The Study On The3-Dimensional Numerical Simulation Of Single Screw Extuder

The computational methods for3-dimensional mathematical models of the single screw extruder are investigated in this thesis. The single screw extruder is one of the most important equipment for polymer processing, and the research of numerical simulation for its fluid flow is a hotspot. There are few efficient numerical methods for the3-dimensional mathematical models due to the nonlinearity of the models and the time-varying characteristics and complexity of the domain of solution. In this thesis, we propose a new numerical method for the3-dimensional models of the single screw extruder based on geometry transformation and projection operator. The numerical results show that it is an efficient method for the models.The specific content of this thesis is as follows:1. The characteristics of single screw extrusion process, its mathematical models and the development of numerical methods for the models are briefly introduced.2. The method frequently-used in engineering, by which the screw channel is directly straightened into a Cylindrical domain, ignores the influence of screw and barrel surface and will lead to an error unable to eliminate. We derive a simple coordinate transformation which We derive a simple coordinate transformation which accurately transforms the time-varying and complex domain of solution into a Cylindrical domain. It can simplify the computation of the problem and is convenient for numerical simulation for the3-dimensional models.3. For the incompressible fluid, a new algorithm is developed for3-dimensional models of fluid flow in the single screw extruder, using the efficient projection algorithm and the above geometry transformation and a numerical example is given. The example shows that it is an efficient computational method.