Numerical Simulation And Experimental Study On Flow And Heat Transfer Of Material In Triple-Screw Extruder

Screw extruder is important in the field of polymer molding equipment, and the ability to blend is very important for material blending modification. Triple-screw extruder of triangle arrangement is a new type of screw extruder equipment, and its three meshing region and characteristic central area can facilitate material mixing. Nowadays, study for the flow and heat transfer mechanism of the triple-screw extruder is little; there is no perfect evaluation system to evaluate the pros and cons of triple-screw extruder. Therefore, in this article the existing three screw industrial machine and homemade screw simulator are used for blending experiment and flow experiment. At the same time, the finite element analysis software POLYFLOW is used to build the transient and steady state model of triple-screw extruder, and results by numerical calculation method are compared with the experimental results. On the basis of the numerical calculation method is proven to be reliable, the further study of flow and heat transfer is carried out, which established a comprehensive evaluation way about flow and heat transfer, and provided certain theoretical basis for industrial production. The main research content is as follows:1. By the experiments of the triple-screw industrial machine and simulator, flow mixing performance of the triple-screw structure in different feed rate, screw speed and processing temperature is explored and the effect rule of variation about mixing and mechanical properties of preparation of products with process parameters is obtained from the experimental results, which can provide the process conditions to control the quality of the products.2. With the industrial machine and simulator experiment, transient model and the steady state model are established to compare the results of simulations and experiments and judge the reliability of the numerical model and the results used this paper. On the basis of comparing the dispersion and distribution mix performance of the triple-screw and twin screw steady-state model, the stretch shear ratio is linear increase with the increase of feed rate and is lower with the increase of the screw rotation speed. Stretch shear ratio of the triple-screw is higher than that of twin screw. Backflow coefficient is decreased with the increasing of feed rate, and increased with increasing of the screw rotation speed. Backflow coefficient of the triple-screw is 2-3 times than that of twin screw. Energy consumption of the triple-screw is higher than that of twin screw.3. The non-isothermal transient model of triple-screw structure under different processing temperatures and different screw element combination is used to find the effect of heat transfer and mixing performance. Through the analysis, it shows that the processing temperature increased promotes the effects of flow field, but the stretch effect is reduced relative to the shear effect, and it will consume more energy at the same time; The flow field of different screw element combination have different features for the flow and heat transfer effect of the material, which can provide fundamental basis for industrial manufacture.