初期乱流場を考慮したHCCIエンジン燃焼過程の数値解析

概要

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In recent years, the homogeneous charge compression ignition engine is attracting a great interest because it is capable of reducing both nitrogen oxide and particulate matter emissions significantly. However, some problems remain unresolved, such as the limited range of running condition and the difficulty of controlling ignition timing. In order to solve these problems, it is necessary to comprehend the mechanism of compression auto ignition combustioa In this study, the auto ignition and combustion process of isooctane and air homogeneous mixture in an HCCI engine has been simulated by a multi- dimensional CFD computation. The chemical reaction is described by using a 5-step global reaction model for hydrocarbon fuels. The Very Large Eddy Simulation (VLES) was employed to describe turbulent transport. The initial velocity fluctuation has been provided by a method reforming velocity-correlation to give a statistically reasonable fluctuating turbulent flow field at the intake valve closing time. The results show that some auto ignition locations appear near the wall at first, then randomly in the combustion chamber. And, the flames propagate rapidly from these auto ignition locations.
香川高等専門学校の論文