Upload File

viscosity

4
In case, you do not see blue navigation panel at left, please click here and then locate this page on the blue navigation panel at left. SHEAR When forces act parallel to the surface area of the matter, internal stress (force / surface area) between adjacent layers of surface resist the relative movement of layers. SHEAR and SHEAR RATE:(Figure 601) With the application of force, if a layer moves with velocity V at a distance of r then Shear rate = V / r VISCOSITY: Viscosity is a way to describe how much resistance a fluid melted polymer exhibits when an attempt is made to make it flow. High viscosity means the melt is thick and resistance to flow is high. Low viscosity means resistance flow is less. Just as solid surfaces in contact exert frictional force on each other, the relative motion of layers of liquid is also restricted by friction. This internal resistance to flow existing between two liquid layers when they are moved relative to each other is called viscosity. Consider the flow of liquid through a pipe and imagine that liquid moves in layers. The liquid moves when there exists the pressure difference between the pipe ends. The liquid in the center of pipe would be moving with higher velocity than the liquid layer at the internal wall of the pipe. This is because the frictional forces act between the layers of liquid. Therefore there exists a velocity gradient between pipe wall and center of pipe. Such motion of liquid is known as laminar flow. The velocity of particles at a given distance from the center of motion is constant. If the layers intermix we get turbulent flow. A streamline is a curve whose tangent always lies along the direction of motion of fluid at that point. The streamlines never cross and in laminar flow they do not change with time. It is observed that frictional force is directly proportional to the product of

Upload: charles-perry

Post on 03-Oct-2015

6 views

Category:

Documents


3 download

Report

DESCRIPTION

zdf

TRANSCRIPT

  • 3/20/2015 Viscosity:

    http://www.pitfallsinmolding.com/shearviscosity.html 1/4

    Incase,youdonotseebluenavigationpanelatleft,pleaseclickhereandthenlocatethispageonthebluenavigationpanelatleft.

    SHEAR

    Whenforcesactparalleltothesurfaceareaofthematter,internalstress(force/surfacearea)betweenadjacentlayersofsurfaceresisttherelativemovementoflayers.

    SHEARandSHEARRATE:(Figure601)

    Withtheapplicationofforce,ifalayermoveswithvelocityVatadistanceofrthen

    Shearrate=V/r

    VISCOSITY:

    Viscosityisawaytodescribehowmuchresistanceafluidmeltedpolymerexhibitswhenanattemptismadetomakeitflow.Highviscositymeansthemeltisthickandresistancetoflowishigh.Lowviscositymeansresistanceflowisless.

    Justassolidsurfacesincontactexertfrictionalforceoneachother,therelativemotionoflayersofliquidisalsorestrictedbyfriction.Thisinternalresistancetoflowexistingbetweentwoliquidlayerswhentheyaremovedrelativetoeachotheriscalledviscosity.

    Considertheflowofliquidthroughapipeandimaginethatliquidmovesinlayers.Theliquidmoveswhenthereexiststhepressuredifferencebetweenthepipeends.Theliquidinthecenterofpipewouldbemovingwithhighervelocitythantheliquidlayerattheinternalwallofthepipe.Thisisbecausethefrictionalforcesactbetweenthelayersofliquid.Thereforethereexistsavelocitygradientbetweenpipewallandcenterofpipe.Suchmotionofliquidisknownaslaminarflow.Thevelocityofparticlesatagivendistancefromthecenterofmotionisconstant.Ifthelayersintermixwegetturbulentflow.

    Astreamlineisacurvewhosetangentalwaysliesalongthedirectionofmotionoffluidatthatpoint.Thestreamlinesnevercrossandinlaminarflowtheydonotchangewithtime.

    Itisobservedthatfrictionalforceisdirectlyproportionaltotheproductof

  • 3/20/2015 Viscosity:

    http://www.pitfallsinmolding.com/shearviscosity.html 2/4

    velocitygradientandcrosssectionalarea.

    F=Axvelocitygradient=Axdv/dr

    =coefficientofviscisity.A=crosssectionalarea.dv/dr=velocitygradient.

    TangentialstressesShearstress==VelocitygradientShearrateForcedistanceUnitsisx=Pascalsec.=Pas.Areadistance/sec.

    Viscosityvarieswithtemperature.

    Fluid Viscosity

    Pasat200C

    Fluid Viscosity

    Pasat200C

    Air 1.8x105 Blood 34x103

    Glycerol 8.3x101 Water 1x103

    CastsorOil 2.42 Mercury 1.5x103

    SHEARSTRESS/SHEARRATECURVE:(Figure602)

    Fromtheaboveplasticflowcurveitisobservedthattheviscosityreducesastheshearrateincreases.Differentpolymerswillexhibitdifferentcurveofthesamenature.

    SHEARTHININGatcompressionzoneofSCREW

  • 3/20/2015 Viscosity:

    http://www.pitfallsinmolding.com/shearviscosity.html 3/4

    ShearinginNozzle

  • 3/20/2015 Viscosity:

    http://www.pitfallsinmolding.com/shearviscosity.html 4/4

    HOME Contacttobuythisbook ThingstoknowProcess ThingstoknowPolymers ThingstoknowPartDesign ThingstoknowMould

    ThingstoknowMachine

    InjectionMouldingProcess

    ScrewPlasticating Moulding Keyfactorsinfluencingproces Shearstraincurve

    pvtdiagram Thermalstability BalancingmeltFlow BalancingHeat Freezing QualityProblems

    ThreeBalances MouldedinStress Shrinkage InconsistentDimension Sinkmark Weldlines

    MouldingProblems CYCLETIME PlasticsPartDesign FlowAnalysis .. ..

    EngineeringBasicsinMachine

    GlossaryoftechnicaltermsPhysics

    GlossaryoftechnicaltermsPolymerprocess

    Myth UnderstandingMouldCoolingChannels

    IdealMouldingShop


Magma viscosity

Viscosity Process

VISCOSITY SHEAR Newton’s law of viscosity f u

Viscosity Determinations

Gas Viscosity

PROCESS VISCOSITY On-line viscosity analyzers for ...pmip.cz/pdf/B1210.pdf · On-line viscosity analyzers for hydrocarbon and process applications. ... 7827 is unique digital viscosity

Viscosity & flow

Cream Viscosity

Viscosity - resources.saylor.org · Viscosity 5 Viscosity coefficients Viscosity coefficients can be defined in two ways: • Dynamic viscosity, also absolute viscosity, the more

Viscosity Classification Equivalents - Petroliance - General/Viscosity...Each ISO viscosity grade number corresponds to the mid-point of a viscosity range expressed in centistokes

Newton’s law of viscosity, • Pressure and temperature dependence of viscosity · 2021. 3. 16. · dependence of viscosity Viscosity of Newtonian fluids depends only on temperature

Elasticity and Viscosity ELASTICITY & VISCOSITY

viscosity - fuoyepedia.com.ng

Universal Viscosity Curve Theory - ftimeters.com · Universal Viscosity Curve Theory Turbine Flow Meters and Flow Viscosity TM

REVOLUTIONIZE yOUR ONLINE VISCOSITy MEASUREMENT … · 2019-01-17 · Fuel oil heat exchanger Fuel oil To engine Viscosity input Viscosity output Viscosity output Inline viscosity

Viscosity 080808

Viscosity measurements

Viscosity and Excess Viscosity for Associated Binary ... · Viscosity and Excess Viscosity for Associated Binary Mixtures at T= (298.15, 308.15 and 318.15) Arun K.Singh, ... Viscosities

Viscosity, viscosity factors, kinematic viscosity, viscometer, visccosity grade (ISO and SAE)

4. Viscosity

Viscosity of magmatic liquids: A model - eoas.ubc.cakrussell/VISCOSITY/grdViscosity_files/grd... · Viscosity of magmatic liquids: A model ... The viscosity of silicate melts controls

DIAGNÓSTICA - Viscosity

Chapter 2: Viscosity of Fluid. Chapter Objectives 1.Define dynamic viscosity. 2.Define kinematic viscosity. 3.Identify the units of viscosity. 4.Describe

Viscosity & Viscosity Modifiers · Viscosity Index (VI) defines the viscosity relationship with temperature. • The Viscosity of low VI oils change significantly with temperature

Viscosity PPT

S.D.M. VISCOSITY

Brookfield Viscosity

Viscosity Manual

Viscosity ofLiquids

Viscosity Measurement

VISCOSITY 'MEASUREMENT AND VISCOSITY INDEX.delibra.bg.polsl.pl/Content/16169/P-102_1943_No232.pdf · VISCOSITY MEASUREMENT AND VISCOSITY INDEX. 103 determining the kinematic viscosity

Viscosity determinations.pdf

VISCOSITY The measure of a fluid’s resistance to flow. High Viscosity – thick Low Viscosity - thin

01 Viscosity

VISCOSITY AND VISCOSITY MODIFIERS - Infineum Insight · VISCOSITY AND VISCOSITY MODIFIERS ... Water 1 Gasoline 0.5 ... • Viscosity is a measure of a fluid’s resistance to flow