Rheological test can be very helpful tools for polymer processing and development. This presentation is designed to be an informative introduction and guide to rheological tests, and finding correlations between equipment and processing techniques.
Rheology is the investigation of the progression of issue, fundamentally in a fluid state, yet in addition as "delicate solids" or solids under conditions in which they react with plastic stream as opposed to distorting flexibly because of an applied power. Rheology is the study of misshapening and stream inside a material.
Rheological test can be very helpful tools for polymer processing and development. This presentation is designed to be an informative introduction and guide to rheological tests, and finding correlations between equipment and processing techniques.
Rheology is the investigation of the progression of issue, fundamentally in a fluid state, yet in addition as "delicate solids" or solids under conditions in which they react with plastic stream as opposed to distorting flexibly because of an applied power. Rheology is the study of misshapening and stream inside a material.
Rheology is the science that study flow of fluids. Viscosity is the main parameter of flow. Newtonian & non newtonian are the two types of flow behavior according to newtons law of flow. non-newtonian flow can be plastic, pseudoplastic, dilatant, thixotropic, antithixotropic or rheopexy. viscosity can be determined by using various viscometers such as capillary viscometer, cup & bob viscometer, cone & plate viscometer, falling sphere viscometer, brookfield viscometer, etc. factors affeting viscosity are intrinsic, extrinsic or temperature dependence.
This presentation related to molecular diffusion of molecules in gases and liquids. Also includes inter-phase mass transfer and various theories related to it like two film theory, penetration theory and surface renewal theory.
Agitation and Mixing are two important unit operations used in industries such as Impellers agitators are widely used to circulate the liquid through the vessel in which the dispersion of liquids and gases into other liquids like mixing of stiff paste, elastomers and dry solids powders takes place.
Rheology is the science that study flow of fluids. Viscosity is the main parameter of flow. Newtonian & non newtonian are the two types of flow behavior according to newtons law of flow. non-newtonian flow can be plastic, pseudoplastic, dilatant, thixotropic, antithixotropic or rheopexy. viscosity can be determined by using various viscometers such as capillary viscometer, cup & bob viscometer, cone & plate viscometer, falling sphere viscometer, brookfield viscometer, etc. factors affeting viscosity are intrinsic, extrinsic or temperature dependence.
This presentation related to molecular diffusion of molecules in gases and liquids. Also includes inter-phase mass transfer and various theories related to it like two film theory, penetration theory and surface renewal theory.
Agitation and Mixing are two important unit operations used in industries such as Impellers agitators are widely used to circulate the liquid through the vessel in which the dispersion of liquids and gases into other liquids like mixing of stiff paste, elastomers and dry solids powders takes place.
Unit 3 introduction to fluid mechanics as per AKTU KME101TVivek Singh Chauhan
strictly following syllabus of KME 101T of AKTU for first yr 2021
fluid properties, bernoulli's equation with proof and numericals , pumps, turbine , hydraulic lift, continuity equation
FMM- UNIT I FLUID PROPERTIES AND FLOW CHARACTERISTICSKarthik R
Units and dimensions- Properties of fluids- mass density, specific weight, specific volume,
specific gravity, viscosity, compressibility, vapor pressure, surface tension and capillarity. Flow
characteristics – concept of control volume - application of continuity equation, energy
equation and momentum equation.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
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Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
1. ERT 142 Engineering Properties of Bio
Materials
Biosystems Engineering
School of Bioprocess Engineering
2. Rheology
rheo – to flow
logos – science
ology – the study of
is the study of the flow of materials that
behave in an interesting or unusual
manner.
Unusual materials such as mayonnaise,
peanut butter, chocolate, bread dough,
paints, inks, road building aterials,
cosmetics, dairy products, etc.
3. Rheology
The study of viscosity is of true liquids,
solutions, dilute and concentrated
colloidal systems is of much importance
in this study
It is involved in the mixing and flow of
materials, their packaging into
containers, the pouring from the bottle,
extrusion from a tube or a passage of
the liquid to a syringe needle.
4. Rheology
Can affect the patient’s acceptability of
the product, physical stability, biologic
availability, absorption rate of drugs in
the gastrointestinal tract
Influence the choice of processing
equipments in the pharmaceutical
system
5. What is a Fluid ? (Fluid vs. Solid)
• A substance which deforms continuously under the
action of a shearing stress.
• A perfectly elastic solid can resist a shear stress by
static deformation; a fluid cannot.
• An elastic solid can behave like a fluid beyond its
yield point, at which point it behaves as a "plastic".
• Viscoelastic fluids behave like fluids and solids (i.e.
egg whites, which have a small tendency to return
to their original shape).
Corollary: A fluid at rest must be in a state of zero
shear stress.
6. Liquid vs. Gas
• Gases typically expand to fill the shape of container.
• Liquids assume shape of only part of container.
• Equation of state for pressure
• Gases typically obey equations of state for the
pressure e.g. the ideal gas law
p = ρ R T
• Liquids are typically assumed to be incompressible
and so p is a very weak function of ρ and T.
• Sound speed in gases is typically smaller than in liquids
(air ~ 343 m/s, water ~ 1484 m/s, iron 5120 m/s).
7. NEWTON’S LAW AND VISCOSITY
Some of the food substances are in the form of LIQUID.
One of the PHYSICAL PROPERTIES FOR LIQUID FOOD
VISCOSITY (Kelikatan).
REASON FOR APPLYING THE SCIENCE OF VISCOSITY:
(1) Will influence the perception of consumer:
(a) e.g.: ‘KAYA’ Cannot be too dilute, viscose is the best.
(b) e.g.: SAUCE Must be in certain value of viscosity.
(c) e.g.: JUICES Need to be diluted, not viscose.
(2) Easy to transport:
(a) e.g.: For transporting the liquid food to the other location
in the factory.
(3) Easy for gripping (adhesion) :
(a) e.g.: Adhesion of coated flour to the chicken meat.
(b) e.g.: Adhesion to the container or wrapper.
8. Load and Response
Stress
force per
unit area
Strain
deformation
○amount of
deformation
divided by
original length
9. Movement of FLUID will occur if the STRESS (TEGASAN) is given.
STRESS/PRESSURE = Force (N)/Area (m2
)
If the FORCE (N) is perpendicular (at 90o
angle) with surface It is
called NORMAL STRESS (Tegasan Normal).
Normally, it is called = PRESSURE (P)
If the FORCE is HORIZONTAL/PARALLEL (1800
) with the surface
It is called SHEAR STRESS (Tegasan Ricihan).
Different materials will give different effect of the SHEAR STRESS.
P3P2P1
(Force) F1 = N (V 0 to A)
V 0 = m/s
Fluid
∆ r (distance of the fluid movement), m
Viscosity (µ) = Pa.s OR kg/m.s
V A = m/s
10. VISCOSITY, µ (Kelikatan) = “resistance (rintangan) of
GASSES OR FLUIDS towards the flow of the SHEAR
STRESS”.
When STRESS is applied Fluids will move.
SO, STRESS (F/A); VELOCITY (m/s).
Fluids is assumed to be combination of FLUID LAYERS.
When the lower layer is given the STRESS, it will effect the
upper layer.
USUALLY, viscosity of lower layer > upper layer.
Each layer will move at different velocity (m/s).
The far the layer from the source of STRESS, the velocity
(m/s) of that layer.
Upper layer has < velocity (m/s).
The subsequent layer has > velocity (m/s).
11. The English unit for VISCOSITY are called “Poise” or
“centipoise” (cp) = g/cm.s
The SI UNIT for VISCOSITY Pa.s ( N.s/m2
OR kg/m.s)
1 cp = 1 × 10-3
kg/m.s =
1 × 10-3
Pa.s = 1 × 10-3
N.s/m2
(SI Unit)
1 cp = 0.01 poise = 0.01
g/cm.s (English Unit)
12. (1) For ELASTIC SOLID when the shear stress is applied, it
will change accordingly to the flow of the stress.
The material will RETURN BACK to its normal size when
the stress is removed. e.g.: rubber materials.
(2) For SOLID that have a plastic properties when the
SHEAR STRESS is applied, it will change accordingly to the
flow of the stress.
BUT = it will not come back to its original shape right after
the stress is removed. e.g.: jelly (agar-agar).
(3) For FLUIDS when the SHEAR STRESS is applied, it will
change accordingly to the flow of the stress.
This material will not come back to its original shape & will
moving towards the flow of the stress.
13. A shear stress, is
applied to the top of
the square while the
bottom is held in place.
This stress results in a
strain, or deformation,
changing the square
into a parallelogram.
17. Linear Strain
Occurs as a result of a change in the
object’s length.
Shear Strain
Occurs with a change in orientation of
adjacent molecules as a result of these
molecules slipping past each other.
19. Two Categories of
Flow & Deformation
Newtonian (Newtonian Law of Flow)Newtonian (Newtonian Law of Flow)
“the higher the viscosity of a liquid, the greater
is the force per unit area (shearing stress)
required to produce a certain rate of shear”
Shear – as a stress which is applied parallel or
tangential to a face of a material, as opposed to
a normal stress which is applied
perpendicularly.
Shear stress
Measured in (SI unit): pascal
Commonly used symbols: τ
Expressed in other quantities: τ = F / A
20. Two Categories of
Flow & Deformation
Newtonian (Newtonian Law of Flow)Newtonian (Newtonian Law of Flow)
A Newtonian fluid (named for Isaac Newton) is a
fluid whose stress versus rate of strain curve is linear
and passes through the origin. The constant of
proportionality is known as the viscosity.
A simple equation to describe Newtonian fluid
behavior is where
• τ is the shear stress exerted by the fluid ("drag") [Pa]
• μ is the fluid viscosity - a constant of proportionality [Pa·s]
• du is the velocity gradient perpendicular to the direction
dy of shear [s−1]
21. Two Categories of
Flow & Deformation
Newtonian (Newtonian Law of Flow)Newtonian (Newtonian Law of Flow)
In common terms, this means the fluid continues to
flow, regardless of the forces acting on it. For
example, water is Newtonian, because it continues to
exemplify fluid properties no matter how fast it is
stirred or mixed.
For a Newtonian fluid, the viscosity, by definition,
depends only on temperature and pressure (and also
the chemical composition of the fluid if the fluid is not
a pure substance), not on the forces acting upon it.
22. Two Categories of
Flow & Deformation
Newtonian (Newtonian Law of Flow)Newtonian (Newtonian Law of Flow)
For a Newtonian fluid, the viscosity, by definition,
depends only on temperature and pressure (and also
the chemical composition of the fluid if the fluid is not
a pure substance), not on the forces acting upon it.
If the fluid is incompressible and viscosity is constant
across the fluid, the equation governing the shear
stress is expressed in the
Cartesian coordinate system
23. Two Categories of
Flow & Deformation
Newtonian (Newtonian Law of Flow)Newtonian (Newtonian Law of Flow)
Cartesian coordinate system
where, by the convention of tensor notation,
• τij is the shear stress on the ith face of a fluid element in
the jth direction
• ui is the velocity in the ith direction
• xj is the jth direction coordinate
24. Two Categories of
Flow & Deformation
Newtonian (Newtonian Law of Flow)Newtonian (Newtonian Law of Flow)
Cartesian coordinate system
Tensor - are geometrical entities introduced into
mathematics and physics to extend the notion of
scalars, (geometric) vectors, and matrices
- Components of stress, a second-order tensor, in
three dimensions. The tensor in the image is the
row vector, of the forces acting on the X, Y, and
Z faces of the cube. Those forces are represented
by column vectors. The row and column vectors
that make up the tensor can be represented
together by a matrix.
25. Two Categories of
Flow & Deformation
Non-NewtonianNon-Newtonian
AA non-Newtonian fluidnon-Newtonian fluid is ais a fluidfluid whose flowwhose flow
properties are not described by a single constantproperties are not described by a single constant
value ofvalue of viscosityviscosity..
Many polymer solutions and molten polymers are
non-Newtonian fluids, as are many commonly found
substances such as ketchup, starch suspensions,
paint, blood and shampoo.
In a Newtonian fluid, the relation between the
shear stress and the strain rate is linear (and if one
were to plot this relationship, it would pass through
the origin), the constant of proportionality being the
coefficient of viscosity.
26. Two Categories of
Flow & Deformation
Non-NewtonianNon-Newtonian
A In a non-Newtonian fluid, the relation between theA In a non-Newtonian fluid, the relation between the
shear stressshear stress and theand the strain ratestrain rate is nonlinear, and canis nonlinear, and can
even be time-dependent. Therefore a constanteven be time-dependent. Therefore a constant
coefficient of viscosity cannot be defined.coefficient of viscosity cannot be defined.
A ratio between shear stress and rate of strain (or
shear-dependent viscosity) can be defined, this
concept being more useful for fluids without time-
dependent behavior.
28. Two Categories of
Flow & Deformation
Non-Newtonian ExamplesNon-Newtonian Examples
An inexpensive, non-toxic example of a non-
Newtonian fluid is a suspension of starch (e.g.
cornflour) in water, sometimes called oobleck
(uncooked imitation custard, being a suspension of
primarily cornflour, has the same properties).
The sudden application of force — for example:
by stabbing the surface with a finger, or rapidly inverting the
container holding it — leads to the fluid behaving like a solid rather
than a liquid.
This is the "shear thickening" property of this non-Newtonian
fluid. More gentle treatment, such as slowly inserting a spoon, will
leave it in its liquid state.
Trying to jerk the spoon back out again, however, will trigger the
return of the temporary solid state.
A person moving quickly and applying sufficient force with their
feet can literally walk across such a liquid.
29. Two Categories of
Flow & Deformation
Non-Newtonian ExamplesNon-Newtonian Examples
There are fluids which have a linear shear
stress/shear strain relationship which require a finite
yield stress before they begin to flow. That is the
shear stress, shear strain curve doesn't pass through
the origin.
These fluids are called
1. Bingham plastics.
clay suspensions, drilling mud, toothpaste, mayonnaise,
chocolate, and mustard. The classic case is ketchup which
will not come out of the bottle until you stress it by shaking.
30. Two Categories of
Flow & Deformation
Non-Newtonian ExamplesNon-Newtonian Examples
These fluids are called
1. Pseudoplastic Flow
Polymers in solutions such as tragacant, sodium alginate,
methylcellulose
Viscosity decreases with an increase in shear thinning
Caused by the re-alignment of polymer and/or the release
of solvents associated with the polymers
2. Dilatant Flow
Volume increases when sheared
Shear thickening
Suspension containing high-concentration of small
deflocculated particles
31. Two Categories of
Flow & Deformation
Non-Newtonian ExamplesNon-Newtonian Examples
There are also fluids whose strain rate is a function
of time. Fluids that require a gradually increasing
shear stress to maintain a constant strain rate are
referred to as rheopectic.
An opposite case of this, is a fluid that thins out with
time and requires a decreasing stress to maintain a
constant strain rate (thixotropic).
32. THIXOTROPY
is the property of some non-Newtonian
pseudoplastic fluids to show a time-dependent
change in viscosity; the longer the fluid
undergoes shear stress, the lower its viscosity.
A thixotropic fluid is a fluid which takes a finite
time to attain equilibrium viscosity when
introduced to a step change in shear rate.
the term is sometimes applied to pseudoplastic
fluids without a viscosity/time component.
Many gels and colloids are thixotropic
materials, exhibiting a stable form at rest but
becoming fluid when agitated.
33. THIXOTROPY
pseudoplastic fluids
○ Shear thinning is an effect where viscosity
decreases with increasing rate of shear stress.
Materials that exhibit shear thinning are called
pseudoplastic.
○ This property is found in certain complex solutions,
such as lava, ketchup, whipped cream, blood,
paint, and nail polish.
○ Pseudoplasticity can be demonstrated by the
manner in which shaking a bottle of ketchup
causes the contents to undergo an unpredictable
change in viscosity. The force causes it to go from
being thick like honey to flowing like water.
○ thixotropic fluid viscosity decreases over time at a
constant shear rate.
34. THIXOTROPY
The distinction between a thixotropic fluid
and a shear thinning fluid:
○ A thixotropic fluid displays a decrease in
viscosity over time at a constant shear rate.
○ A shear thinning fluid displays decreasing
viscosity with increasing shear rate.
○ Some fluids are anti-thixotropic: constant
shear stress for a time causes an increase in
viscosity or even solidification. Constant shear
stress can be applied by shaking or mixing.
Fluids which exhibit this property are usually
called rheopectic. They are much less
common.
35. IDENTIFICATION OF FLUIDS
RHEOLOGY USING VISCOMETER
RHEOLOGY “The science of the flow and deformation
(pembentukan) of fluids”.
2 types of measurement equipment :
(1) Rotational Type Viscometer (Viskometer Jenis Putaran):
Concentric cylinder (silinder konsentrik/berpusat sama).
UKM: known as ---- “Wide-gap rotational viscometer
with
spindle cylinder”
Parallel plate (plat selari).
Cone & plate (kon & plat).
Mixer (pengacau).
(2) Tube Type Viscometer (Viskometer Jenis Tiub):
Glass capillary (kapillari kaca).
Pipe (paip).
High pressure capillary (kapilari tekanan tinggi).
40. The most common type of equipment concentric cylinder
viscometer (viskometer silinder konsentrik).
Consisted with 2 concentric cylinder (silinder berpusat sama).
Fluid substances is put between 2 cylinders (INTERNAL &
EXTERNAL CYLINDER) .
INTERNAL CYLINDER (spindle) will spin & gives SHEAR
FORCE to the fluid substances.
There are particular sizes of SPINDLE can be found
depending on the viscosity of the fluid substances (make a
visual interpretation before selecting the sizes of spindle).
Resistance towards the flow will be experienced by SPINDLE &
it will measured the resistance.
The measured values will be multiply with CERTAIN
CONVERSION FACTOR for obtaining the “ACTUAL
VISCOSITY”.
41. The CONVERSION FACTOR is different according to the
SIZE of the SPINDLE & SPIN SPEED.
The example of viscometer brand: “Brookefield Viscometer”
CALCULATION EXAMPLES:
Spindle = No. 2
Spindle speed (N) = 60 rpm
CF = 5
Reading from the device = 64
∴ Viscosity (µapp:Non-newtonian OR µNewtonian) : 64 x 5 = 320 cp
Spindle : No. 3; Spindle speed (N) = 6 rpm; CF = 200
Reading from the device = 64.4
∴ (µapp:Non-newtonian OR µNewtonian) : 64.4 x 200
= 12,880 cp
42. NEWTONIAN FLUIDS:
ROTATIONAL VISCOMETER
For NEWTONIAN FLUID it will give actual value of
viscosity (µ).
n (flow behavior index) for NEWTONIAN = 1.0 and Plot
graph Log τ vs. Log γ.
PLOT FROM ORIGIN (0,0) ------ SLOPE = Actual viscosity
(µ)
SHEAR STRESS; τ (N.m2
) α torque (N.m) ------- (1)
SHEAR RATE; γ (s-1
) α N (spindle speed, rpm) -- (2)
(µ) =
slope
(τ)
(γ)
43. The SHEAR RATE (γ) at the surface of the spindle for NEWTONIAN
FLUIDS is as follows with n = 1:
4πN/1 - (Rb/Rc)2
Where: (a) Rb - radius of the spindle, m
(b) Rc - radius of the outer cylinder or container, m
(c) ω - angular velocity of the spindle, rad/s
ω = 2πN/60 ,when N is the RPM
The SHEAR STRESS (τ) at the wall of the spindle:
τ = A/2πLRb
2
γ =
Where:
A = Torque (N.m)
L = Height of the spindle, m
Rb = radius of the spindle, m
=
44. VARIOUS SPECIAL CASES CAN BE DERIVED FROM EQUATION (1):
(1) VERY LARGE GAP (Rb/Rc < 0.1) = This is the case of a spindle
immersed in a large beaker of test fluid. [ω = 2πN/60 ,when N is the RPM]
Test fluid
Rb Rc
Spindle
Container or cylinder
γ = = 4πN/n
45. VARIOUS SPECIAL CASES CAN BE DERIVED FROM EQUATION (1):
(1) VERY NARROW GAP (Rb/Rc > 0.99) = This is similar to flow parallel
plates. Taking the shear rate at radius (Rb + Rc)/2.
[ω = 2πN/60 ,when N is the RPM]
Test fluid
Rb
RcSpindle
Container or cylinder
γ =
46. EXAMPLE (NON-NEWTONIAN):
Rotational Type Viscometer Concentric cylinder (Wide-gap rotational
viscometer with spindle):
A wide-gap rotational viscometer with a spring constant of 7,187 dynes.cm are
used to measure a viscosity (cps; %) of a tomato sauce. The outer radius (Rc),
spindle radius(Rb)and height (L) of cylindrical spindle are 2.70 cm, 0.15 cm and
5.0 cm respectively. Determine the K and n? Calculate also the apparent
viscosity (µapp) of tomato sauce in N.s/m2
at spindle speed of 35 rpm.
Measurement values are given below:
Spindle speed (N) Device reading; cps (% scale)
20 rpm 29
50 rpm 44
100 rpm 60
47. Spindle cylinder
Test fluid - Tomato sauce
Beaker
“Wide-gap rotational viscometer with spindle cylinder”
L
RcRb
48. ANS:
Rb/Rc = 0.15 cm/2.7 cm = 0.055 < 0.1 --- So, equation very large gap is
used
n value determination:
(1) Sauce tomato = NON-NEWTONIAN FLUIDS
(2) Firstly, we have to construct a graph of ---- Log torque vs.
Log N
(3) Convert: Device reading; cps (%) Torque (dynes.cm)
Torque (dynes.cm) = Device reading; cps (%) × spring constant
(7,187 dynes.cm)
e.g.: Torque (dynes.cm) = 29/100 × 7187 = 2,084.23
(4) Convert: {dynes.cm} {N.m} by using the conversion
factor:
CONVERSION FACTOR: (1 dynes = 10-5
Newton)
e.g.: 2084.23 dynes.cm 10-5
N 1 m = 0.000208 N.m
1 dynes 100 cm
(5) Log (N) rpm ---- “see table”
50. (7) So, we have the LINEAR equation:
y = 0.451x - 4.268 -------- n value is the SLOPE
∴n = 0.451 (n < 1.0 = PSEUDOPLASTICS FLUIDS)
K value determination:
(1) Convert: Torque (N.m) τ (N/m2
) by using the formula:
τ = A/2πLRb
2
; A = Torque (N.m)
e.g.: τ = 0.000208/[2 × 3.14 × 5.0/100 × (0.15/100)2
] =
294.62 N/m2
(2) Log τ ------- ‘see table’
(3) Convert: N (rpm) γ (s-1
) by using the formula:
γ = 4πN/n
e.g.: γ = [4 × 3.14 × (20 rpm/60 s)]/0.451 = 9.26 s-1