Abstract
A CFD approach for single-cylinder intake port flow analysis using ANSYS Fluent 17.1 on a basic workstation was validated with flow bench measurements of volume flow rate. A digital model was created from 3D scans of a 2005 Ford 3.0L DOHC 4V Duratec V6 cylinder head with ¾” radius inlet flow guide. Pressure drop of 28” of water at valve lifts of 0.100”, 0.200”, 0.300”, 0.400”, and 0.500” was used for flow bench testing and for CFD. MeshLab and Meshmixer were used to prepare the surface meshes and Fluent automatic mesh generation was used to create tetrahedral volume meshes with approximately 325,000 cells. Transient solutions using standard k-ε and realizable k-ε turbulence modeling were compared to flow bench results. Realizable k-ε models achieved less than 8% error for all lift values except 0.100” and captured realistic flow behavior. Flow time required to reach steady state was different for each solution method and geometry; the best method was to use realizable k-ε with initial time steps of 1e-4s or 1e5s and loose convergence criteria until steady state is achieved, then reduce time step to 1e-6s for convergence. 0.100” lift models were the least accurate due to imprecise modeling of the valve seat region. At higher lifts, flow separation was suspected but no reversed flow was found. A finer mesh may be necessary to capture this behavior. Improvements to the approach are discussed to allow study of port shape changes and higher levels of CFD analysis for the Duratec V6.