Investigation of the flow field in the various regions of intake manifold of a SI engine

The main objective of the present work is to make a computational study of steady flow through intake manifold, port, valve and valve seat of a S. I. engine for various valve lifts. Three-dimensional flow within the manifold, port and valve has been simulated using the computational fluid dynamics (CFD) using the code STAR-CD. Flow field details in the identified regions in the manifold for the various valve lifts have been predicted. Analysis has been carried out for runners 1 and 3 at three different valve lifts for various speeds at wide-open throttle condition. A trimmed cell (adjust and cut process based on an underlying structured grid) has been adopted for meshing the geometries. Flow has been simulated by solving governing equations, viz., conservation of mass and momentum using the SIMPLE-algorithm. Turbulence has been modeled by high Reynolds number version of k-epsilon model. Mass flow rate measurements have been made for validating the numerical prediction. A reasonably good agreement has been obtained between predicted and the experimental results. Also, it is seen that valve lift has a predominant effect on flow structure and it is found that with increase in valve lift there is a tendency for flow separation near the valve seat region.