汽油层流燃烧速度的测量及其替代物模型研究

Research on the Laminar Burning Velocity and Surrogate Models of Gasoline

针对实际汽油组分复杂导致数值模拟研究困难的问题,采用球形火焰法,在定容燃烧弹上测量了初始温度分别为358、403、448 K,初始压力分别为0.1、0.2、0.5 MPa,当量比为0.8～1.5工况下,实际汽油、正庚烷、异辛烷、甲苯、异辛烷/正庚烷混合燃料(PRF)、甲苯/异辛烷/正庚烷混合燃料(TRF)的层流燃烧速度,分析了初始温度、压力以及当量比对汽油的层流燃烧速度的影响规律,对比了不同替代物模型对实际汽油的层流燃烧速度的预测结果。基于实验结果,构建了适合我国汽油的双组分和三组分汽油替代物模型,对比结果表明,在本研究的实验工况范围内,三组分汽油替代物模型比双组分汽油替代物模型能够更好预测实际汽油层流燃烧速度。应用Chemkin软件和KAUST清洁燃烧研究中心近期发展的汽油替代物机理,对本研究实验数据进行了数值仿真,该机理对实验数据给出了合理预测。利用本研究提出的汽油替代物模型,可对实际汽油的层流燃烧速度进行合理的预测。

The spherical flame method was adopted for the problem that numerical simulation research is somewhat difficult due to the complexity of the actual gasoline composition. Laminar burning velocities of actual gasoline were measured in a constant volume bomb. Measurements were also conducted for n-heptane, iso-octane, primary reference fuels (n-heptane and iso-octane blends), and toluene reference fuel (n-heptane, iso-octane and toluene blends). Experiments were performed at the equivalence ratios from 0.8 to 1.5, initial temperatures of 358, 403 and 448 K and pressures of 0.1, 0.2 and 0.5 MPa, respectively. The effects of initial temperature, pressure and equivalence ratio on laminar burning velocity were analyzed. Based on the experimental results, primary reference fuel surrogate model (PRF) and toluene reference fuel surrogate model (TRF) were proposed. The results showed that the TRF model could better predict the laminar burning velocity of actual gasoline than the PRF model. Besides, using the software CHEMKIN and the KAUST Clean Combustion Research Center’s recently developed gasoline surrogate, numerical simulation of the measured data was carried out, which gives a reasonable prediction of the measured data under the research conditions. Therefore, a reasonable numerical simulation study on actual gasoline could be carried out by using the gasoline surrogate model proposed in this study.