To solve the negative environmental problems derived from the transport sector, this study is devoted to realizing a thorough substitution of biomass fuels for petroleum diesel. The spray, ignition, combustion, and emission of pure biodiesel, biodiesel/ethanol blend, and two kinds of biodiesel/ethanol/water triple micro-emulsified fuels were studied through optical visual methods on a constant volume combustion chamber. First of all, the micro-emulsified fuels obviously improve the spray quality. The micro-explosion effect of internal water improves the spray and atomization and the gas–liquid phase spray projected areas of microemulsion fuel at the maximum water blending ratio are the largest in the mid and late stages of spray. Secondly, with the increase of the water blending ratio, the combustion process of the fuel is improved. The flame lift-off length increases, the ignition delay period is prolonged, and the air entrainment effect is enhanced. Meanwhile, the combustion flame temperature decreases with the increase of water content, realizing low-temperature combustion. Lastly, the micro-emulsified fuels markedly decrease soot emissions. Both the total luminous intensities and normalized total KLs of micro-emulsified fuel with high water content are the lowest, achieving the best soot reduction effect. The triple micro-emulsified fuels have significant potential as a full biomass alternative fuel.

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生物柴油/乙醇/水微乳化燃料喷雾与低温燃烧的可视化研究


为了解决运输部门产生的负面环境问题，本研究致力于实现生物质燃料对石油柴油的彻底替代。在定容燃烧室中，通过光学视觉方法研究了纯生物柴油、生物柴油/乙醇混合物和两种生物柴油/乙醇/水三重微乳化燃料的喷涂、点火、燃烧和排放。首先，微乳化燃料明显提高了喷雾质量。内部水的微爆效应提高了喷雾和雾化作用，在喷雾的中后期，微乳燃料在最大水掺混比下的气液喷雾投射区域最大。其次，随着掺水比的增加，燃料的燃烧过程得到改善。火焰升空长度增加，点火延迟期延长，空气夹带效果增强。同时，燃烧火焰温度随含水率的增加而降低，实现低温燃烧。最后，微乳化燃料显著减少了烟尘排放。高含水率的微乳化燃料的总发光强度和标准化总 KLs 均最低，实现了最佳的烟尘减少效果。三重微乳化燃料作为全生物质替代燃料具有巨大潜力。