燃烧油滴内部蒸发的气泡周期性暴涨/碎裂

Periodic expansion/fracture of bubbles in burning oil droplets by internal evaporation

利用高速显微摄像技术捕捉到航空煤油RP-3挂滴的燃烧现象——微气泡周期性暴涨/破碎现象。环境温度为973K时,在直径为1.25mm的燃烧油滴内,捕捉到了微气泡的急剧暴涨和瞬间碎裂现象。即:(1)在0.04s内,微气泡直径增长41.6%;(2)在0.01s内,暴涨的气泡在油滴内破碎,激发油滴急剧振荡;(3)油滴恢复相对稳定的蒸发燃烧,内部残留的微气泡,启动第2轮暴涨/破碎;(4)经过3轮暴涨/破碎,油滴燃烧殆尽。因而得出:被高温加热的石英丝挂钩在油滴内部诱发的快速蒸发效应,是微气泡周期性暴涨/碎裂的驱动力,而表面张力则是油滴恢复并保持稳定燃烧的约束机制。

The following phenomena were captured in combustion process by highspeed microscopic camera technology：the periodic expansion/fracture of micro bubbles in aviation kerosene RP-3 suspended droplet.The phenomena that the micro bubbles sharply expanded and suddenly fractured were found inside the burning 1.25 mm diameter droplet at environment temperature of 973 K.Namely：（1） in 0.04 s,the diameter of the micro bubbles increased by 41.6%;（2） in 0.01s,the expansion bubble was fractured inside the droplet,which stimulated the droplet＇s sharply oscillations;（3） the droplet resumed relatively stable evaporation and combustion,and the internal residuals of the micro bubbles were observed to start the second round of expansion/fracture;（4） the droplet burned away after three rounds of expansion/fracture.The following mechanism was speculated：the quartz fiber heated by high temperature induced the rapid evaporation effect inside the droplet,which was the driving force of the micro bubble periodic expansion/fracture.Moreover,surface tension was the restraint mechanism to restore and maintain the droplet stable comhustion.