Numerical Modeling of Spark Ignition in Aerial Internal Combustion Engines Using Low Cetane Number Synthetic Aviation Fuels

Ignition assistance (e.g., glow plugs) strategies have been used in compression ignition (CI) engines to enhance combustion of low cetane number jet fuel blends from cetane number (CN) 25 to 35. However, when using synthetic aviation fuels (SAF) such as alcohol-to-jet (ATJ), the CN can go as low as 17. Therefore, additional ignition assistant strategies such as spark igniters are investigated in this study. Computational Fluid Dynamics (CFD) simulations are employed to analyze the ignition characteristics of low cetane number (CN 17) ATJ SAF in a spark assisted compression ignition optical engine. The influence of various parameters such as the spark igniter penetration depth, spark igniter rotation angle, and fuel spray injection angle are analyzed. Two energy source models (cylinder and line) are investigated for the spark ignition model. The results show that the spark igniter is capable of enhancing ignition even for very low CN SAF at optimal configurations.