Application of Lda And Piv Techniques to the Validation of a Cfd Model of a Direct Injection Gasoline Engine

Two experimental techniques, Particle Image Velocimetry (PIV) using a water-analogy Dynamic Flow Visualisation Rig (DFVR) and Laser Doppler Anemometry (LDA) in a motored research engine, were used to investigate the flow pattern generated within the combustion chamber of a gasoline direct injection (G-DI) engine. The in-cylinder flow was also modelled for the two cases using the Computational Fluid Dynamics (CFD) code VECTIS; that is, models were created using first water and then air as the working fluid. The experimental and computational results were converted into the same format and hence compared qualitatively and quantitatively. All results showed good agreement and were used to validate the different techniques. The correlation between the CFD air simulation results and the LDA results demonstrates that the CFD code can be used to predict reliably the air motion created in the combustion chamber of a G-DI engine. The results from the CFD simulations using air and water showed the same general flow pattern within the induction stroke. The fact that the results from the DFVR also compared favourably with the CFD water and air models, indicates that these techniques can be used confidently in the development of the ports and combustion chamber of a G-DI engine.