Highly filled rubber compounds exhibit a unique rheological
behavior, which is affected by its filler–filler and filler–matrix
interactions leading to pronounced nonlinear viscoelasticity.
The necessity to consider these characteristics in rheological
testing and modeling, adds further complexity providing
universally valid numerical descriptions. In the present
study, the pressure driven contraction and capillary flow of
a carbon black filled hydrogenated acrylonitrile–butadiene
rubber compound is studied both experimentally and
numerically. Rheological testing indicates no pronounced
slippage at the wall but a shear sensitive plug flow at
the centerline. The viscoelastic Kaye-Bernstein–Kearsley–
Zapas/Wagner, the viscoplastic Herschel–Bulkley and the
viscous power-law models are used in computational fluid
dynamic simulations aiming to predict measured pressure
drops in an orifice and various capillary dies. Viscoelastic
modeling is found of particular importance describing contraction
flow dominated areas, whereas viscous models are
able to predict pressure drops of capillary flows well.