Viscosity Measurement
Objectives for the student:
1. Learn to operate and take data with a rotating spindletype viscometer
2. Investigate 10W30 oil is a Newtonian or nonNewtonian fluid
3. Determine the viscosity of 10W30 motor oil as a function of temperature
Introduction
Rheology is defined as the science of the deformation and flow of matter (BSR, 1998). It is
important for Mechanical Engineers especially dealing with fluid flow and tribology (the science
of lubrication). One physical quantity important in the rheology of fluids is viscosity. Viscosity is
defined as the ratio of shear stress to shear rate in the fluid. A fluid for which viscosity is
constant at all shear rates is called a ‘Newtonian’ fluid. Examples of Newtonian fluids include:
water, sugar solutions, glycerin, silicone oils, lighthydrocarbon oils, air and other gases
(Schlumberger, 2002). A fluid, whose viscosity is not constant, but varies as a function of shear
rate is called a ‘nonNewtonian’ fluid. Examples of nonNewtonian fluids are drilling fluids,
some kinds of oils, some kinds of paints, polymer melts, etc. A good overview of the most
common types of nonNewtonian fluid behaviors is given in the Brookfield publication “More
Solutions to Sticky Problems”,
http://www.brookfieldengineering.com/support/documentation/index.cfm.
While many lubricating oils are Newtonian, their viscosities are highly temperature dependent. It
is important to know the viscosity and how it varies with temperature in the design of lubrication
systems, fluid transport, etc. This lab will introduce the student to one method of making
viscosity measurements.
Theory
Several sources that you may find helpful for the theoretical background on viscosity are:
•
http://www.phys.virginia.edu/classes/311/notes/fluids2/node2.html
,
•
http://scienceworld.wolfram.com/physics/DynamicViscosity.html
,
•
http://hyperphysics.phyastr.gsu.edu/hbase/pfric.html#vis
,
•
http://www.brookfieldengineering.com/support/viscosity/index.cfm
,
•
your fluids textbook, or your machine design textbook
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 '10
 Mysore,Ananda
 Double click, viscometer head, Viscometer Programs

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