Modelling of compressible fluids behaviour for LCM applications

The main objective of this work is to take into account compressible fluids behaviour in those numerical models designed to represent the liquid resin flow through fibrous architectures. The aim of these models is to simulate and optimize composite materials manufacturing processes and, more specifically, the Liquid Composite Molding (LCM) method which is increasingly being adopted for the elaboration of next generation high performance composites for aerospace applications. Indeed, one of the issues related to these processes is the possible presence of voids in the finished composite part caused by air entrapment or out-gassing phenomena during the elaboration step. Thus, in order to ensure the quality of manufactured parts, it is important to understand and simulate phenomena caused by the presence of gas and so to consider its compressibility. In the first part of the document, after having introduced the context and the objectives, the state of art of resin flow modelling through fibrous structures is presented. The second part is dedicated to the derivation of the adopted mathematical model and the presentation of numerical methods which have been considered to solve it and to extend its applicability to a bi-phase configuration in which the simultaneous presence of resin and air is represented. The last part of the work presents some test cases which have been developed to validate the implementation of the adopted numerical model in the Z-Set code.