振动力场作用下单螺杆塑化熔融过程数值模拟

Numerical Simulation of Melting Process in Single-Screw Extruder Under Vibration Force Field

为研究振动力场对单螺杆挤出机中熔融过程的影响,根据“流动的固体”这一概念,利用流体动力学实现对整个熔融区域的求解,解决了相变以及固熔界面跟踪的问题,建立了简化的二维动态熔融模型.由于熔融过程是一个非等温相变过程,并且振动力场作用下聚合物具有依时性非线性黏弹特性,因此修正了具有松弛谱特性的Maxwell非等温黏弹本构模型,对动态熔融过程进行了模拟,并分析了振动频率与振幅对熔融行为的影响规律.

In order to investigate the effect of vibration force field on the melting process in a single-screw extruder, a simplified 2D dynamic melting model is established by adopting the assumption of ＂flowing solid＂ and the theory of hydrokinetics to solve the problem in the whole melting region. Thus, the problems of phase change and the solid-melt interface track are successfully solved. Moreover, as the melting process is of a non-isothermal phase change and the polymer presents time-dependent nonlinear viscoelastic characteristics in vibration force field, a self-amended non-isothermal Maxwell viscoelastic constitutive model that reflects the relaxation time spectrum of the polymer is developed. The dynamic melting process is finally simulated, followed by the analysis of the effects of vibration frequency and amplitude on the melting process.