An experimental investigation of flame and autoignition behavior of propane
An experimental investigation of flame and autoignition behavior of propane
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DOI：
10.1016/j.combustflame.2020.12.001
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发表时间：
2021-02
影响因子：
4.4
通讯作者：
M. Burnett;M. Wooldridge
中科院分区：
文献类型：
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作者：
M. Burnett;M. Wooldridge
自燃延迟时间数据是发展、量化和验证低温（T<1200 K）燃烧化学基本认识的重要手段。然而，与高温点火数据（T>1200 K）相比，低温化学实验数据往往具有更高的不确定性和分散性。在这项研究中，自燃性能的丙烷和氧气的混合物进行了研究，使用密歇根大学的快速压缩设施，以了解点火制度的影响，低温点火数据。对于丙烷的第一次，自燃延迟时间从压力的历史，并同时记录自燃特性使用高速成像的测试部分通过一个透明的端壁。在8.9 ~ 11.3atm和930 ~ 1070 K的压力范围内，研究了燃料与氧当量比分别为0.25和0.5，氧与惰性气体摩尔比为1：3.76的丙烷混合物的燃烧特性。结果表明，均质或强烈的自燃发生的所有实验的ε = 0.25，和非均质或混合自燃发生的所有ε = 0.5的实验。虽然在研究中涵盖了有限的温度范围，但重要的是，数据跨越了自燃行为的预测转变，从而验证了自燃机制假设。具体而言，结果同意强自燃极限提出的Sankaran准则的基础上。在强点火条件下的自燃延迟时间数据与使用文献中经过充分验证的详细反应机制和零维建模假设的预测非常一致。然而，在混合自燃条件下的实验数据系统快于模型预测，特别是在较低的温度（T< ~970 K）。结果是一个重要的除了在文献中，显示混合自燃现象的数据越来越多的重要来源，在丙烷和其他燃料的低温自燃数据中观察到的更高的分散。结果进行了讨论，在不同的方法来捕捉与混合自燃条件下的自燃前的热释放的影响，从而解决一些动力学建模和实验测量之间的差异。
Autoignition delay time data are one important means to develop, quantify, and validate fundamental understanding of combustion chemistry at low temperatures (T<1200 K). However, low-temperature chemistry often has higher uncertainties and scatter in the experimental data compared with high-temperature ignition data (T>1200 K). In this study, autoignition properties of propane and oxygen mixtures were investigated using the University of Michigan rapid compression facility in order to understand the effects of ignition regimes on low-temperature ignition data. For the first time for propane, autoignition delay times were determined from pressure histories, and autoignition characteristics were simultaneously recorded using high-speed imaging of the test section through a transparent end-wall. Propane mixtures with fuel-to-O2equivalence ratios of ϕ = 0.25 and ϕ = 0.5 and O2-to-inert gas molar ratios of 1:3.76 were studied over the pressure range of 8.9 to 11.3 atm and the temperature range of 930 – 1070 K. The results showed homogeneous or strong autoignition occurred for all ϕ = 0.25 experiments, and inhomogeneous or mixed autoignition occurred for all ϕ = 0.5 experiments. While a limited temperature range is covered in the study, importantly the data span predicted transitions in autoignition behavior, allowing validation of autoignition regime hypotheses. Specifically, the results agree well with strong-autoignition limits proposed based on the Sankaran Criterion. The autoignition delay time data at the strong-ignition conditions are in excellent agreement with predictions using a well-validated detailed reaction mechanism from the literature and a zero-dimensional modeling assumption. However, the experimental data at the mixed autoignition conditions were systematically faster than the model predictions, particularly at lower temperatures (T< ~970 K). The results are an important addition to the growing body of data in the literature that show mixed autoignition phenomena are important sources of the higher scatter observed in the low-temperature autoignition data for propane and other fuels. The results are discussed in terms of different methods to capture the effects of pre-autoignition heat release associated with mixed autoignition conditions and thereby address some of the discrepancies between kinetic modeling and experimental measurements.