Unsteady Heat Transfer and Fluid Mechanism at Melt-Front Region with Injection Molding with High Polymer Materials

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In the melting process of high-polymer materials on the industrial advantage, there are several characteristic behaviors in the flow and heat transfer field in depends on its non-newtonian properties and non-liner temperature dependencies. These flow and heat transfer behaviors become more important recently to keep and control engineering quality and speed in the material processing. For the modeling of heat-fluid phenomena, the experimental investigation of the melting high-polymer flow has been done with various method measurements for getting the time-special flow and heat transfer properties and its unsteady effects.In this study, the unsteady flow and heat transfer phenomena in melt-front of high-polymer are shown experimentally with visualization images analysis and multi-point unsteady measurements. The unsteady geographic shape of the gas-liquid interface and velocity vector field in melt-front region, which make important effects on whole flow and heat transfer field, are det … More ected for making clear the heat-fluid 3-D phenomena from the continuous images by high-speed video system. The unsteady and local efficiencies of the shape configuration on interface are analyzed numerically by cross-correlation between various positions for the detection of the transitional phenomena.The high-polymer materials ( PP ) are put into the cylindrical tube with many solid original short bars, hi the tube, flie material changes its phase aspect in transit by electric heaters. The melting fluid gets pushed out into the glass tube ( test section: various types ) from the nozzle by a piston moved with controllable stepping motor. The surfaces of tube are set normal and artificial conditions with thin-layer of silicon oil for comparison. The velocity conditions at exit are changed as the moving velocity of pushed piston for making clear its effects.From experimental results, several interesting phenomena were detected as below. The gas-liquid interface changes its shape properties time-dependently, and the two-way transitions of phenomena are detected with the local configuration analysis, which mean that one is from the center to wall ( fountain flow ), another is from near-wall to center by non-uniform slipping phenomena near-wall. Heat transfers in melt-front are also changed and correlated with the above phenomena. These phenomena originated in high-polymer properties can be made needful of building the heat transfer mechanism models on numerical simulations. Less