IS 1448 Pt.25-1976

标准号：IS 1448 Pt.25-1976
发布日期：1977/1/1 12:00:00
实施日期：1999/12/31 12:00:00
适用范围：1.1 This method describes a procedure for the determination of the kinematic viscosity of liquid petroleum products, both transparent and opaque, by mea-suring the time for a volume of liquid to flow under gravity through a cali-brated glass capillary viscometer. The dynamic viscosity can be obtained by multiplying the measured kinematic viscosity by the density of the liquid.1.2 The method is intended for application to liquids for which the ratio of shear stress to shear rate is the same for different viscometers ( Newtonian flow, see Note ).Note—The method depends on the behaviour of the sample and ideally the coefficient of viscosity should be independent of the rate of shear ( this is commonly called Newtonian flow behaviour). If, however, the coefficient of viscosity varies significantly with the rate of shear, different results may be obtained from viscometers of different capillary diameters.