Some finite elements studies of extrusion

TLDR: For non-Newtonian fluids of the power-law type, where the viscosity is an exponential function of the temperature, increasing the exponential coefficient α (or decreasing the Peclet number Pe) causes an increase in ϵ when the power law index n and the modified Brinkman number Br are kept fixed as mentioned in this paper.

Abstract: Some finite element results of the non-isothermal extrusion process are presented. For Newtonian fluids, increasing the Nahme-Griffith number Na is found to increase the swelling ratio ϵ. The temperature distribution near the exit plane is shown to be a critical factor determining whether the extrudate would swell or contract relative to the isothermal, Newtonian case. In this waya recent theory by Tanner has been partly verified. For non-Newtonian fluids of the power-law type, where the viscosity is an exponential function of the temperature, increasing the exponential coefficient α (or decreasing the Peclet number Pe causes an increase in ϵ when the power-law index n and the (modified) Brinkman number Br are kept fixed. However, the effects are small for shear-thinning fluids (n<1), but become stronger as n increases. On the other hand, at fixed (Br) and (Pe) (thus fixing α) increasing n causes rapid increases in ϵ