中文摘要：

模拟了幂律型流体在圆形截面过渡为正方形截面的收缩口模内的三维非等温挤出流动．采用罚有限元法处理了流体的不可压缩条件，消去了动量方程中的压力项，并运用降阶积分方法确保了压力解的稳定性；采用SUPG方法构造能量方程的非对称权函数，克服了对流项占优时数值解的失真；考虑了聚合物在口模内流动时产生的剪切热，运用Arrhenius模型计算了温度对黏度的影响．计算实例表明，可以获得合理的温度、压力、应力和温度分布．

英文摘要：

Finite element method is applied in the simulation of polymer extrusion in this paper. Penalty finite element method is used to solve the incompressible constraint and the pressure term in momentum equation is eliminated. For numerical integration in elemental level, the term with the penalty parameter is calculated using the reduced integration method to avoid the lock＇ with very big penalty parameter. By adopting Streamline Upwind/Petrov-Galerkin （SUPG） formulation for the selection of the unsymmetrical weight function for energy equation, the distortion of the numerical results was overcome when the convective term is dominant. With taking into account of the heat transformed from mechanical energy, the viscosity dependence with temperature is analyzed by Arrhenius model. The example shows that the model and methods presented in this paper can give suitable distributions of velocity, pressure, viscosity and temperature for polymer flowing in three-dimensional extrusion dies.