Numerical analysis of flow dynamics for two piston bowl designs at different spray angles

Abstract

The main objective of the present study is to find the need of technology transformation from hemispherical bowl piston geometry to re-entrant piston bowl geometry. The two different piston bowl geometries were examined by the application of different spray angles. The NO and Soot emission characteristics for both geometries were measured and performance parameters were also evaluated to justify the use of geometry as a part of combustion study. A commercial CFD simulation software AVL FIRE was used to evaluate re-entrant and hemispherical bowl piston geometry. Easily available hemispherical bowl piston geometry of Kirloskar single cylinder diesel engine was used for comparison and validation purpose. The effect of spray angles such as 120°, 140° and 160° tested on both geometry, while comparison has drawn for emissions and performance parameters. Results indicated that, NO and Soot mass fraction of 120° and 160° spray angle is lowest respectively. Whereas, NO emissions are reduced to 66% at 120° spray angle in case of a Re-entrant piston bowl than hemispherical bowl piston geometry. However, the soot mass fraction shows same response for both geometry at 160° spray angle.