Numerical Analysis Of Heat Transfer In Metering Zone During The High-Speed Extrusion

Improving extrusion high-speed is an important tendency for the development of modern extrusion processing technology. On one hand, high speed extrusion can prominently improve the output and satisfy the requirement of modern producing. On the other hand, by improving the control of the melt temperature, it can distinctly reduce the waste of energy, pull the cost down and enhance the efficiency of extrusion.High-speed extrusion is increasing the screw speed to gain the highoutput under guaranteeing the products' quality. The melt rheology isanalyzed by using the theory of melt conveying, and using the theory ofheat transfer analyzes the heat transfer in the high speed extrusion in detail.In the paper, the main contents were as follows:1.During the analysis for the liquid dynamics theory for the metering stage, the author calculated the velocity field and pressure field in the metering zone, applied differential equation to calculate the energy consumption.2.The melt temperature was analyzed by employing the Laplace transform method under the screw cooled or not. The melt temperature distribution was solved by the MathCAD programs.3.The numerical simulation of heat exchange was divided into fluid cooling and gas cooling. The shell-and-tube heat exchanger was taken as math model to analyze fluid cooling in metering zone. The gas cooling was taken for radiation heat transfer and convection heat transfer out of the tube. The MathCAD program is the auxiliary tool to analyze the scheme of controlling -temperature in the high-speed extrusion.4.After compared the three cooling types, the author draw theconclusion-when the PE is extruded by the 30 singlescrew extrude in the high speed, once the screw speed isabove ISOrpm, wind cooling can not fit the heat transfer, and once the screw is beyond the 250rpm, the oil cooling becomes invalid, finally only water cooling can be selected to transfer the heat.