Validation of Turbulent Flow in a Two-Stroke Grail Engine Cylinder

Abstract

 The validation of results obtained from a static computational fluid dynamics (CFD) simulation of a state-of-the-art hybrid two-stroke Grail internal combustion engine design to analyze the effects of the intake hole and channel shape on in-cylinder flow turbulence is presented in this research. The turbulent flow dynamics within the cylinder have a significant impact on combustion efficiency and pollution production in an internal combustion engine. Turbulent kinetic energy (TKE) is almost entirely generated during the in-take stroke in most engines. This considerably improves the mixture of fuel and air during the compression stage, resulting in better mixing. Therefore, in the current investigation, a considerable effort was made to focus on analyzing the effects of the intake hole, the duct shapes of the Grail engine on the incylinder flow dynamics. The analysis of the Grail Engine design flow field using Autodesk CFD software has produced promising results. A violent tornado-like effect is seen in the flow field. The swirl effect of the flow was observed with a single vortex located at the cylinder's axis. The Grail Engine's resulting flow field will provide an ideal homogeneous/stoichiometric fuel-air combination for increased combustion efficiency. The result of 3-D static simulations of the flow through the engine had provided guidelines on selection of several geometrical parameters for optimal performance. The values of velocity profiles and the velocity vector contours obtained from the numerical simulation are well within the limits obtained from the references.