The study examines chemiluminescence measurements and computations as a method of validation. Because chemiluminescent radicals are present in small concentrations and associated timescales are also small, a common assumption is that these are quasi-steady-state species and their transport can be ignored. This paper examines the above assumption using available data and simulation results, specifically aiming at a single element rocket combustor under strong pressure fluctuations. Variations in the kinetics rate constants are considered for assessing sensitivity of the results. Two additional aspects are explored: the ability of the excited species to represent the chemical heat release and the optical thickness of the medium. For the conditions of the study, the quasi-steady-state assumption in the case of OH* is found to be marginally insufficient while in the case of CH*, it is found to be acceptable. Modeled heat release is qualitatively better captured by CH* than OH* because of higher difference in the peak to asymptotic concentrations and lower ground state concentration.

中文翻译：

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在燃烧动力学中使用OH *和CH *作为放热标志

该研究将化学发光测量和计算作为一种验证方法。由于化学发光自由基的存在浓度很小，并且相关的时间尺度也很小，因此通常的假设是它们是准稳态物种，可以忽略它们的迁移。本文使用可用的数据和模拟结果检验了上述假设，特别是针对在强压力波动下的单元件火箭燃烧室。考虑动力学速率常数的变化以评估结果的敏感性。探讨了另外两个方面：激发物种表示化学放热的能力和介质的光学厚度。对于研究条件，在OH *的情况下，准稳态假设被认为是略微不足，而在CH *的情况下，则被认为是可接受的。从质量上讲，CH *比OH *能更好地模拟热量释放，因为峰到渐近浓度之间的差异更大，基态浓度更低。