Numerical analysis and experimental investigation of three dimensional polymer melt flows in injection molding

In this thesis study, three dimensional flow behaviour of the molten polymer in the mould cavity during the injection moulding is visually recorded and numerically analysed. In this study, which includes the Low Density Polyethylene (LDPE), High Density Polyethylene (HDPE) and Polystyrene (PS) as polymer, the three dimensional flow behaviour in the mould cavity, is become visually recordable by tempered three glasses located into the mould cavity. Images are recorded by a video camera and the frames are obtained from the records. Numerical analyses are reached by using the FLUENT software. To obtain the more realistic results from the analysis, the physical and the rheological properties of the LDPE, HDPE and PS are experimentally obtained and the obtained data are modelled and the models are taken into account in the governing equations. Viscosity is expressed depending on the shear rate and the temperature; the density and the thermal conductivity are expressed depending on the temperature. In the analyses, where the pressure based solution algorithm is preferred, the pressure is obtained with the SIMPLE algorithm. The flow front is determined according to the volume of fluid (VOF) method. The analyses result which includes the constant physical and rheological properties and the analyses result which includes the physical and rheological property models are compared with the experimental images. It is obtained that the flow front profiles are the same with each other but, if the filling times are considered, the analysis results obtained using the physical and rheological property models are more realistic.