A numerical analysis of the air flow through the IC engine intake manifold

Engine intake systems should be carefully designed to provide a uniform flow to all cylinders. The current note presents the initial phase of the redesign process of an intake manifold of a four cylinder aircraft IC engine. By means of computational fluid dynamics analysis, the deficiency of the initial design in splitting the air flow among the runners is discovered, and an improvement of the original design is proposed. It is shown that a significant improvement in the flow distribution can be achieved by an appropriately installed guide vane, whereas the flow split is observed to be very sensitive to the geometry of the guide vane, necessitating a very careful design.