Abstract Over the last decades, researchers devote to improving the combustion and emission performance of conventional fuels. Nanofuels, which are suspensions of energetic nanomaterials in liquid media, was proposed and became a promising alternative fuel. Optimizing the blend of nanoparticles and hydrocarbon fuels can dramatically decrease the world’s demand for fossil fuels without modifying state-of-the-art engines, and it can also significantly reduce pollutant emissions. However, our knowledge about nanofuels remains limited. Here, we experimentally investigated the spray and combustion characteristics of boron/ethanol nanofuels. We explore the effects of the size and the doping concentration of boron particles on suspension quality and the corresponding spray and combustion behavior. The nanofuels were prepared using boron particles, 100 nm and 400 nm in diameter, at particle loading concentration of 0.5 wt% and 1.0 wt%, respectively. The spray flame was operated on a modified McKenna burner using a coaxial air-assisted atomization method. The burner features a retractable fuel capillary injector, and the influence of capillary recess length on spray flames was studied in this work. Mie scattering was applied to investigate the spray characteristics of the ethanol and boron/ethanol nanofuels in non-reacting and reacting flows. Chemiluminescence was adopted to study the heat release of the target flames and the ignition delay of the boron particles during combustion. High-speed measurements offer us an opportunity to investigate the instantaneous phenomena during spray and combustion, and thus Mie scattering and chemiluminescence were operated at 50 kHz in our study.

中文翻译：

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利用50 kHz重复频率高速激光测量硼/乙醇纳米燃料的喷雾和燃烧特性研究

摘要 在过去的几十年里，研究人员致力于提高传统燃料的燃烧和排放性能。纳米燃料是高能纳米材料在液体介质中的悬浮液，被提出并成为一种有前途的替代燃料。优化纳米粒子和碳氢化合物燃料的混合可以在不改造最先进的发动机的情况下显着降低世界对化石燃料的需求，它还可以显着减少污染物排放。然而，我们对纳米燃料的了解仍然有限。在这里，我们通过实验研究了硼/乙醇纳米燃料的喷雾和燃烧特性。我们探讨了硼颗粒的大小和掺杂浓度对悬浮液质量以及相应的喷雾和燃烧行为的影响。纳米燃料是用硼颗粒制备的，直径分别为 100 nm 和 400 nm，颗粒负载浓度分别为 0.5 wt% 和 1.0 wt%。使用同轴空气辅助雾化方法在改进的 McKenna 燃烧器上操作喷雾火焰。燃烧器具有可伸缩的燃料毛细管喷射器，在这项工作中研究了毛细管凹槽长度对喷雾火焰的影响。应用米氏散射来研究乙醇和硼/乙醇纳米燃料在非反应流和反应流中的喷雾特性。采用化学发光法研究了目标火焰的放热和硼颗粒在燃烧过程中的点火延迟。高速测量为我们提供了研究喷雾和燃烧过程中瞬时现象的机会，因此在我们的研究中，米氏散射和化学发光在 50 kHz 下运行。