魏涛，郭建军，邬斌扬，苏万华.柴油机进气掺混低浓度甲烷模拟研究[J].内燃机工程,2021,42(1):34-39.
柴油机进气掺混低浓度甲烷模拟研究
Performance Simulation of Diesel Engine Intake Blended with Low Concentration Methane
DOI：10.13949/j.cnki.nrjgc.2021.01.006
关键词:柴油机  甲烷  燃烧特性  排放特性  模拟
Key Words:diesel engine  methane  combustion characteristic  emission characteristic  simulation
基金项目:国家电网公司科技项目（52130N18001G）
作者单位
魏涛，郭建军，邬斌扬，苏万华 天津大学 内燃机燃烧学国家重点实验室，天津 300072 
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摘要:针对矿井下空气中含有甲烷气体造成柴油机在矿井下运行时会吸入甲烷的情况，使用三维计算流体动力学（CFD）软件CONVERGE模拟柴油机进气混掺0%、0.25%、0.50%、0.75%与1.00%体积浓度的甲烷气体对柴油机燃烧及排放的影响。研究结果发现，当甲烷着火时刻温度大于1000K时，甲烷的掺混会使得羟基（OH）基团增多，对柴油机的燃烧起着促进作用。在柴油机1200r/min、80%负荷的工况点下，随着甲烷体积浓度提高至100%，滞燃期从7.35°缩短至7.07°，缸内最大燃烧压力从16.05MPa升高至16.46MPa，放热率峰值升高9.1%，缸内最高温度从1737K升高至1771K，NOx排放由10.55g/（kW·h）升高至11.36g/（kW·h），CO排放由0.12g/（kW·h）升高至1.34g/（kW·h），碳烟排放由1.210mg/（kW·h）下降至0.785mg/（kW·h）。矿井下空气中存在甲烷会对柴油机的燃烧及排放产生影响，但矿井下甲烷体积分数普遍低于0.7%，因此其对柴油机的影响较小。
Abstract:In order to improve the operating safety of diesel engines in methane-rich mines, three-dimensional computational fluid dynamics (CFD) software, CONVERGE， was used to simulate the influence of diesel engine intake blended with different volume concentrations of methane on engine performance and emissions. Results show that when the temperature of methane on fire is greater than 1000K, the blending of methane will increase the number of hydroxyl (OH) groups, which can promote the combustion of diesel engines. When the engine is running at 1200r/min and with 80% load, increasing the methane blending ratio to a volume concentration of 1.00% can shorten the ignition delay period from 7.35° in crank angle to 7.07° in crank angle, and increase the peak heat release rate by 0.1%, resulting in the maximum combustion pressure in the cylinder increased from 16.05MPa to 16.45MPa, and the maximum combustion temperature risen from 1737K to 1771K. For exhaust emissions, the use of methane increases NOx emission from 10.55g/(kW·h) to 11.36g/(kW·h) and hence CO emission from 0.12g/(kW·h) to 1.34g/（kW·h）, but soot emissions can be decreased from 1.21×10-3g/(kW·h) to 7.85×10-4g/(kW·h). Considering that the volume concentration of methane in the air of mines is generally less than 0.7%, so it has little influence on operating safety of diesel engines.
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