Abstract In this work, a comprehensive experimental investigation on spray characteristics of four blended fuels, including diesel (D100), diesel-biodiesel (DB), diesel-biodiesel- ethanol (DBE), and diesel-biodiesel-diethyl ether (DBDE) has been conducted by using high pressure common rail injection system (up to 200 MPa). The transient spray behavior under various conditions was recorded by high speed photography with scattering light illumination. It is shown that higher injection pressure significantly accelerates the spray tip penetration (STP) evolution due to increased inertia of spray while increase in ambient pressure reduces the STP evolution due to higher gas resistance. With the addition of diethyl ether (DEE) into biodiesel, the STP of blended fuel tends to go down and corresponding projected area increases a lot when compared to DB. By means of particle droplet image analysis (PDIA) optical diagnostic method, spray microscopic parameters such as Sauter Mean Diameter (SMD), droplet diameter distribution probability curve, cumulative volume curve and characteristic diameter have been investigated. Results show that both the injection pressure and ambient pressure have significant influence on the spray microscopic characteristics. In addition, for fixed injection pressure and ambient pressure, when DEE is added into DB blends, the number fraction of smaller droplets increases, though the statistic diameter with peak probability is fixed at a certain value. Furthermore, SMD of the four tested fuels decreases sequentially in the order of DB, D100, DBE, and DBDE, indicating that DEE addition favors the atomization process.

中文翻译：

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乙醇和乙醚添加对高喷射压力下柴油/生物柴油共混物喷雾特性影响的实验研究

摘要 在这项工作中，对柴油 (D100)、柴油-生物柴油 (DB)、柴油-生物柴油-乙醇 (DBE) 和柴油-生物柴油-乙醚 (DBDE) 四种混合燃料的喷雾特性进行了综合实验研究。采用高压共轨喷射系统（高达 200 MPa）进行。在各种条件下的瞬态喷雾行为是通过高速摄影和散射光照明记录的。结果表明，由于喷雾惯性的增加，较高的喷射压力显着加速了喷雾尖端穿透 (STP) 的演变，而环境压力的增加由于较高的气体阻力而减少了 STP 的演变。在生物柴油中加入乙醚（DEE）后，混合燃料的 STP 趋于下降，相应的投影面积比 DB 增加很多。借助粒子液滴图像分析(PDIA)光学诊断方法，研究了Sauter平均直径(SMD)、液滴直径分布概率曲线、累积体积曲线和特征直径等喷雾微观参数。结果表明，注射压力和环境压力都对喷雾微观特性有显着影响。此外，对于固定的注射压力和环境压力，当 DEE 加入 DB 混合物时，较小液滴的数量分数增加，尽管具有峰值概率的统计直径固定在某个值。此外，四种测试燃料的 SMD 按 DB、D100、DBE 和 DBDE 的顺序依次降低，表明添加 DEE 有利于雾化过程。