Numerical simulation of turbulent flow inside the cylinder of a new two-stroke grail engine design

Abstract

This work presents a novel way of implementing Autodesk computational fluid dynamics (CFD) software for internal combustion (IC) engine application. The main objective of this research is to develop a high fidelity simulation methodology for a state of art hybrid two-stroke Grail engine and to investigate the complex motion of piston and intake valve of the engine. Grail engine design is unique due to presence of single intake valve within the piston itself. Thus, the intake valve moves with the piston which makes the motion much more complex to study in the present work. Since the efficiency of combustion and the production of pollutants in the internal combustion engine are strongly dependent on the turbulent flow field in the engine cylinder. The focus is put in the analysis of the in-cylinder flow field dynamics and turbulence within the cylinder and through the complete engine cycle in the initial stages of development of the Grail engine. Finally, the scavenging process of the Grail engine with mixing and scavenging efficiency was also numerically investigated. In most engines, turbulent kinetic energy (TKE) is almost exclusively generated during the intake stroke and enhances greatly the mixing of air and fuel to give better mixing during compression stoke. The 3-D simulation of the flow through the engine is performed by using finite element method. Autodesk Reynold's-averaged Navier-Stokes (RANS) K ?? model is used to perform the calculations of the flow. The performance and possibilities that Autodesk CFD gives for this kind of application is evaluated.