Numerical Simulation of the Filling and Curing Stages in Reaction Injection Moulding

ISBN-13: 9783656649243 / Angielski / Miękka / 2014 / 126 str.

Rui Igreja

Opis

Master's Thesis from the year 2007 in the subject Engineering - Mechanical Engineering, language: English, abstract: (Thesis in pdf available here: http: //goo.gl/EZzlT6 and here: http: //hdl.handle.net/10773/2419) Commonly used methods for injection moulding simulation involve a considerable number of simplifications, leading to a significant reduction of the computational effort but, in some cases also to limitations. In this work, Reaction Injection Moulding (RIM) simulations are performed with a minimum of simplifications, by using the general purpose CFD software package Ansys CFX, designed for numerical simulation of fluid flow and heat and mass transfer. The Ansys CFX's homogeneous multiphase flow model, which is generally considered to be the appropriate choice for modelling free surface flows where the phases are completely stratified and the interface is well defined, is shown to be unable to model the filling process correctly. This problem is overcome through the implementation of the inhomogeneous model in combination with the free-slip boundary condition for the air phase. The cure reaction is implemented in the code as a transport equation for an additional scalar variable, with a source term. Various transient and advection schemes are tested to determine which ones produce the most accurate results. Finally, the mass conservation, momentum, cure and energy equations are implemented all together to simulate the simultaneous filling and curing processes present in the RIM process. The obtained numerical results show a good global accuracy when compared with other available numerical and experimental results, though considerably long computation times are required to perform the simulations.