Development of a 1D to 3D CFD couplingmethodology on an inlet manifold

Abstract: We investigate the coupling between 3D simulations of the flow in an engine manifold with simplified 1D models of the engine performance. The inlet manifold in an existing 1D engine model is replaced with a more sophisticated CFD manifold simulation. The rest of the 1D system is left untouched. The CFD model can better capture mixing effects and the geometry of the manifold. The lorry developer Scania provides the 1D engine model together with the corresponding manifold geometry. Inexperienced readers are introduced to related work and underlying theory in the area. The CFD manifold simulation is developed and validated in terms of sensitivity to the grid, choice of turbulence model and surface roughness. Comparisons with the original system are made for a selection of relevant engine predictions along with manifold flow quantities. Minor effects in the predictions are observed at a hefty price in computational time and in implementation effort.