Intrinsic viscosity reflects the capability of a polymer in solution to enhance the viscosity of the solution. Intrinsic Viscosity (): The ratio of a solution’s specific viscosity to the concentration of the solute, extrapolated to zero concentration.
Measured in stokes (St) or centistokes (cSt). Also known as the coefficient of kinematic viscosity. Kinematic Viscosity: The absolute viscosity of a fluid divided by the density of the fluid. There are many empirical and semi-empirical equations in literature to. Also known as coefficient of viscosity.Īpparent Viscosity: The value obtained by applying the instrumental equations used in obtaining the viscosity of a Newtonian fluid to viscometer measurements of a non-Newtonian fluidĭilute Solution Viscosity: The viscosity of a dilute solution of a polymer, measured under prescribed conditions, is an indication of the molecular weight of the polymer and can be used to calculate the degree of polymerization. Sediment increases the viscosity of the flow mixture.
These manual glass viscometers require the use of a Constant Temperature Bath in order to stabilize the sample temperature for measurement.Ībsolute Viscosity: The tangential force per unit area of two parallel planes at unit distance apart when the space between them is filled with a fluid and one plane moves with unit velocity in its own plane relative to the other. Dynamic viscosity (sometimes referred to as Absolute viscosity) is obtained by dividing the Shear stress by the rate of shear strain. Most the laboratory instruments use glass capillaries or “tubes”. There are several standardized capillaries in use. If you divide kinematic viscosity by the fluid density, you get absolute viscosity. In this paper, for calculation of numerical values of dynamic viscosity, at specific temperature, Vogel equation is used. Thus, dynamic viscosity is a measure of force, while kinematic viscosity is a measure of velocity.
develop the Navier-Stokes equation for the conservation of momentum. The more viscous an oil, then the longer it takes to flow via a capillary under the influence of gravity alone. Kinematic viscosity incorporates fluid density as part of its measurement. Common units for the two primary viscosity measurement types: dynamic and kinematic. Generally, measurements made using capillary viscometers rely on the relation between time and viscosity. The most common method for measuring kinematic viscosity is the use of a gravimetric capillary (Figure 1) that is usually temperature controlled at 40 ☌ and 100 ☌ for multigrade oils, and 40 ☌ for single grade oils. Video courtesy of Ekeeda - Measuring Kinematic Viscosity