汽油掺氢层流预混火焰燃烧特性研究

发布时间：2018-01-16 09:25

本文关键词：汽油掺氢层流预混火焰燃烧特性研究　出处：《北京理工大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着当今社会对能源的需求量与日俱增,寻找可用的替代燃料已经迫在眉睫。氢气是一种可再生的绿色能源,与其他代用燃料相比,氢气的分子中不含有碳原子,所以氢气在燃烧时不会产生碳排放,仅有的有毒排放物为NOx。但从目前的技术角度来看,受到制氢成本昂贵,加氢的基础设施不完善,以及氢气的存储问题,尚不具备大规模使用纯氢内燃机的现实条件。当前社会,汽油作为乘用车的主要燃料,尚不能被完全替代,因此通过汽油掺氢混合燃料的方式来缓解化石燃料的需求,是当下最切实可行的方法。因此,有必要对汽油掺氢燃烧的机理和规律进行研究。本文在定容燃烧弹上利用纹影系统对汽油掺氢预混层流燃烧球形火焰的燃烧和着火特性进行研究,通过改变当量比、掺氢比,获取火焰的纹影图片,用Matlab数字图像处理技术进行图像处理,结合两种拟合方法对比分析火焰传播速率、层流火焰燃烧速率、Markstein长度等相关表征燃烧特性的参数以及汽油掺氢稀燃极限的变化规律。分析表明,非线性外推法较线性外推法有较高的数据拟合精度,更适用于拉伸对火焰传播速度影响较大时。随着掺氢比的增加,汽油掺氢燃烧的拉伸火焰传播速率逐渐增加;同一掺氢比下马克斯坦长度随着当量比增大而减小,火焰层流燃烧速率随着当量比增加先增大后减小,并向偏浓混合气的方向移动。掺氢也拓展了汽油燃烧的稀燃极限。
[Abstract]:With the increasing demand for energy in today's society, it is urgent to find alternative fuels. Hydrogen is a renewable green energy, compared with other alternative fuels. There are no carbon atoms in the molecules of hydrogen, so hydrogen does not emit carbon when it burns. The only toxic emission is no x. but from the current technical point of view, the cost of hydrogen production is expensive. The infrastructure of hydrogenation is not perfect, and the storage of hydrogen does not have the practical conditions for large-scale use of hydrogen combustion engines. At present, gasoline, as the main fuel for passenger cars, can not be completely replaced. Therefore, it is the most feasible way to reduce the demand of fossil fuels by mixing gasoline with hydrogen. It is necessary to study the mechanism and regularity of gasoline hydrogen combustion. In this paper, the combustion and ignition characteristics of gasoline-doped premixed laminar combustion spherical flame are studied by using a grain shadow system on a constant volume combustion bomb. By changing the equivalent ratio and the hydrogen ratio, the flame image was obtained, and the flame propagation rate was analyzed by using Matlab digital image processing technology and two fitting methods. The combustion rate and Markstein length of laminar flame are related to the parameters of combustion characteristics and the variation law of the limit of gasoline-fueled lean combustion. The nonlinear extrapolation method has higher data fitting accuracy than linear extrapolation method, which is more suitable for drawing with the increase of hydrogen doping ratio. The flame propagation rate of gasoline mixed with hydrogen increased gradually. At the same hydrogen doping ratio, the length of Markstein decreases with the increase of equivalent ratio, and the combustion rate of laminar flow increases first and then decreases with the increase of equivalent ratio. It also extends the lean combustion limit of gasoline combustion.
【学位授予单位】：北京理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TK16

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