Numerical Analysis on Influence Factors of Conical Convergent Flow Field Distribution of Polymer Melt
REN Zhong1,2, HUANG Xing-yuan1, LIU He-sheng1
1. Polymer Processing Research Laboratory, Nanchang University, Nanchang 330031, China;
2. Key Laboratory of Optic-electronic and Communication, Jiangxi Science and Technology Normal University, Nanchang 330038, China
Abstract：To interpret the effect of multiple factors on pressure, velocity and shear rate distribution of polymer melt extrusion at entrance and exit of the die, a conical die structure and the finite element mesh model were established based on the basic equation of entrance convergent flow, and material parameters, process parameters and die shapes were considered via the numerical simulation and finite element method(FEM). In the FEM, Cross constitute equation, wall no-slip model were employed, and some FEM computing methods, e.g., quadratic interpolation of velocity, linear interpolation of pressure and viscosity Newton iteration algorithm were used for the generalized isothermal flow melt. The results show that the pressure distribution is directly related with the melt viscosity, flow index, relaxation time, entrance flow rate, and channel compression ratio etc, and the normal velocity and shear rate is mainly affected by the entrance flow rate. The quantitative analysis of multiple factors shows that the pressure increases with the increasing of melt viscosity, entrance flow rate and channel compression ratio, but decreases with the increasing of the flow index and relaxation time, and the normal velocity and shear rate increase with the increasing of the flow rate. These factors make the die exit pressure, normal velocity and shear rate not to be zero, thus lead to problems including die swell and etc.
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REN Zhong, HUANG Xing-yuan, LIU He-sheng. Numerical Analysis on Influence Factors of Conical Convergent Flow Field Distribution of Polymer Melt. Journal of Materials Engineering, 2016, 44(3): 52-59.
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