进排气全封闭内燃机富氧燃烧研究

发布时间：2018-03-23 10:31

本文选题：闭式循环　切入点：定容燃烧弹　出处：《北京建筑大学》2016年硕士论文

【摘要】：为了有效降低柴油机的排放污染物以满足其在特殊环境中的使用要求,提出了一种液氧固碳闭式循环柴油机。该类闭式循环柴油机拥有良好的应用前景,但是前期的研究工作主要集中在台架性能测试方面,对于柴油在这种新式循环背景下的着火化学反应机理方面的研究比较欠缺,因此急需在着火燃烧方面的进行深入研究。利用流体动力学计算软件KIVA-3V建立了以Sandia定容燃烧弹为原型的计算网格,仿真了柴油在O_2/CO_2背景气体下的燃烧特性,并利用色温法对比了仿真结果与试验结果,验证了计算模型的准确性。利用了定容燃烧弹测试平台对试验过程进行了可视化研究,试验分工况研究了不同进气成分背景条件下对柴油喷雾以及着火燃烧特性的影响规律。应用CCD高速摄影机对试验过程及结果进行了记录。最后对不同燃烧阶段所得数据进行了相关分析,得出结论。研究发现,背景气体成分的变化会引起其密度的变化;背景气体为空气时密度最低,当成分变为50%氧气与50%二氧化碳混合时密度最高。背景气体的密度会对燃油液相喷雾的贯穿距离产生较大影响,但对其液相锥角的影响不大。其次,随着进气成分中氧浓度的升高,二氧化碳量的下降,滞燃期迅速缩短,着火点位置离喷油孔的距离逐渐减小。
[Abstract]:In order to effectively reduce the emission of pollutants from diesel engine to meet the requirements of its application in special environment, a liquid-oxygen solid carbon closed cycle diesel engine is proposed. This type of closed cycle diesel engine has a good application prospect. However, the previous research work is mainly focused on the bench performance test, and the research on the ignition chemical reaction mechanism of diesel oil under this new cycle background is relatively lacking. Therefore, it is urgent to make a deep research on ignition combustion. Using the hydrodynamic calculation software KIVA-3V, a computational grid based on Sandia constant volume combustor is established, and the combustion characteristics of diesel oil under the background gas of O_2/CO_2 are simulated. The accuracy of the calculation model is verified by comparing the simulation results with the experimental results by using the color temperature method, and the visual research on the test process is carried out by using the constant volume combustion bomb test platform. The effects of different inlet air components on diesel spray and ignition characteristics were studied in different operating conditions. The experimental process and results were recorded by using CCD high speed camera. Finally, different combustion stages were studied. The data were analyzed. Conclusion. The study found that changes in the composition of background gases cause changes in their density; when background gases are air, the density is the lowest, When the composition is mixed with 50% oxygen and 50% carbon dioxide, the density of the background gas will have a great effect on the penetration distance of the fuel liquid spray, but not on the liquid cone angle. With the increase of oxygen concentration, the amount of carbon dioxide decreases, the ignition delay period shortens rapidly, and the distance from the injection hole decreases gradually.
【学位授予单位】：北京建筑大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TK421.2

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