Investigation of spray dynamics and combustion on different combustion chambers and spray models in internal combustion engines

In recent years, both engine performance and increased pollution awareness and the consequent introduction of stringent emission norms throughout world are forcing researchers to continue to investigate for strategies for reducing emissions. During fuel injection in diesel engines, the air motion plays a very important role in fuel-air mixing, spray dynamics and emission formation, especially around the compression TDC. Along with air motion, engine speed, combustion chamber shape, spray characteristics and alternative fuels also have a significant effect on diesel engine combustion. Several researchers have studied the in-cylinder processes, experimentally and computationally, to understand combustion in diesel engines. In the current study, it was of investigate to determine the emission reduction capability and engine performance of the combined effect of advanced injection strategies, engine speed, different combustion chamber geometry and alternative fuels in a multiple fuel injection diesel engine through Computational Fluid Dynamics (CFD) simulation and experimental methods. The numerical study was created using AVL-FIRE ESE Diesel Tool. Exhaust and intake ports are not included in the computational study by concentrating this study on in-cylinder flow and combustion processes. Numerical study has been used WAWE model for spray break-up, K-F model for solved of turbulence characteristics and ECFM-3Z (Extended Coherent Flame Model-3 Zone) combustion model for combustion. The experiments were performed on a four cylinder and four stroke multiple fuel injection diesel engine. The cylinder pressure was measured at a pressure transducer which was mounted on the cylinder head. And the same time was measured crank angle through a crank shaft encoder. This experiment aims at the internal characteristics of this engine, during which the combustion pressure, temperature, heat release rate, spray propagation, flame development, pollutant emissions and engine torque are studied.