Studying pure ethanol spray flame has the potential to achieve the carbon neutrality vision. This paper studies the effects of fuel injection masses (12, 24, 36 mg) and fuel injection pressures (30, 40, 50 MPa) on ethanol spray flame on an optically visualized constant volume combustion chamber. Further compared with the spray flame of methanol and n-butanol. The combustion characteristics and flame development process were revealed by flame self-illumination high-speed imaging method, and the soot distribution was revealed by wavelength integration two-color method. Results show that ethanol spray flame presents an unstable yellow flame with many wrinkles. Small injection masses exist a partial flame-quenching phenomenon. As injection mass increases, the soot lift-off length decreases, and the flame brightness, soot concentration, and ignition delay increase. The high soot concentration areas locate upstream of the flame, and there is almost no soot downstream. Increased injection pressure increases the soot lift-off length and decreases the flame brightness. The ignition delay is shortened from 8.388 ms to 6.955 ms when injection pressure increases from 30 MPa to 40 MPa. But higher injection pressure has a negligible effect on reducing ignition delay. Finally, an ethanol spray combustion conceptual model is proposed. This paper gives particular guiding significance to the future use of carbon-neutral ethanol in diesel engines.

研究纯乙醇喷雾火焰有可能实现碳中和的愿景。本文研究了光学可视化定容燃烧室中燃料喷射质量（12、24、36 mg）和燃料喷射压力（30、40、50 MPa）对乙醇喷雾火焰的影响。进一步与甲醇和正丁醇的喷雾火焰进行比较。采用火焰自发光高速成像方法揭示燃烧特性和火焰发展过程，采用波长积分二色法揭示烟灰分布。结果表明，乙醇喷雾火焰呈不稳定的黄色火焰，有很多皱纹。小喷射量存在局部熄火现象。随着喷射质量的增加，烟灰升离长度减小，火焰亮度、烟灰浓度、和点火延迟时间增加。烟尘浓度高的区域位于火焰上游，下游几乎没有烟尘。增加喷射压力会增加烟灰升离长度并降低火焰亮度。当喷射压力从30 MPa增加到40 MPa时，着火延迟期从8.388 ms缩短到6.955 ms。但较高的喷射压力对于减少点火延迟的影响可以忽略不计。最后，提出了乙醇喷雾燃烧概念模型。该论文对于未来在柴油发动机中使用碳中性乙醇具有特别的指导意义。当喷射压力从30 MPa增加到40 MPa时，着火延迟期从8.388 ms缩短到6.955 ms。但较高的喷射压力对减少点火延迟的影响可以忽略不计。最后，提出了乙醇喷雾燃烧概念模型。该论文对于未来在柴油发动机中使用碳中性乙醇具有特别的指导意义。当喷射压力从30 MPa增加到40 MPa时，着火延迟期从8.388 ms缩短到6.955 ms。但较高的喷射压力对于减少点火延迟的影响可以忽略不计。最后，提出了乙醇喷雾燃烧概念模型。该论文对于未来在柴油发动机中使用碳中性乙醇具有特别的指导意义。