船用双燃料发动机引燃燃料在可燃混合气氛围内着火及火焰传播机理研究

从多元化能源利用、环境保护以及经济性、安全性等角度考虑，天然气作为船舶内燃机燃料具有光明的前景。在天然气可用的几种燃烧方式中，因柴油微喷引燃的燃烧方式可以获得令人满意的性能而备受关注。这种高十六烷值燃料引燃可燃预混合气过程相对复杂，目前可查阅文献对其工程层面的研究居多，基础实验研究匮乏，数值模拟研究也不够深入。本项目拟通过综合的光学测试方法，结合化学动力学、一维小火焰模拟及三维CFD数值模拟，对微喷引燃燃料混合气形成、火核形成及其燃烧低温与高温反应历程，引燃燃料喷射引起的湍流与预混合气燃烧火焰的耦合作用过程、预混合气着火后的火焰传播和主要排放物生成过程、有氢气参与的引燃燃烧过程开展研究，以获取可燃预混气氛围下微喷引燃燃料混合气形成及燃烧特性参数影响规律，揭示引燃燃料喷射引起的湍流特征及其与燃烧火焰的相互作用机制，阐明预混合气火焰传播规律及排放特性，探寻拓展预混合气稀浓界限的方法。

From the perspective of the diversification of energy utilization, environmental protection, economy and safety, natural gas has a bright future as an alternative fuel to marine engines. Among the several combustion modes available for natural gas, diesel micro-pilot ignition has drawn much attention for its satisfactory combustion performance. The process of the combustible premixture ignited by a high-cetane-number fuel is relatively complex, and the available literatures mostly focused on the engineering development, lack of fundamental experiments, and numerical simulation is also not deep enough. In this project, comprehensive optical diagnostics, combining with chemical kinetics, 1D flamelet and 3D CFD numerical simulation, is used to investigate its processes: the formation of the mixture of pilot fuel in combustible mixture environment, the formation of the flame kernel and low temperature and high temperature reaction processes, the coupling of turbulence caused by pilot fuel injection with premixed combustion flame, the propagation of flame after the premixture is ignited, and the formation of major emissions, ignition and combustion processes when adding hydrogen, to obtain the formation and combustion characteristics of the pilot fuel mixture under the premixed combustible ambient, reveal the characteristics of turbulence induced by pilot fuel injection and its interaction with combustion flame, clarify the flame propagation and emission characteristics of premixed gas, and explore methods to extend the combustion limit of premixed gas.