CFD simulations on EGR mixing in the inlet manifold of a combustion engine
Examensarbete för masterexamen
In this work CFD is applied to simulate and estimate the EGR distribution in a combustion engine. CFD is a numerical method for simulating flows in a wide range of applications. EGR is a method that involves recirculation of exhaust gases into the inlet manifold of an engine. The aim of this thesis is to evaluate different simulation methods for estimating the EGR distribution into the different cylinders of a six cylinder Scania engine. Initially, simulations were conducted on a simple T-junction in order to analyze how different parameters affect the mixing process. Data from a reference case involving a mixing experiment was used in order to verify the CFD simulations on the T-junction. The optimal settings from the T-junction simulations were applied on the inlet manifold of the Scania six cylinder engine. Furthermore, the engine simulations were carried out with three different approaches. These three approaches are distinguished in the way their boundary conditions are applied. The first approach has simplified boundary conditions at the valves and does not account for backflows. The second approach is set up by generating realistic boundary conditions from a 1-dimensional simulation. The third approach is a coupled simulation meaning that an active coupling exists between the 1-dimensional code and the 3-dimensional CFD code. Experimental measurements of the EGR distribution have been conducted within another master thesis. Data from the CFD simulations have been compared to the experimental data. Qualitative and quantitative conclusions were drawn regarding the EGR distribution. Access to experimental data from the engine test cell has contributed to the validation of these simulations.
Hållbar utveckling , Transport , Strömningsmekanik , Sustainable Development , Transport , Fluid mechanics