螺槽内塑料熔体传热及温度的数值模拟

Numerical Study of Heat Transfer and Temperature in the Screw Groove for Molten Plastic

用数值方法模拟塑料加工过程中的熔体可以了解其流动与传热历史,进而提高塑化性能,改善制品质量。针对熔融塑料在螺槽中的流动与传热,结合运动方程和本构方程,建立多因素同时作用下的能量守恒数学模型,模型通过热对流项、热传导项、黏性耗散热项的共同作用描述传热与温度分布的动态过程和稳定状态特性。利用有限差分法离散偏微分方程,构造线性方程组,根据初始条件和边界条件,并借助数值计算方法,求解得到三维流道的温度模拟结果。分析模拟结果,得到螺槽内塑料熔体的温度、热对流、热传导、黏性耗散热的分布及变化规律,据此可以更深入地理解塑化过程及其影响因素。在同样条件下比较,模拟结果与商品化软件的计算结果是一致的,验证了所提方法的正确性。

The numerical simulation can help understanding the melt flow and heat transfer history while plastic processing process in the screw groove, and improve plasticizing performance and the product quality. According to the situation of molten plastic flow and heat transfer in the screw groove, combined with motion equations and constitutive equation, the energy conservation mathematical model is established in which multiple factors are taken into account. The joint action of the heat conduction, convection, and viscous dissipation in the model describes the heat transfer and the temperature distribution characteristics of dynamic process and stable state. Using finite difference method discrete partial differential equations, and construct linear equations. After the equations had been solved by numerical calculation method within the initial condition and boundary conditions, the temperature results of the three-dimensional flow field are worked out. Analysis of simulation results, get the distribution and change rules of temperature, heat convection, heat transfer, viscous dissipation of heat in screw groove plastic melt, thus can be more in-depth understanding of plasticizing process and its influencing factors. Comparison under the same conditions, the simulation results with the calculation results of commercial software is consistent, verified the validity of the proposed method.