For researching the influence of n-butanol proportion in diesel fuel on homogeneous charge compression ignition (HCCI) combustion of the free-piston diesel engine generator (FPDEG), a three-dimensional (3D) moving mesh computational fluid dynamics (CFD) simulation model of a FPDEG prototype was developed. A detailed chemical reaction mechanism of diesel fuel was selected as the HCCI combustion mechanism and coupled in the established HCCI combustion simulation model of the FPDEG prototype. The validity of the established HCCI combustion simulation model is proved by comparing the simulation and experimental pressure curves under the condition of pure diesel fuel. The simulation results of different n-butanol proportions in diesel fuel showed that as the n-butanol proportion increased from 0 to 60%, the maximum heat release rate decreased to 59.6 J/deg, the calculated indicated thermal efficiency augmented to 4.6%, the calculated indicated mean effective pressure increased to 0.057 MPa, and the final NO_x and CO content decreased to 0.239 and 0.57 g/kg fuel, respectively, but the final soot content increased to 0.000562 g/kg fuel. Therefore, the n-butanol proportion of diesel fuel played a vital role in combustion and emission progress of the FPDEG.

中文翻译：

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正丁醇配比对自由活塞柴油发电机HCCI燃烧影响的模拟研究

为研究柴油燃料中正丁醇比例对自由活塞柴油发电机 ( FPDEG ) 均质充气压燃 (HCCI) 燃烧的影响，采用三维 (3D) 移动网格计算流体动力学 (CFD) 仿真模型开发了 FPDEG 原型。选择柴油燃料的详细化学反应机理作为HCCI燃烧机理，并耦合到已建立的FPDEG原型HCCI燃烧模拟模型中。通过对比纯柴油条件下的模拟和实验压力曲线，证明了所建立的HCCI燃烧模拟模型的有效性。柴油中不同正丁醇比例的模拟结果表明，随着n-丁醇比例从0增加到60%，最大放热率降低到59.6 J/deg，计算的指示热效率提高到4.6%，计算的指示平均有效压力提高到0.057 MPa，最终NO _x和CO含量分别降至 0.239 和 0.57 g/kg 燃料，但最终碳烟含量增加到 0.000562 g/kg 燃料。因此，柴油燃料的正丁醇比例对FPDEG的燃烧和排放过程起着至关重要的作用。