Parametric analysis of the deaerator flow field using CFD

The present work is the result of a research project carried out by the Politecnico di Torino with GE Avio S.r.l. The aim of this work is the study of the parameters of air oil static separators, also known as de-aerators, which are fundamental devices of the lube system for aero engines. The role of these components is to separate the air oil mixture coming from the scavenge line and to deliver the purified oil to the tank. The separation is accomplished without any moving part. The flow is provided with a swirling motion and the resulting centrifugal effects manages to separate the two phases thanks to their different density. This process is strongly affected by the geometric dimensions and the boundary conditions. This study aims to understand the impact of the geometry on the de-aerator performances by using the computational fluid dynamics (CFD). The boundary conditions are fixed and so does the delta pressure. In the Chapter 1, there is a brief description of the lube system and its role in the jet engines. The Chapter 2, instead, provides a summary of the researchers regarding the static separators and the state of the art. Different models of analysis are briefly mentioned and compared. The Chapter 3 defines the geometry under study and describes the first step of the parameterization on a cylindrical geometry. The volume of fluid and the computational setup are detailed in the Chapter 4. Chapter 5 shows the results of the first step of the parametric study both in terms of flow field and collection efficiency. Two further analysis have been accomplished in the last two chapters. Chapter 6 reports an insight on the parameters’ interaction in a multiparametric analysis. Chapter 7 describes the effects of the outlet in the conical-cylindrical configurations. The summary of the present work allows to define a design strategy for a theoretical geometry.