Experimental Studies of Flow Fields in Internal Combustion Engines

Abstract

An experimental study based on Laser Doppler Velocimetry (LDV) measurements was used to investigate the effects of piston geometries and intake swirl levels on the structure of flow quantities at the top dead center (TDC) position of a simulated internal combustion engine (ICE). Rapid intake and compression machine (RICM) was used for this study. The two combustion chamber types investigated were the bowl-in-piston and the re-entrant bowl geometries. The experimental results show that turbulence is produced around the TDC position in the high-shear regions formed near the piston bowl rim. These high-shear regions were established by the interaction of squish and swirl. The results also show that the intake-generated turbulence has significantly decreased such that its influence on turbulence at TDC was negligible. In general, it was observed that turbulence around TDC was more intense in the re-entrant bowl under all swirl conditions than in the bowl-in-piston combustion chamber. The results of the data from this study show that the random uncertainties in the mean radial and tangential velocities for both chamber configurations ranges from ±13.2% to ±19.2%, while the uncertainties in the root mean square velocities were about ±14.1%.