燃料物性和喷油策略对船用柴油机性能和排放影响的模拟研究

Numerical Study on Effects of Fuel Properties and Injection Strategies on Performance and Emissions of a Marine Diesel Engine

采用多维数值模拟的方法系统研究了不同燃油性质和喷油策略对船用柴油机性能和排放的影响。研究结果表明:无论使用重油还是轻油,采用顺序喷射、预喷和后喷都能在降低燃油消耗率的同时降低NO_x排放;顺序喷射方案能在两个喷油器的喷射间隔为4°时达到最低的燃油消耗率;大比例预喷匹配合适的主预喷间隔容易获得较低的燃油消耗率,小比例预喷匹配合适的主预喷间隔容易获得较低的NO_x排放;后喷策略对燃油消耗率改善不明显,随着主后喷间隔增大或者后喷油量的增加,燃油消耗率均呈现增加的趋势。

The effects of fuel properties and different injection strategies on the performance andemissions of a marine diesel engine were investigated by using computational fluid dynamics （CFD）simulations. The results show that no matter what kind of fuel is used, heavy or light diesel fuel, thesequential injection, pilot-injection and post-injection all have potential in reducing NO：, emission and fuelconsumption simultaneously. The lowest fuel consumption can be obtained using the sequential injectionstrategy with Seq4 （the injection interval between two injectors being 4〇）. Lower fuel consumption and lower NO.emission can be easily realized by using the pilot-injection of large proportion and small proportionrespectively with proper injection interval between the main-injection and pre-injection. Fuel consumption cannot be significantly reduced using the post-injection strategy, and fuel consumption rises with theincreases in the injection interval between the main-injection and post injection, and in post-injectionquantity.