乙醇添加比例对乙醇-柴油混合物表面火蔓延的影响研究

实时记录了不同比例乙醇柴油混合燃料的火蔓延过程,对蔓延火焰的外貌结构、火蔓延模式、火蔓延速度以及油面温升规律等进行了探讨。研究发现,当乙醇添加比例10%时,混合燃料火焰低速脉动蔓延,火焰前锋油面下方存在表面流,火蔓延速度变化幅度比较小,燃料表面的升温速率随初温的升高而升高;当乙醇添加比例≥10%时,火焰稳定蔓延,表面流消失,火蔓延速度会随着燃料初温的升高而降低,燃料表面的升温速率随初温的升高而降低。

Effect of ethanol proportion on the surface flame spread of ethanol-diesel mixture

The effect of ethanol proportion on the surface flame spread of ethanol-diesel mixture was investigated by experiments. The flame structure and the surface flame spread mode were analyzed. The temperature rise of the liquid surface and the flame spread rate were discussed. The results showed that the flame of the ethanol-diesel mixture spread with low speed pulsation when the add proportion of ethanol was less than 10%, for which the flame spread rate showed a relatively small amplitude of variation. Meanwhile, surface flow appeared under the oil surface of the flame front and the heating rate of the mixed fuel surface increased with increasing initial temperature. As the proportion of ethanol was over 10%, the flame spread became steady and the surface flow disappeared. In addition, both the flame spread rate and the heating rate of the mixed fuel surface decreased with the increase of initial temperature.