船用LNG发动机掺烧模拟废气-燃料重整气缸内燃烧过程仿真

为研究废气燃料重整再循环技术(REGR)对船用LNG发动机性能的影响,搭建试验台架,进行性能测试;运用AVL-fire软件建立发动机燃烧室仿真模型,并依据试验数据验证仿真模型的准确性。基于该模型进行各负荷下不同废气再循环系统(EGR)率及在确定的EGR率下掺烧不同比例模拟重整气的仿真计算,并以75%负荷下的工况为例进行详细分析。计算结果表明,随着EGR率的升高,缸内平均压力和平均温度的峰值下降,燃烧过程整体后移,燃烧持续期增加,发动机的指示功率和NO比排放下降,指示燃油消耗率增加;掺混重整气比例增加,缸内平均压力和温度峰值升高,燃烧持续期缩短,指示功率和NO比排放升高,在重整气掺混率升高到一定程度时,指示燃油消耗率明显下降。综合分析发现,使用REGR技术可在不牺牲发动机的动力性和经济性的前提下降低液化天然气(LNG)发动机的NO比排放。

Simulation of In-cylinder Combustion Process of Marine LNG Engine mixed Simulated exhaust gas-fuel reforming gas

In order to study the effect of Reformed Exhaust Gas Recirculation (REGR) technology on the performance of marine LNG engines, the test bench was built and the performance was tested. The engine combustion chamber simulation was established using AVL-fire software, and the simulation model was verified according to the test data. Based on this model, simulation calculations under different loads were carried out for different EGR rates and for the simulation of mixed gas at different ratios under certain EGR rates, moreover, the working condition under 75% load was analyzed in detail. The calculation results show that with the increase of EGR rate, the average pressure in the cylinder and the peak value of the average temperature decrease, the combustion process moves backwards, the combustion duration increases, the engine''s indicated power and NO emissions decrease, and the indicated fuel consumption rate increases. The proportion of blended reformed gas increases, the average pressure and temperature peak in the cylinder increases, the combustion duration shortens, the indicated power increases, and the specific NO emission increases. When the reforming gas blending rate rises to a certain extent, the fuel consumption efficiency has dropped significantly. A comprehensive analysis shows that using REGR technology can reduce the NO emissions of LNG engines without sacrificing the engine''s power and economy.