摘要
选用甲醇-柴油乳化液滴和正己烷-柴油互溶液滴作为试验对象,采用飞滴式单液滴方法,研究了高温环境下燃油液滴的微爆现象及其规律.通过研究甲醇-柴油乳化液滴和正己烷-柴油互溶液滴的微爆过程,对比了互溶柴油液滴及乳化柴油液滴进行膨胀破碎的差异性,结果发现:互溶燃油液滴可观察到明显的气泡融合过程;相比于互溶燃油液滴,乳化油液滴的破碎发生更早,膨胀速率更快,但膨胀比较小.探究了甲醇体积分数和液滴初始直径对甲醇-柴油乳化油液滴微爆过程的影响发现,甲醇体积分数增加对乳化油液滴微爆起先促进后抑制的作用.随甲醇体积分数的增加,乳化油液滴的破碎时刻先提前后推迟,膨胀比先增大后减小;在甲醇体积分数为30%时,乳化油的微爆效果达到最优.最后对比了两种不同程度的微爆现象发现,整体微爆的膨胀速率和膨胀比均大于局部微爆,发生整体微爆的液滴雾化效果更好.相同条件下液滴发生不同程度微爆的原因是气泡的生成位置不同.
Methanol-diesel emulsified droplet and n-hexane-diesel miscible droplet were selected as the research objects.The free falling drop method was used to systematically study micro-explosion phenomenon and its characteristics of the fuel droplets in high temperature environment.Firstly,the expansion and breakup of the emulsified fuel and the miscible fuel during micro-explosion process in high temperature environment were compared.The results show that obvious bubble fusion process can be observed in miscible droplets.Compared to miscible droplets,the breakup of emulsified droplets occurs earlier,the expansion rate is faster,but the expansion ratio is smaller.Secondly,the influence of methanol content and initial diameter on the micro-explosion process of methanol-diesel emulsified droplets was explored.The results show that with the increase of methanol content,the micro-explosion of emulsified oil droplet is first promoted and then suppressed.With the increase of methanol content,the breakup time of emulsified droplets is first advanced and then delayed,and the expansion ratio first increases and then decreases.When the methanol volume fraction is 30%,the micro-explosion effect of the emulsified fuel reaches the best.Finally,two different degrees of micro-explosion were compared.The result shows that the expansion rate and expansion ratio of the entire micro-explosion are greater than those of the partial micro-explosion,so the atomization effect of droplets with entire micro-explosion is better.The reason for the different degrees of micro-explosion of the droplets under the same conditions is that the bubble generation positions are different.
作者
齐正达
韩恺
倪兆静
Qi Zhengda;Han Kai;Ni Zhaojing(School of Mechanics and Vehicle,Beijing Institute of Technology,Beijing 100081,China;Chongqing Innovation Center,Beijing Institute of Technology,Chongqing 401120,China)
出处
《内燃机学报》
EI
CAS
CSCD
北大核心
2022年第3期225-232,共8页
Transactions of Csice
基金
国家自然科学基金资助项目(91741121).
关键词
柴油
乳化油
飞滴
微爆
互溶燃油
diesel
emulsified fuel
free falling drop
micro-explosion
miscible fuel
