A Methodology to Estimate the Swirl Number at TDC In DI Diesel Engines: Through the Combination of CFD and Steady Flow Rig Results

The aim of this paper is to analyse the swirling flow in the cylinder of DI Diesel engines. Both steady state flow rig and CFD calculation techniques on three Diesel engines at different configurations have been used to carry out this study.

On one hand, results obtained by means of steady state flow rig measurements with torque-meter are presented. On the other hand, the intake and compression strokes are calculated using a CFD commercial code on real geometries of three engines at different working conditions. The experimental and the CFD methods are compared in terms of Swirl Number and Flow Coefficient, so some correlations are achieved at BDC and TDC and a general equation -valid for different geometries- has been obtained to estimate the Swirl Number in the cylinder of DI Diesel engines at TDC directly from the data -Mean Swirl Number- provided by the experimental tests.