Effects of buffer gas composition on low temperature ignition of iso-octane and n-heptane
Effects of buffer gas composition on low temperature ignition of iso-octane and n-heptane
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缓冲气体组成对异辛烷和正庚烷低温着火的影响
DOI：
10.1016/j.combustflame.2014.04.014
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发表时间：
2014-10
影响因子：
4.4
通讯作者：
Jianxin Wang
中科院分区：
文献类型：
--
作者：
Haisheng Di;Xin He;Peng Zhang;Zhi Wang;Margaret S. Wooldridge;Chung K. Law;Cuiping Wang;Shijin Shuai;Jianxin Wang
本文通过实验和数值模拟研究了缓冲气体组分对异辛烷和正庚烷低温着火的热力学和化学效应。在600-850 K温度范围内，使用最近开发的快速压缩机进行实验。研究了三种缓冲气体，包括氮气（N2），氩气（Ar），和Ar和二氧化碳（CO2）的混合物的摩尔比为65.1%/34.9%。异辛烷在20巴，N2 = 1，缓冲气体与O2的稀释度为3.76：1（摩尔比）下进行了研究。正庚烷在9巴，λ = 1，缓冲气体与O2的稀释度为5.63：1（摩尔比）下进行了研究。对于观察到两阶段点火的实验，缓冲气体组合物对第一阶段点火时间没有影响，但正如预期的那样，它导致第一阶段点火后总放热、压力和温度升高的差异。因此，观察到显着差异的总点火延迟时间作为缓冲气体组合物的函数，与高达40%和42.5%的总点火时间快异辛烷和正庚烷，分别通过使用Ar而不是N2。通过比较N2和Ar/CO2（65.1%/34.9%）混合物的结果，实验研究了缓冲气体组合物的化学效应，认识到虽然Ar/CO2混合物具有与N2相同的热容，但其预测的组合第三体碰撞效率比N2高约76%。实验结果表明，化学影响的第一阶段和总点火延迟时间可以忽略不计。在较宽的温度范围内进行了纯N2，Ar和CO2作为缓冲气体的数值模拟。结果表明，在负温度系数和两阶段点火条件下，热效应非常明显，并占主导地位，这与实验结果和文献中的研究结果一致。然而，模拟结果也表明，在温度高于850 K，CO2的化学效应变得比热效应更重要。
Experimental and numerical studies have been performed on the thermal and chemical effects of buffer gas composition on low temperature ignition of iso-octane and n-heptane. Experiments were conducted using a recently developed rapid compression machine in the temperature range of 600–850 K. Three buffer gases were studied including nitrogen (N2), argon (Ar), and a mixture of Ar and carbon dioxide (CO2) at a mole ratio of 65.1%/34.9%. Iso-octane was studied at 20 bar,ϕ= 1, and a dilution level of buffer gas to O2of 3.76:1 (mole ratio). n-Heptane was studied at 9 bar,ϕ= 1, and a dilution level of buffer gas to O2of 5.63:1 (mole ratio). For experiments where two-stage ignition was observed, the buffer gas composition had no impact on the first-stage ignition time but, as expected, it caused differences in the total heat release, pressure and temperature rise after the first-stage ignition. As a consequence, significant differences were observed for the total ignition delay time as a function of the buffer gas composition, with up to 40% and 42.5% faster total ignition time for iso-octane and n-heptane, respectively, by using Ar instead of N2. The chemical effects of the buffer gas composition were studied experimentally by comparing the results of the N2and Ar/CO2(65.1%/34.9%) mixtures, recognizing that while the Ar/CO2mixture has the same heat capacity as N2, its predicted combined third-body collision efficiency is about 76% higher than N2. The experimental results showed negligible chemical effects on the first-stage and total ignition delay times. Numerical simulations were carried out over a wider range of temperatures for pure N2, Ar, and CO2as buffer gases. Results showed that thermal effects are very pronounced and dominated at the negative temperature coefficient and two-stage ignition conditions, which is consistent with the experimental results and previous studies in the literature. However, the simulation results also showed at temperatures higher than 850 K, the chemical effects of CO2became more important than the thermal effects.
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影响因子：
4.4
作者：
J. Würmel;E. Silke;H. Curran;M. Ó. Conaire;J. Simmie
通讯作者：
J. Würmel;E. Silke;H. Curran;M. Ó. Conaire;J. Simmie
影响因子：
1.5
作者：
Davidson, DF;Hanson, RK
通讯作者：
Hanson, RK
DOI：
10.1016/s0082-0784(96)80098-1
发表时间：
1996
期刊：
--
影响因子：
--
作者：
N. Hadjiconstantinou;K. Min;J. Heywood
通讯作者：
N. Hadjiconstantinou;K. Min;J. Heywood
影响因子：
4.4
作者：
H. Machrafi;S. Cavadias;P. Guibert
通讯作者：
H. Machrafi;S. Cavadias;P. Guibert
影响因子：
1.9
作者：
Gaurav Mittal;C. Sung
通讯作者：
Gaurav Mittal;C. Sung