Simultaneous measurements of temperature, CO, and CO2 time-history in reacting n-heptane/O2/argon mixtures blended with diethyl ether behind reflected shock waves
Simultaneous measurements of temperature, CO, and CO2 time-history in reacting n-heptane/O2/argon mixtures blended with diethyl ether behind reflected shock waves
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DOI：
10.1016/j.combustflame.2022.112057
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发表时间：
2022-07
影响因子：
4.4
通讯作者：
Dao Zheng;D. He;Quan‐De Wang;Yanjun Ding;Zhimin Peng
中科院分区：
文献类型：
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作者：
Dao Zheng;D. He;Quan‐De Wang;Yanjun Ding;Zhimin Peng
采用激光吸收光谱法在激波管中同时测量了正庚烷/乙醚/O2/氩气混合物在富燃料（等效比φ = 1.2和2.0）氧化过程中的温度、CO和co2时程。选择CO基波段的两条过渡线（v”= 0,P8, 4.73 μm和v”= 1,R21, 4.56 μm）同时测量温度和CO时程。采用co2基波段（v3′′= 0,R88, 4.18 μm）中的一条过渡线进行co2时程测量，测量了其在1240 ~ 2600 K和0.7 ~ 3.8 bar下的吸收截面。然后开发了一个结合NUI Galway 1.1机制和DEE子机制的动力学模型（Sakai et al. 2017）。将所有测量数据与基于所提出机制和Zeng et al.（2017）机制的预测结果进行比较。两种机制都准确地预测了φ = 2.0和φ = 1.2 CO的近平衡/平台温度。然而，对于φ = 1.2，两种机制都略微高估了接近平衡的温度和二氧化碳。对于φ = 2.0，本文提出的机制能更好地预测CO平台浓度，而Zeng et al.（2017）的机制能更好地预测co2平台浓度。对气温上升和CO/ co2演化过程的预测不太准确。对于正庚烷和乙醚的特定当量比和混合比，预测也不太准确。产率分析表明，在本文条件下，HCO + M = H + CO + M是产CO的主要途径，CO + OH = CO2+ H是产CO的主要途径。敏感性分析表明，最敏感的反应是H + O2= OH + O，与axc3h55和CH3CHO相关的一些反应也影响CO和co2时程。通过修改特定反应的速率常数，可以减小预测结果与测量结果的差异，但差异仍然存在，机理有待进一步完善。
The temperature, CO, and CO2time-histories for the fuel-rich (equivalence ratio ϕ = 1.2 and 2.0) oxidation of n-heptane/diethyl ether/O2/argon mixtures were measured simultaneously in a shock tube using laser absorption spectroscopy. Two transition lines (v" = 0, P8, 4.73 μm andv" = 1, R21, 4.56 μm) in the CO fundamental band were selected to simultaneously measure the temperature and CO time-histories. One transition line in the CO2fundamental band (v3“= 0, R88, 4.18 μm) was used for the CO2time-history measurements, with its absorption cross-section measured at 1240 – 2600 K and 0.7 – 3.8 bar. A kinetic model was then developed that combined the NUI Galway 1.1 mechanism and the DEE sub-mechanism (Sakai et al. 2017). All the measured data were compared with predictions based on the proposed mechanism and the Zeng et al. (2017) mechanism.Both mechanisms accurately predicted the near-equilibrium/plateau temperatures for ϕ = 2.0 and CO for ϕ = 1.2. However, for ϕ = 1.2, both mechanisms slightly overpredict the near-equilibrium temperature and CO2. For ϕ = 2.0, the presented mechanism better predicts the CO plateau concentrations while the Zeng et al. (2017) mechanisms are better in predicting CO2plateau concentrations. The predictions were less accurate for the temperature rise and CO/CO2-evolution processes. The predictions were also less accurate for specific equivalence ratios and blending ratios of n-heptane and diethyl ether. Rate-of-production analyses showed that HCO + M = H + CO + M is the primary pathway for producing CO and CO + OH = CO2+ H is the primary pathway for producing CO2for the conditions in this manuscript. Sensitivity analyses show that the most sensitive reaction is H + O2= OH + O,with some reactions related to AXC3H5and CH3CHO also influencing the CO and CO2time-histories. Modifying the rate constants of the specific reactions reduces the differences between the predicted and measured results, but discrepancies still exist and the mechanisms need to be further improved.