In this paper, penalty finite element method is applied to the simulation of
three-dimensional incompressible viscous steady flow, and the program is coded for analysis of
three-dimensional flow process of plastic melt in extrusion die. Slit die is typical in polymer
extrusion process, and the relevant part is used widely. Because the flow law is different for various
polymers with different rheological character even in the same die, the polymer flow in slit die is
simulated for Newtonian fluid and power-law fluid by the program and ANSYS, respectively. Flow
laws of two kinds of fluid are compared, and the result shows that the non-uniform velocity
distribution in outlet is caused by the non-Newtonian effect of material. The penalty factor is
important for the penalty finite element model, which decides the precision and efficiency to a great
extent. The proper penalty value is decided by some factors, for example, the character of the whole
equations and geometric model. Numerical solution with change of penalty value and viscosity is
analyzed, and the result shows that the penalty value should be suited with viscosity in special range
for penalty finite element model. The experiment has been developed, and the velocity distribution
in outlet of slit die is measured. The result of finite element analysis is consistent with experimental
result basically, and the reason of result divergence of the two ways is analyzed. The results show
that the given model is suited for the polymer extrusion process, and the advice of the selection of
penalty value is instructional for penalty element model.
Three Dimensional Flow Velocity of Reservoir Calculated with the Data of Temperature Distribution.
