Computational Studies Of Gas Injection Ignition And Combustion Emissions In A Direct Injection Natural Gas Engine

Download or read book Computational Studies of Gas Injection, Ignition and Combustion Emissions in a Direct-injection Natural Gas Engine written by Kang Pan and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The direct-injection of natural gas into the compression-ignition engines is attractive, due to its emission advantage and diesel-equivalent efficiency. The computational simulation of this next-generation heavy-duty engine can provide deep insights of the gas injection and ignition characteristics and help understand the emission formation process, and hence, a KIVA-3v based three-dimensional computational model was developed and improved to represent the configuration of a glow plug assisted direct-injection natural gas engine. This thesis presents the important conclusions about the numerical studies of the natural gas ignition and emissions by using this engine computational model. Preliminary simulations revealed that the shield for a glow plug, an ignition assist for natural gas in compression-ignition engines, can highly improve the natural gas ignition stability compared to an unshielded glow plug, and the design of the glow plug shield has great potential for the further improvement of the natural gas ignition. The different shield designs, characterized by the parameters such as shield opening shape, number and distribution, were evaluated by using the improved KIVA model. The simulated results clearly demonstrated the three key functions of a good shield design. A multi-opening shield, consisting of four small openings in a diamond shape, can achieve all three requirements and hence highly reduce the natural gas ignition delay and improve the ignition stability, compared to the original single-opening shield. The proper emission models are critical for the numerical simulations of natural gas engine emissions. For the gaseous species, a kinetic package, CANTERA, is coupled to KIVA CFD code to simulate the formation of important emissions, such as C2H2 and NOx. However, the available detailed mechanisms, such as GRI-3.0, will over-predict the ignition delay at low temperature (