Structrue Design And Theoritical Calculation Of Polymer Melt Cooler

The polymer melt cooler is applied to the polymer extrusion foaming production line. Its application purpose is to cool the polymer melt to the most suitable foaming temperature before it entering into the foaming die. Because of its heat exchange area in unit volume is large, it can accurately control the melt temperature. The melt cooler device structure is simple and it could be easily assembled or disassembled. In virtue of having these advantages, it has attracted much attention in the field of polymer foam. But due to the melt cooler structure needs to adapt to the complex flow character of the polymer melt in heat transfer process, it has yet to achieve the large-scale application in the industrial production. Application of the polymer melt cooler can simplify the foaming production line, greatly shorten the production cycle, and optimize the quality of foam products. Its advantage is very obvious, but now exclusively used for high viscosity melt cooling equipment is less, so the research of technologies for the design and development of polymer melt cooler has great significance in the polymer extrusion foaming field.According to the polymer melt has characteristics of high viscosity and low flow rate in the foaming process, in this paper, a melt cooler with porous heat transfer inner core was developed. The theoretical calculation and structural design of the melt cooler is based on the polymer melt heat demand, technological conditions and convective heat transfer theory. To simplify the design calculation process, the Visual Basic 6.0 visual programming language was used to develop the calculation program, in order to serializing the calculate process. By using the program, the influence of structural parameters on the heat transfer performance of the melt cooler was analysed.To study the thermal uniformity and pressure drop of the internal flow field of the polymer melt in the device, the fluid flow analysis software POLYFLOW was used to simulate the flow process of polymer melt when it flow through from the inlet to the outlet of the melt cooler. By analyzing the simulation results, it was found that, the polymer melt temperature in the flow direction has uniformly downward trend, and with temperature decreasing, the viscosity of the melt is increasing. And comparing the Temperature field and melt pressure drop in the three kinds of porous type heat exchange core, it was noticed that with the increasement of the number of hole groups, the melt flow diameter decreases, the heat exchange area is enlarged, the melt heat transfer rate is more rapid, the temperature difference between outlet section is smaller and the melt pressure drop is higher.Based on the existing twin screw extrusion machine production line in the laboratory, using the melt cooler which was designed and developed in this paper, temperature and pressure measuring platform was build up to complete the final extrusion foaming experiment. To verify the correctness of the theoretical calculation results and simulation results, the thermal efficiency and polymer melt pressure drop experimental data of the melt cooler with three heat exchange core which have different structure parameters was compared. In this paper, the application of the comprehensive evaluation index of melt cooler evaluation, provided a theoretical basis for optimal design.