Numerical simulation analysis of factors affecting filling unbalance based on convective mixing at microscale

Abstract

Aiming at the new control method of filling unbalance in the flow channel by using convection mixing， the influence of micro-scale polymer melt flow factors on the control characteristics of melt temperature distribution in the flow channel was studied by numerical simulation. Taking the "H" flow channel as the research object， the convection mixing device was arranged in the flow channel. The effects of melt temperature， convective heat transfer coefficient and flow channel size on melt filling unbalance were studied by single factor experiment. The numerical simulation results show that， the increase in melt temperature is accompanied by the decrease of melt self-viscosity under adiabatic boundary conditions. The temperature difference between symmetric points decreases， which improves the filling imbalance. Under the convective heat transfer boundary， the increase of melt temperature increases the heat loss of melt through the wall， and the increase of temperature difference between symmetric points leads to the more obvious filling imbalance. The lower the convective heat transfer coefficient， the lower the thermal conductivity efficiency between melt and wall， and the higher the average melt temperature， which increases the temperature difference between symmetric points and intensifies the filling imbalance. With the decrease in the size of the flow path， the micro-scale effect is weakened， the temperature difference between symmetric points can be reduced， and the phenomenon of filling imbalance is better improved. The convective heat transfer coefficient has the greatest influence on the filling unbalance， followed by the flow channel size， and finally the melt temperature.

Keywords

• convective mixing
• melt temperature
• convective heat transfer coefficient
• runner system
• unbalance of packing