Flame extinction limits in CH2F2/air mixtures
Flame extinction limits in CH2F2/air mixtures
复制标题
CH2F2/空气混合物中的火焰熄灭极限
DOI：
10.1016/s0010-2180(98)00138-2
复制
发表时间：
1999
影响因子：
4.4
通讯作者：
W. Grosshandler
中科院分区：
文献类型：
--
作者：
C. Womeldorf;W. Grosshandler
为了优化非臭氧消耗制冷剂替代品混合物的效率和安全性，精确测量纯制冷剂的贫燃极限及其混合物的临界可燃比至关重要。当前模拟一定量预混合燃料和空气的意外点燃的测试方法在测量弱可燃制冷剂的极限行为时提供了不明确的结果。已经测试了另一种方法，该方法使用在预混合逆流燃烧器中测量的全局消光拉伸率外推至零。在这项工作中，介绍了该技术应用于 CH2F2（二氟甲烷，R-32）的方法、准确性和精密度。对同一燃烧器中 CH4 的行为以及已发表的稀薄极限当量比 Φ0 数据进行了比较。 CH2F2 在干燥空气中的贫燃极限为 Φ0= 0.78 ± 0.04。对空气中 CH2F2 单独燃烧以及与 CH4 混合的一维无应变火焰的燃烧进行了并行计算建模。报告了 CH2F2/空气混合物从化学计量到稀薄层流火焰速度的初步估计，并根据实验结果进行了解释。
To optimize the efficiency and safety of mixtures of nonozone-depleting refrigerant replacements, precise measurements of the lean flammability limits of pure refrigerants and the critical flammability ratio of their mixtures are crucial. Current test methods that model the accidental ignition of a volume of premixed fuel and air provide ambiguous results when measuring the limiting behavior of weakly flammable refrigerants. An alternative approach using the extrapolation of the global extinction stretch rates to zero as measured in a premixed counterflow burner has been tested. In this work the approach, accuracy, and precision of the technique as it applies to CH2F2(difluoromethane, R-32) are presented. Comparisons are made to the behavior of CH4in the same burner and to published data on the lean limiting equivalence ratio, Φ0. The lean flammability limit of CH2F2in dry air is found to be Φ0= 0.78 ± 0.04. Concurrent computational modeling of the combustion of a one-dimensional, unstrained flame of CH2F2in air, individually and in mixtures with CH4, has been performed. Initial estimates of the laminar flame speed for CH2F2/air mixtures from stoichiometric to lean are reported and interpreted in light of the experimental results.