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In this work simulation results of a round spray jet are presented using the combination of Large-Eddy Simulation (LES) and Lagrangian Particle Tracking (LPT). The simulation setup serves as a synthetic model of non-atomizing spray particles taken from the Rosin-Rammler size distribution that enter a chamber filled with gas through an inlet hole with diameter D. At the inlet gas velocity and droplet velocities are specified in addition to the initial size distribution of droplets. The Reynolds number as referred to the gas inflow velocity and jet diameter is Re=10000. The setup is advantageous for understanding the details of diesel sprays since it avoids near-nozzle spray modeling and thereof the corresponding error which is especially important in LES. Here, the implicit LES is applied so that the compressible Navier-Stokes equations are solved directly with a numerical algorithm in a fine mesh without a subgrid scale model.

To improve today’s 1D engine simulation techniques it is important to investigate how well complex geometries such as the manifold are modeled by these engine simulation tools and to identify the inaccuracies that can be attributed to the 1D assumption. Time resolved 1D and 3D calculations have been performed on the turbulent flow through the outer runners of an exhaust manifold of a 2 liter turbocharged SI engine passenger car The total pressure drop over the exhaust manifold, computed with the 1D and 3D approach, showed to differ over an exhaust pulse. This is so even though a pressure loss coefficient correction has been employed in the 1D model to account for 3D flow effects. The 3D flow in the two outer runners of the manifold shows the presence of secondary flow motion downstream of the first major curvature. The axial velocity profile downstream of the first turn loses its symmetry. As the flow enters the second curvature a swirling motion is formed.

Turbochargers are commonly used in automotive engines to increase the internal combustion engine performance during off design operation conditions. When used, a most wide operation range for the turbocharger is desired, which is limited on the compressor side by the choke condition and the surge phenomenon. The ported shroud technology is used to extend the operable working range of the compressor, which permits flow disturbances that block the blade passage to escape and stream back through the shroud cavity to the compressor inlet. The impact of this technology on a speed-line at near optimal operation condition and near surge operation condition is investigated. A numerical study investigating the flow-field in a centrifugal compressor of an automotive turbocharger has been performed using Large Eddy Simulation. The wheel rotation is handled by the numerically expensive sliding mesh technique. In this analysis, the full compressor geometry (360 deg) is considered.