Skip to main content
Log in

Flow birefringence of polymer melts: Calculation of velocity and temperature profiles in a cone-and-plate apparatus

  • Published:
Rheologica Acta Aims and scope Submit manuscript

Summary

In this paper an analysis is given of the shear flow which occurs in a closed cone-and-plate rheometer, as is used for the measurement of the flow birefringence of polymer melts. The influences of shear rate and temperature on the fluid viscosity are taken into account by the use of a relation which combines the concept of the inelastic “power law fluid” with that of an exponential temperature dependence. Velocity and temperature profiles are calculated. Among other things it is shown, how viscous dissipation can disturb the flow field.

Zusammenfassung

In der vorliegenden Arbeit wird die Scherströmung analysiert, die in einem zur Messung der Strömungsdoppelbrechung polymerer Schmelzen dienenden geschlossenen Kegel-Platte-Rheometer auftritt. Die Abhängigkeit der Viskosität von der Schergeschwindigkeit und der Temperatur wird mit Hilfe einer Beziehung berücksichtigt, die das Modell der unelastischen Ostwald-De Waele-Flüssigkeit mit einer exponentiellen Temperatur-Abhängigkeit verbindet. Geschwindigkeits-und Temperaturprofile werden berechnet. Unter anderem wird gezeigt, wie die viskose Dissipation das Geschwindigkeitsfeld stören kann.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

Abbreviations

1:

unity tensor

b :

parameter describing the temperature dependence of viscosity

C p :

heat capacity at constant pressure

D, D ij :

rate of strain tensor

D/Dt :

substantial derivative

E a :

apparent flow activation energy

g :

gravitational acceleration

Gr:

Griffith number

I 1 :

first invariant of the rate of strain tensor

I 2 :

second invariant of the rate of strain tensor

I 3 :

third invariant of the rate of strain tensor

k :

thermal conductivity

n φ :

unit vector tangential to the linesψ andr = constant

n ψ :

unit vector tangential to the linesφ andr = constant

n r :

unit vector in the direction of the linesφ andψ = constant

p :

undetermined hydrostatic pressure

p :

stress tensor

q n :

nominal shear rate

q φψ, qφr :

velocity gradients

r :

radius

R :

gas constant

R i :

inner radius of the ringshaped test channel

R 0 :

outer radius of the ringshaped test channel

t :

time

T :

temperature

T R :

reference temperature

ΔT :

temperature differenceT− TR

V :

mass average velocity

V r, Vθ, Vφ :

components of velocity vector

α :

dimensionless parameter describing the shear rate dependence of the viscosity

ε :

normalized gap angleψ/ψ m

η 1 :

constant in power law

θ :

spherical coordinate, co-latitude

ρ :

dimensionless radiusr/R 0

ρ 0 :

mass per unit of volume

φ :

spherical coordinate, azimuthal angle

Φ :

dimensionless temperature

ψ :

angleψ = π/2 − θ (latitude)

ψ :

gap angle

ω :

angular velocity

ω r :

angular velocity of rotating plate

Ω :

dimensionless angular velocityω/ω r

:

the nabla operator

References

  1. Wales, J. L. S., The Application of Flow Birefringence to Rheological Studies of Polymer Melts, Monograph (Delft 1976).

  2. Wales, J. L. S., H. Janeschitz-Kriegl J. Polymer Sci.5, 781 (1967).

    Google Scholar 

  3. McKelvey, J. M., Polymer Processing, p. 99 (New York-London 1962).

  4. Gortemaker, F. H., M. G. Hansen, B. de Cindio, H. Janeschitz-Kriegl Rheol. Acta15, 242 (1976).

    Google Scholar 

  5. Hennig, J., W. Knappe, P. Lohe Kolloid Z.189, 114 (1963).

    Google Scholar 

  6. Lohe, P. Kolloid Z.205, 1 (1965).

    Google Scholar 

  7. Ostwald, W. Kolloid Z.36, 99 (1925).

    Google Scholar 

  8. Ref. (3), p. 41.

  9. Staverman, A. J., F. R. Schwarzl, Chapter I in: Physik der Hochpolymeren, IV (Berlin 1956).

  10. Ferry, J. D., Viscoelastic Properties of Polymers, 2nd ed. (New York 1970).

  11. Gorissen, W. C. M., personal communication.

  12. Am. Soc. Testing Matls., Tests D-927 and D-1077.

  13. Griffith, R. M. Chem. Fund.1, 180 (1962).

    Google Scholar 

  14. Carnahan, B., H. A. Luther, J. O. Wilkes, Applied Numerical Methods (New York-London 1969).

Download references

Author information

Authors and Affiliations

Authors

Additional information

The present investigation has been carried out under the auspices of the Netherlands Organization for the Advancement of Pure Research (Z. W. O.).

On leave from University of Naples; Research Fellow, Delft University of Technology.

With 7 figures

Rights and permissions

Reprints and permissions

About this article

Cite this article

Gortemaker, F.H., de Cindio, B. & Janeschitz-Kriegl, H. Flow birefringence of polymer melts: Calculation of velocity and temperature profiles in a cone-and-plate apparatus. Rheol Acta 15, 479–486 (1976). https://doi.org/10.1007/BF01530350

Download citation

  • Received:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF01530350

Keywords

Navigation