NEW MELT CONVEYING MODELS FOR A SINGLE SCREW EXTRUDER¹

Abstract

The flow theory in an extruder is fundamental to the study of extrusion technology. Present analytical solutions of the flow theory used in many studies give significant overpredictions of the volumetric flow rate due to erroneous boundary conditions used. Modified flat plate models with and without considering side wall effect and a coaxial cylinder model for Newtonian fluids were derived in this study using new boundary conditions confirmed by Choo et al. (1980). Using experimental data from published literature, it was found that the volumetric flow rates in the extruder were better predicted by these models than the numerical solutions or the original analytical solutions.

Effect of Inclined Orifice in Air Impingement Freezer on Heat Transfer Characteristics of Steel Strip Surface

“…To facilitate the analysis of the heat transfer strength at different locations on the steel strip, lines A and B were considered on the surface of the strip (as in Figure 2) [28]. Line A corresponds to the line directly below the center of each row of nozzles; there are eight rows of nozzles in total, so they are lines A1, A2, .…”

Nghiên Cứu Dòng Chảy Của Nhựa Nóng Chảy Trong Thiết Bị Đùn Trục Vít Đơn

“…Độ chính xác của mô hình là trong phạm vi 25%, tuy nhiên mô hình quá phức tạp để ứng dụng vào thực tế. Tương tự như vậy, Y. Li và F.Hsiel [5] đã tự phát triển mô hình toán mới để tính toán dòng chảy của lưu chất Newton đẳng nhiệt và bất khả nén bên trong máy đùn trục vít đơn. Họ dùng tới 69 phương trình toán học để giải quyết vấn đề.…”

Analytical and Numerical Models of Thermoplastics: A Review Aimed to Pellet Extrusion-Based Additive Manufacturing

“…Similarly, in [ 55 ], an analytical model for the flow of Newtonian fluids in finite aspect ratio channels was proposed, and both the pressure-flow rate relation and flow field along the channel height for corn syrup, which can be assumed as a Newtonian fluid, were well predicted. In [ 36 , 56 , 57 , 58 , 59 ], the authors refer to correction factors for pressure and drag flow, as suggested in the case of Newtonian fluids in [ 43 ]; this is a really simple solution for taking into account the limited aspect ratio, and so the influence of both trailing and pushing flights on the flow field. Moreover, it has been shown that at least for the drag flow correction factor, there are no significant differences between the values measured for various polymers and the theoretical values calculated for Newtonian fluids [ 60 , 61 ].…”