Application of Lda and Piv Techniques to the Validation of Vectis Using Boundary Mesh Motion

Computational fluid dynamics (CFD) is being increasingly used to analyse gasoline direct injection (G-DI) combustion systems in the early stages of design and development. Consequently, it is important to ensure that the CFD codes are both fast and accurate. The objective of the work presented in this article was to validate the new, advanced boundary motion capability of VECTIS which is built on it's industry-proven automatic meshing capabilities. Two experimental techniques were used to investigate the flow pattern generated within the combustion chamber of G-DI engine. The first was Particle Image Velocimetry (PIV) using a water-analogy Dynamic Flow Visualisation Rig (DFVR). The second technique was Laser Doppler Anemometry (LDA) in a motored engine. Finally, the results were compared directly to CFD predictions. 2 INTRODUCTION The design of a direct injection gasoline combustion system, compatible with both early and late injection operation, creates a difficult challenge. There are many interacting variables, including fuel injection characteristics, fuel spray targeting, injection timing, ignition timing, combustion chamber geometry and charge motion, which are particularly hard to optimise. To design a G-DI combustion system efficiently, it is therefore necessary to understand the complex interactions and influences of all of the parameters.