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The dynamics of a non-premixed rotating detonation engine from time-resolved temperature measurements
Proceedings of the Combustion Institute ( IF 3.4 ) Pub Date : 2020-10-18 , DOI: 10.1016/j.proci.2020.06.373
Christopher A. Fugger , Joseph G. Lopez , Keith D. Rein , Sukesh Roy , Andrew W. Caswell

The structure and dynamics of a hydrogen-air rotating detonation engine (RDE) are described based on 100-kHz laser absorption spectroscopy measurements of water temperature at four simultaneous locations within the detonation channel. The analysis focuses on the evolution of the flowfield over a 200 ms period for three separate air mass flow rate cases. Two-dimensional unwrapped visualizations of the temperatures show a flowfield structure containing regions with the detonation front, combustion products, oblique shock, and refilling reactants, qualitatively agreeing with previous simulations and experiments. A major conclusion is that water from the combustion products is measured throughout all space and time in the RDE, including near the injector, implying the presence of performance loss processes such as burning upstream of the detonation wave or the back recirculation of combustion products with fresh fuel–air. By analyzing the elevated temperatures of the reactants during the refill process, one estimation for the mass fraction of combustion products in the reactants is as high as 20–30% on average. This product mass fraction is found to be inversely proportional to the bulk air mass flow rate and decreases as time progresses. This indicates these non-ideal processes are more significant closer to RDE ignition for poorer performing operating conditions. For the largest air mass flow case, water temperatures near the nominally cold plenum conditions likely corroborate the presence of a recirculation region on the RDE inner body. Analysis of inter- and intra-cycle temperature dynamics further support non-ideal processes occurring behind the detonation wave and during the refill process. As a whole, the data indicates that the RDE performance is better as time progresses away from ignition or for higher air mass flow rates. These data are also important for comparison with numerical models.



中文翻译:

非预混旋转爆震发动机的动态特性,通过时间分辨温度测量得到

基于爆轰通道内四个同时位置的水温的100 kHz激光吸收光谱测量,描述了氢空气旋转爆轰发动机(RDE)的结构和动力学。分析着重于三种不同的空气质量流量情况在200毫秒内流场的演变。温度的二维展开图显示了流场结构,其中包含具有爆轰前沿,燃烧产物,倾斜冲击和重新填充反应物的区域,在质量上与以前的模拟和实验相符。一个主要结论是,在RDE的所有空间和时间(包括在喷油器附近)中,都测量了燃烧产物中的水。这意味着存在性能损失过程,例如在爆炸波上游燃烧或燃烧产物与新鲜燃料-空气的反向再循环。通过分析填充过程中反应物的高温,对反应物中燃烧产物的质量分数的一种估计平均高达20%到30%。发现该产品质量分数与总体空气质量流量成反比,并且随着时间的推移而降低。这表明在较差的运行条件下,这些不理想的过程更接近RDE点火。对于最大的空气质量流量情况,接近标称冷气室条件的水温可能证实了RDE内体上存在回流区域。周期间和周期内温度动力学的分析进一步支持了在爆轰波之后和在重新填充过程中发生的非理想过程。总体而言,数据表明,随着时间的增长,远离点火或空气质量流量较高时,RDE性能会更好。这些数据对于与数值模型进行比较也很重要。

更新日期:2020-10-18
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