Cell formation effects on the burning speeds and flame front area of synthetic gas at high pressures and temperatures
Cell formation effects on the burning speeds and flame front area of synthetic gas at high pressures and temperatures
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DOI：
10.1016/j.apenergy.2016.12.090
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发表时间：
2017-03
期刊：
影响因子：
11.2
通讯作者：
Omid Askari;M. Elia;M. Ferrari;H. Metghalchi
中科院分区：
文献类型：
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作者：
Omid Askari;M. Elia;M. Ferrari;H. Metghalchi
在与发动机相关的条件下，在高压和温度下，测定了预混合成气/氧化剂/稀释剂（H2/CO/O2/He）的细胞燃烧速度和质量燃烧速率。研究高压燃烧有助于减少污染，提高燃烧装置的能源效率。实验装置由两个球形和圆柱形室组成。球形燃烧室可承受高达400atm的高压，用于收集燃烧引起的压力上升数据，计算细胞燃烧速度和质量燃烧速率。利用高速CMOS相机和纹影摄影系统，利用圆柱腔对火焰的传播过程进行拍摄，对火焰的结构和不稳定性进行了分析。采用一种基于压力上升数据的差分多壳模型来确定细胞燃烧速度和质量燃烧速率。本文测量了H2/CO/O2/He混合物的细胞燃烧速度和质量燃烧速率，其当量比为0.6 ~ 2，温度为400 ~ 750k，压力为2 ~ 50atm，氢气浓度分别为5、10和25%。建立了细胞燃烧速度和质量燃烧速度的幂律相关关系，作为等效比、温度和压力的函数。本研究引入了一个新的参数——细胞因子，它反映了细胞的形成对火焰表面积和燃烧速度的影响。结合实验压力数据建立的多壳模型和详细化学机理的自由平面火焰模拟，计算了合成气在高压和高温下的火焰总表面积和细胞因子。结果表明，细胞因子与压力、当量比、氢浓度呈正相关，与温度负相关。
Cellular burning speeds and mass burning rates of premixed syngas/oxidizer/diluent (H2/CO/O2/He) have been determined at high pressures and temperatures over a wide range of equivalence ratios which are at engine-relevant conditions. Working on high pressure combustion helps to reduce the pollution and increase the energy efficiency in combustion devices. The experimental facilities consisted of two spherical and cylindrical chambers. The spherical chamber, which can withstand high pressures up to 400 atm, was used to collect pressure rise data due to combustion, to calculate cellular burning speed and mass burning rate. For flame structure and instability analysis the cylindrical chamber was used to take pictures of propagating flame using a high speed CMOS camera and a schlieren photography system. A new differential based multi-shell model based on pressure rise data was used to determine the cellular burning speed and mass burning rate. In this paper, cellular burning speed and mass burning rate of H2/CO/O2/He mixture have been measured for a wide range of equivalence ratios from 0.6 to 2, temperatures from 400 to 750 K and pressures from 2 to 50 atm for three hydrogen concentrations of 5, 10 and 25% in the syngas. The power law correlations for cellular burning speed and mass burning rate were developed as a function of equivalence ratio, temperature and pressure. In this study a new developed parameter, called cellularity factor, which indicates the cell formation effect on flame surface area and burning speed has been introduced. The total flame surface area and cellularity factor for syngas at high pressures and temperatures have been calculated by combining the multi-shell model via the experimental pressure data with free flat flame simulation using detailed chemical mechanism. The results show that the cellularity factor has a positive relation to pressure, equivalence ratio and hydrogen concentration while it has a negative dependency to temperature.