using a perturbation scheme.Our numerical examples demonstrate that the error incured by the eccentricity would become larger as the characteristic Reynolds number decreases or as the gap width between the bob and the cup gets narrower.Hnwever,such errors may not be significant of the eccentric distance is not larger than 1/10 of the gap width, for the usual working range of a coaxial viseometer.