聚甲氧基二甲醚/柴油混合燃料柴油机缸内燃烧过程的数值模拟研究

Numerical Simulation Investigation on the Combustion Processes of a Diesel Engine Fueled with PODE/Diesel Blends

为研究聚甲氧基二甲醚/柴油混合燃料柴油机的缸内燃烧过程和污染物生成过程,建立了WP12.460型国VI柴油机的数值计算模型,采用三维CFD软件FIRE进行了数值模拟计算。结果表明,模拟得到的缸内压力曲线与试验值吻合良好;PODE的高十六烷值特性使得燃烧始点提前;随着PODE掺混比的增大,缸内压力峰值、缸内平均温度峰值和瞬时放热率峰值均逐渐降低,累积放热量逐渐减少;掺混PODE后,柴油机的NO排放增多;掺混PODE提高了可燃混合气的均匀性,同时PODE的高含氧量特性提高了缸内氧浓度,有效抑制了碳烟的生成。

In order to investigate the in-cylinder combustion process and pollutants formation process of Polyoxymethylene dimethyl ethers (PODEn)/diesel blends, a numerical model of WP12.460 China VI emission standards diesel engine was established and the three-dimensional numerical simulation was studied by FIRE software. The results showed that the calculation in-cylinder pressure curves were in good agreement with the experimental values. The start of combustion was advanced due to the high cetane number of PODE. With an increase in PODE blending ratio, the peak values of in-cylinder pressure, mean charge temperature and heat release rate decreased, and the accumulated heat release decreased. The addition of PODE led to a higher NO emission. The formation of soot emission was inhibited with the addition of PODE because the in-cylinder oil-gas mixture was improved and the oxygen concentration was increased.