Multi-stage oxidation of a CH2F2/air mixture examined by weak flames in a micro flow reactor with a controlled temperature profile
Multi-stage oxidation of a CH2F2/air mixture examined by weak flames in a micro flow reactor with a controlled temperature profile
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在具有受控温度分布的微流反应器中通过弱火焰检查 CH2F2/空气混合物的多级氧化
DOI：
10.1016/j.combustflame.2018.12.014
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发表时间：
2019
影响因子：
4.4
通讯作者：
K. Maruta
中科院分区：
文献类型：
--
作者：
Shintaro Takahashi;H. Nakamura;T. Tezuka;S. Hasegawa;K. Maruta
使用具有受控温度曲线 (MFR) 的微流反应器对广泛使用的制冷剂 CH2F2(R32) 的氧化进行了实验和计算研究。具体来说，我们检查了在低流速下观察到的 MFR 中化学计量 CH2F2/空气混合物的弱火焰。在最高壁温为1300K的情况下，弱火焰在1240和1290K处出现两个发光区域，这意味着两阶段氧化。计算还表明有两阶段的热量释放。计算出的弱火焰位置也与实验获得的结果非常吻合。为了详细评估化学动力学的有效性，使用傅里叶变换红外光谱 (FTIR) 对化学计量 CH2F2/空气弱火焰的 CH2F2、CO、CO2、H2O、HF 和 CF2O 进行了物种测量。目前的物质测量阐明了 800–1300K 下的 CH2F2/空气弱火焰结构以及反应器末端剩余的 H2O 和 CF2O 中间体。计算结果也显示出与测量的良好一致性，表明使用化学动力学计算的有效性。为了进一步分析 1300K 的 CH2F2 弱火焰，反应路径和产率分析揭示了第一阶段放热的主要反应：HF 和中间体的形成，第二阶段是 CO 形成 CO2。计算还表明 H2O 和 CF2O 中间体残留在反应器末端。在最高壁温 2000K 下对 CH2F2/空气混合物进行的附加数值实验表明，在高于 1300K 的温度下，H2O 和 CF2O 的反应缓慢进行，CH2F2/空气混合物完全氧化。总之，结果表明，如果氧化发生在非绝热系统（如 MFR）中，则由于 CF2O 和 H2O 等低反应性中间体，CH2F2 的整体反应性会降低。 CH2F2/空气混合物的这种特定特性隐藏在常见的零维绝热模拟中。结果表明，CH2F2 反应性强烈依赖于氧化过程中的温度历史。
Oxidation of CH2F2(R32), a widely used refrigerant, was investigated experimentally and computationally using a micro flow reactor with a controlled temperature profile (MFR). Specifically, we examined weak flames of a stoichiometric CH2F2/air mixture in MFR observed at low flow velocities. In the case of the maximum wall temperature of 1300 K, weak flames showed two luminous regions at 1240 and 1290 K, implying two-stage oxidation. Computations also indicated two-stage heat release. Computational weak flame positions also showed good agreement with experimentally obtained results. To assess the validity of chemical kinetics in detail, species measurements of CH2F2, CO, CO2, H2O, HF, and CF2O for a stoichiometric CH2F2/air weak flame were conducted using Fourier Transform Infrared spectrometry (FTIR). The present species measurements elucidated the CH2F2/air weak flame structure at 800–1300 K and remaining intermediates of H2O and CF2O at the end of the reactor. Computational results also showed good agreements with measurement, indicating the validity of the computations using the chemical kinetics. For further analysis for CH2F2weak flame at 1300 K, the reaction path and rate-of-production analyses revealed a major reaction at the first-stage heat release: the formation of HF and intermediates, and that at the second stage is the CO2formation from CO. Computations also showed intermediates of H2O and CF2O remain at the end of the reactor. An additional numerical experiment for a CH2F2/air mixture at the maximum wall temperature of 2000 K, demonstrated that the reaction of H2O and CF2O proceeded slowly at temperatures higher than 1300 K, with complete oxidation of CH2F2/air mixture. In conclusion, results show that the overall reactivity of CH2F2decreases because of the low reactivity intermediates such as CF2O and H2O if oxidation occurs in a non-adiabatic system such as MFR. Such specific characteristics of the CH2F2/air mixture are concealed in the common zero-dimensional adiabatic simulations. Results demonstrated that the CH2F2reactivity depend strongly on the temperature history during oxidation.
影响因子：
4.4
作者：
T. Kamada;H. Nakamura;T. Tezuka;S. Hasegawa;K. Maruta
通讯作者：
T. Kamada;H. Nakamura;T. Tezuka;S. Hasegawa;K. Maruta