Large Eddy Simulation of Direct Injection Processes for Hydrogen and LTC Engine Applications 2008-01-0939

Direct injection (DI) has proven to be a promising option in Diesel and low temperature combustion engines. In conventional Diesel and homogeneous charge compression ignition (HCCI) applications, DI lowers soot and NO_x production and improves fuel economy. In hydrogen fueled engines, DI provides the appropriate energy density required for high efficiency and low NO_x emissions. To realize the full benefit of DI, however, the effect of various injection parameters, such as injection timing, duration, pressure, and dilution, must be investigated and optimized under a range of engine operating conditions. In this work, we have developed a model for high-fidelity calculations of DI processes using the Large Eddy Simulation (LES) technique and an advanced property evaluation scheme. Calculations were performed using an idealized domain to establish a baseline level of validation. The theoretical-numerical framework combines a general treatment of the governing conservation and state equations with state-of-the-art numerical algorithms and massively-parallel programming paradigms. This software enables both the canonical cases described here and in-cylinder calculations. Here we focus on high-pressure multi-port gas injectors designed for application in hydrogen-fueled IC-engines. This study was conducted in support of a larger effort to perform detailed in-cylinder LES calculations of companion optical engine experiments.