FINITE-ELEMENT MODELING OF NONISOTHERMAL VISCOMETRIC FLOWS IN RUBBER MIXING

Attempts to find a general viscoelastic fluid model which would be app licable to all different classes of flow problems and could produce ex perimentally verifiable results, have so far failed. Instead efforts h ave been concentrated in finding a suitable viscoelastic model for the particular class of flow problem in hand. Bearing this in mind, a sim ple viscoelastic fluid model which has shown promising results for cas es where there is a dominant flow direction (i.e. the flow is viscomet ric) is considered here. Such conditions may occur inside a rubber mix er where in cylindrical coordinate system (r,theta,z), the elastomer i s flowing dominantly in theta direction. This paper deals with the Gal erkin finite element modelling of viscometric flows under non-isotherm al conditions. The novel aspect of this work is the extension of the a pplication of a viscometric constitutive equation known as (CEF) model to the simulation of predominantly circumferential flow in a two-dime nsional representation of an internal mixer using polar coordinates. F or a given set of boundary conditions, the mathematical model can simu late the velocity, pressure and temperature fields inside a mixer. Com parison of the numerical results with the available experimental evide nce confirm the general validity of the mathematical model used.