小尺度乳化柴油池火的沸腾燃烧特性实验研究

Experimental study of boiling characteristics in a small emulsified diesel pool fire

使用乳化柴油是实现发动机节油减排的重要方式,而含水率是影响乳化柴油燃烧效率的关键因素。为了预防乳化柴油泄漏火灾并减少人员伤亡和财产损失,该文采用直径为150 mm的不锈钢油盘,实验研究了含水率分为0%、 5%、 10%、 15%和20%的油包水(W/O)型乳化柴油池火的燃烧和沸腾特性。根据燃烧速率和火焰高度的变化情况,将乳化柴油燃烧过程划分为初始增长阶段、沸腾燃烧阶段、脉动阶段、稳定燃烧阶段和熄灭阶段,其中前3个阶段的燃烧有水参与,而后2个阶段的燃烧特性与0#柴油池火的稳定燃烧阶段和熄灭阶段基本一致。随着含水率的增加,沸腾燃烧阶段和脉动阶段的时间呈“增加—稳定—增加”的趋势,而稳定燃烧阶段的时间呈“减少—稳定—减少”的趋势。乳化柴油池火燃烧过程出现了沸腾燃烧并导致火焰高度下降现象。该研究有助于乳化柴油泄漏火灾的风险评估。

The use of emulsified diesel fuel in internal combustion engines reduces fuel consumption and engine emissions. The water content is a key factor affecting the combustion efficiency of emulsified diesel fuels. The combustion and boiling characteristics of emulsified diesel fuel pool fires were studied here using a 150 mm diameter stainless steel tray to find ways to reduce casualties and property losses. The water contents of the emulsified diesel fuels were 0 %, 5 %, 10 %, 15 % and 20 %. The combustion characteristics of the emulsified diesel fuel pool fires were divided into the initial growth stage, boiling combustion stage, pulsation stage, stable combustion stage and extinguishing stage based on the variations of the burning rate and the flame height. The combustion characteristics during the first three stages were affected by the water content while the combustion characteristics during the final two stages were similar to those of pure diesel fuel fires. Increasing the water content caused the durations of the boiling combustion stage and the pulsation stage to first become longer, then become stable and then become longer again while the duration of the stable combustion stage first decreased, then became stable and then decreased again with increasing water content. Boiling combustion occurs during emulsified diesel fuel pool fires which wakes the flame heights decrease. This study will help risk assessments of emulsified diesel fuel fires.