【作者】 刘青妍；

【导师】 乔信起；

【作者基本信息】 上海交通大学 ， 动力机械及工程， 2007， 硕士

【摘要】 随着人们对能源短缺和环境保护的日益关注,降低发动机能源消耗和排放成为发动机开发的两个主要问题。目前研究比较多的两种途径是对传统内燃机进行改进和研制替代能源内燃机。甲醇来源广泛,甲醇重整气(RMG,Reformed Methanol Gas)是一种优良的氢气载体。目前甲醇重整气用于内燃机的研究刚刚起步。本文基于燃料氧化的化学动力学理论,采用数值模拟方法研究了甲醇重整气的预混合燃烧和性能。另外,对传统柴油机进行氧化剂改进也是改善排放的途径之一。本文运用三维数值模拟程序研究了进气成分对柴油机燃烧的影响,并进行了台架试验。运用详细化学动力学机理和CHEMKIN计算程序,对甲醇重整气在改装柴油机上的预混合燃烧进行数值模拟。研究表明,采用单区燃烧模型可准确预测着火时刻和NOx排放,甲醇重整气预混合燃烧具有单阶段放热特性,NOx排放极低。通过对中间产物的浓度变化进行分析,了解了甲醇重整气燃烧的化学反应历程,找出了重要自由基和关键中间产物。尝试使用增压来解决功率过低以及进气需加热的问题,结果表明,增压不中冷是比较可行的。还对重整气成分变化对燃烧和排放的影响作了分析。运用三维数值模拟程序KIVA-ⅢV模拟了进气成分对柴油机扩散燃烧的的影响。采用RNG k-ε湍流模型和详细化学反应动力学机理,考察了2135柴油机在进气中添加不同比例CO2、推迟供油时的燃烧和排放。在2135柴油机上进行了氧化剂改进的试验研究。改变进气中氧气的含量,研究其对柴油机燃烧和排放的影响;调整(推迟)供油,考察不同供油时刻下柴油机的燃烧和排放,以了解这一措施对富氧带来的负面效应是否有抑制;在富氧进气中掺入不同比例CO2,以研究CO2和富氧共同作用下柴油机的性能。更多还原

【Abstract】 Reducing fuel consumption and engine emissions is the major objective in engine development in light of increasing concern about energy shortage and environmental protection. The main two solutions are improvement on conventional diesel engines and gasoline engines, and development of alternative fuel engines. Methanol has a rich source of raw materials and Reformed Methanol Gas (RMG) is an excellent hydrogen carrier. Now there hasn’t been too much research on RMG fueled internal combustion engines. Therefore, the pre-mixed combustion and NOx emissions of RMG were investigated using numerical simulation based on chemical kinetics in this paper. Oxidizer improvement is another way to decrease emissions. Three-dimensional CFD program was used to simulate the effects of inlet gas composition on the combustion in diesel engines. And the corresponding experiments were carried out.Detailed chemical kinetics mechanism and CHEMKIN software were used to simulate the premixed combustion of a refitted Volvo TD100 engine fueled with RMG. The results show that the ignition timing and NOx emissions predicted by using single-zone combustion model have a good agreement with measured results, and RMG HCCI combustion is characterized by single-stage heat release. NOx emissions are very low. The key species (OH、H、O、HO2 and H2O2) histories were analyzed to determine important reactions and the overall reaction scheme for RMG. Supercharging was introduced to solve the problems of low output horsepower and inlet gas heating. It was found that appropriate supercharging without inter-cooling更多还原