1. GUJARAT TECHNOLOGICAL UNIVERSITY
Chandkheda, Ahmadabad
Affiliated
SHROFF S.R. ROTARY INSTITUTE OF CHEMICAL TECHNOLOGY
AN
OPEN ENDED PROJECT
On
Viscosity Measurement Methods
Under subject of
Fluid Mechanics
B. E. Semester – IV
Mechanical Engineering
Submitted by:
Name Enrollment Number
Gaurang patel 170990119011
Kiran Patel 170990119012
Vinay Patel 170990119014
Dhananjay Patel 170990119015
Dhyey Shukla 170990119016
Safiuddin Siddique 170990119017
Aman Singh 170990119018
Mihir Suman 170990119019
Aakash Tamakuwala 170990119020
Pratik Tejani 170990119021
Arun Vasava 170990119022
Mr. Shivang Ahir (Faculty Guide) Mr. Samir Jariwala (Head Of Department) Academic Year- (2018-19)
2. VISCOSITY MEASUREMETN METHODS
CERTIFICATE
This is to certify that project work embodied in this report Entitled “ Viscosity Measurement
Methods” was carried out by
Name Enrollment Number
Gaurang patel 170990119011
Kiran Patel 170990119012
Vinay Patel 170990119014
Dhananjay Patel 170990119015
Dhyey Shukla 170990119016
Safiuddin Siddique 170990119017
Aman Singh 170990119018
Mihir Suman 170990119019
Aakash Tamakuwala 170990119020
Pratik Tejani 170990119021
Arun Vasava 170990119022
studying at Shroff S.R. Rotary Institute Of Chemical Technology code no. 099 for partial
fulfillment of the subject. PROCESS HEAT TRANSFER. This project work has been carried
out under my guidance and supervision and it is up to my satisfaction.
Date:
Name of Faculty:-
Shivang Ahir
Signature:-
3. VISCOSITY MEASUREMETN METHODS
ACKNOWLEDGEMENT
We would like to express us sincere gratitude to Mr. Shivang Ahir for
his guidance. The technical discussions with Mr. Shivang Ahir always
very insightful, and we will always be indebted to his for all the
knowledge he has shared with us. His prompt responses and
availability despite his busy schedule were truly appreciated. The
reality is that MrShivang Ahir was much more than an advisor to us.
He always helped us in all technical and non-technical issues during
my period of work.
5. VISCOSITY MEASUREMETN METHODS
Abstract
Viscosity is measured with various types of viscometers and rheometers. A rheometer is used for those
fluids that cannot be defined by a single value of viscosity and therefore require more parameters to be
set and measured than is the case for a viscometer. Close temperature control of the fluid is essential to
acquire accurate measurements, particularly in materials like lubricants, whose viscosity can double with
a change of only 5 °C.
For some fluids, the viscosity is constant over a wide range of shear rates (Newtonian fluids). The fluids
without a constant viscosity (non-Newtonian fluids) cannot be described by a single number. Non-
Newtonian fluids exhibit a variety of different correlations between shear stress and shear rate.
One of the most common instruments for measuring kinematic viscosity is the glass capillary viscometer.
In coating industries, viscosity may be measured with a cup in which the efflux time is measured. There
are several sorts of cup – such as the Zahn cup and the Ford viscosity cup – with the usage of each type
varying mainly according to the industry. The efflux time can also be converted to kinematic viscosities
(centistokes, cSt) through the conversion equations.
Also used in coatings, a Stormer viscometer uses load-based rotation in order to determine viscosity.
The viscosity is reported in Krebs units (KU), which are unique to Stormer viscometers.
Vibrating viscometers can also be used to measure viscosity. Resonant, or vibrational viscometers work
by creating shear waves within the liquid. In this method, the sensor is submerged in the fluid and is
made to resonate at a specific frequency. As the surface of the sensor shears through the liquid, energy
is lost due to its viscosity. This dissipated energy is then measured and converted into a viscosity reading.
A higher viscosity causes a greater loss of energy.
Extensional viscosity can be measured with various rheometers that apply extensional stress.
Volume viscosity can be measured with an acoustic rheometer.
Apparent viscosity is a calculation derived from tests performed on drilling fluid used in oil or gas well
development. These calculations and tests help engineers develop and maintain the properties of the
drilling fluid to the specifications required.
6. VISCOSITY MEASUREMETN METHODS
Introduction
The viscosity of a fluid is a measure of its resistance to deformation at a given
rate.
For liquids, it corresponds to the informal concept of "thickness":
for example, syrup has a higher viscosity than water.
Viscosity can be conceptualized as quantifying the frictional force that arises
between adjacent layers of fluid that are in relative motion.
For instance, when a fluid is forced through a tube, it flows more quickly near
the tube's axis than near its walls.
In such a case, experiments show that some stress (such as a pressure
difference between the two ends of the tube) is needed to sustain the flow
through the tube.
This is because a force is required to overcome the friction between the layers
of the fluid which are in relative motion: the strength of this force is
proportional to the viscosity.
A fluid that has no resistance to shear stress is known as an ideal or inviscid
fluid.
Zero viscosity is observed only at very low temperatures in superfluids.
Otherwise, the second law of thermodynamics requires all fluids to have
positive viscosity; such fluids are technically said to be viscous or viscid. A
fluid with a relatively high viscosity, such as pitch, may appear to be a solid.
7. VISCOSITY MEASUREMETN METHODS
Viscosity
Viscosity is the material property which relates the viscous stresses in a material to the rate of change
of a deformation (the strain rate). Although it applies to general flows, it is easy to visualize and define
in a simple shearing flow, such as a planar Couette flow.
In the Couette flow, a fluid is trapped between two infinitely large plates, one fixed and one in parallel
motion at constant speed ‘u’. If the speed of the top plate is low enough (to avoid turbulence), then in
steady state the fluid particles move parallel to it, and their speed varies from at the bottom to ‘u’ at
the top. Each layer of fluid moves faster than the one just below it, and friction between them gives
rise to a force resisting their relative motion. In particular, the fluid applies on the top plate a force in
the direction opposite to its motion, and an equal but opposite force on the bottom plate. An external
force is therefore required in order to keep the top plate moving at constant speed.
In many fluids, the flow velocity is observed to vary linearly from zero at the bottom ‘u’ at the top.
Moreover, the magnitude ‘F’ of the force acting on the top plate is found to be proportional to the
speed ‘u’ and the area
‘A’ of each plate, and inversely proportional to their separation‘y’:
The proportionality factor ′𝜇′ is the viscosity of the fluid, with units of (pascal -second). The ratio
‘u/y’ is called the rate of shear deformation or shear velocity, and is the derivative of the fluid speed
in the direction
perpendicular to the plates (see illustrations to the right). If the velocity does not vary linearly with
‘y’, then the appropriate generalizationis:
Where ’, and ‘ ’ is the local shear velocity. This expression is referred to as Newton's law of
viscosity.
In shearing flows with planar symmetry, it is what defines ‘ ’ . It is a special case of the general
definition of viscosity,which can be expressed in coordinate-free form.
Types of Viscosity,
Dynamic
Kinematic
9. VISCOSITY MEASUREMETN METHODS
Capillary Viscometer
The viscosity of Newtonian fluids can be most precisely determined using capillary
viscometers.
This method of measurement, measures the time taken for a defined quantity of fluid to
flow through a capillary with a known diameter and known length.
With the industrial production of such precisely calibrated capillary viscometers, we
have created the conditions to enable this measuring method to establish itself worldwide
as a reliable procedure.
With the development of the first automatic measuring systems, we replaced the
stopwatch with automatic registration of the fluid at the start of the 1970’s. Since then,
subjective measuring errors have been a thing of the past.
10. VISCOSITY MEASUREMETN METHODS
Rotational Viscometer
Rotational viscometers have become a standard in virtually all industries. They measure
viscosity by sensing the torque required to rotate a spindle at constant speed while
immersed in fluid. The torque is proportional to the viscous drag on the spindle; thus the
sample viscosity.
Rotational viscometers offer several advantages:
The continuous rotation of the spindle allows measurements to be made over time,
permitting analysis of time-dependent fluids
The rate of shear is constant, so both Newtonian and non-Newtonian fluids can be tested
By rotating the spindle at several different speeds, shear dependent behavior can be
analyzed
Rotational viscometers are the industry standard in determining absolute viscosity of all
types of liquids with viscosities as high as 320 million centipoise. BYK-Gardner offers
digital models for low– medium – high viscosity materials
11. VISCOSITY MEASUREMETN METHODS
Falling Sphere Viscometer
The Falling Ball Viscometer uses the simple, but precise, “Höppler” principle to measure
the viscosity Newtonian fluids by measuring the time required for a ball to fall under
gravity through a sample-filled tube.
The “Höppler” principle is used to measure the viscosity of Newtonian liquid by
measuring the time required for a ball to fall under gravity through a sample-filled tube
that is inclined at an angle. The average time of three tests is taken; the result is converted
into a viscosity value using a simple formula.
KF40 can be angled at 50°, 60°, 70° and 80°
12. 12
VISCOSITY MEASUREMETN METHODS
Vibrational Viscometer
Vibrational viscometers date back to the 1950s Bendix instrument, which is of a class that operates by
measuring the damping of an oscillating electromechanical resonator immersed in a fluid whose viscosity is
to be determined. The resonator generally oscillates in torsion or transversely (as a cantilever beam or tuning
fork). The higher the viscosity, the larger the damping imposed on the resonator. The resonator's damping may
be measured by one of several methods:
Measuring the power input necessary to keep the oscillator vibrating at a constant amplitude. The higher the
viscosity, the more power is needed to maintain the amplitude of oscillation.
Measuring the decay time of the oscillation once the excitation is switched off. The higher the viscosity, the
faster the signal decays.
Measuring the frequency of the resonator as a function of phase angle between excitation and response
waveforms. The higher the viscosity, the larger the frequency change for a given phase change.
The vibrational instrument also suffers from a lack of a defined shear field, which makes it unsuited to
measuring the viscosity of a fluid whose flow behaviour is not known beforehand.
Vibrating viscometers are rugged industrial systems used to measure viscosity in the process condition. The
active part of the sensor is a vibrating rod. The vibration amplitude varies according to the viscosity of the
fluid in which the rod is immersed. These viscosity meters are suitable for measuring clogging fluid and high-
viscosity fluids, including those with fibers (up to 1000 Pa·s). Currently, many industries around the world
consider these viscometers to be the most efficient system with which to measure the viscosities of a wide
range of fluids; by contrast, rotational viscometers require more maintenance, are unable to measure clogging
fluid, and require frequent calibration after intensive use. Vibrating viscometers have no moving parts, no
weak parts and the sensitive part is very small. Even very basic or acidic fluids can be measured by adding a
protective coating, such as enamel, or by changing the material of the sensor to a material such as 316L
stainless steel
13. 13
VISCOSITY MEASUREMETN METHODS
VROC Viscometer
VROC™ is the leading automated, small sample viscometer used worldwide by Fortune
Global 500 companies and leading research universities. Capable of the most demanding
applications including small sample protein therapeutics, m-VROC™ features the widest
dynamic range (high shear rate viscosity measurements up to 1,400,000 s-1
) with as little
as 20 microliters of sample.
Accuracy: 2% of Reading
Repeatability: 0.5% of Reading
Viscosity Range: 0.2 ~ 100,000 mPa-s (or cP)
Shear Rate Range: 0.5 ~ 1,400,000 s -1
Small Sample Volume: 20 µL + Viscometer
Dimensions: 10" x 15.5" x 7
14. 14
VISCOSITY MEASUREMETN METHODS
REFERENCE
1. Barnes, H. A.; Hutton, J. F.; Walters, K. (1989). An introduction to rheology (5. impr.
ed.). Amsterdam: Elsevier. p. 12. ISBN 978-0-444-87140-4.
2. ^ W. P. Mason, M. Hill: Measurement of the viscosity and shear elasticity of liquids by
means of a torsionally vibrating crystal; Transactions of the ASME. In: Journal of
Lubricating Technology. Band 69, 1947, S. 359–370.
3. ^ Berthold Bode: Entwicklung eines Quarzviskosimeters für Messungen bei hohen
Drücken. Dissertation der TU Clausthal, 1984.
4. ^ "Archived copy". Archived from the original on 2015-07-02. Retrieved 2015-07-
02.<|accessdate=2015-07-02 |
5. ^ Beitz, W. and Küttner, K.-H., English edition by Davies, B. J., translation by Shields,
M. J. (1994). Dubbel Handbook of Mechanical Engineering. London: Springer-Verlag
Ltd., p. F89.
6. ^ Jump up to:a b
ASTM Paint and Coatings Manual 0-8031-2060-5.
• British Standards Institute BS ISO/TR 3666:1998 Viscosity of water
• British Standards Institute BS 188:1977 Methods for Determination of the viscosity of liquids
)