Experimental and numerical investigation of thermo-acoustic instability in a liquid-fuel aero-engine combustor at elevated pressure: Validity of large-eddy simulation of spray combustion
Experimental and numerical investigation of thermo-acoustic instability in a liquid-fuel aero-engine combustor at elevated pressure: Validity of large-eddy simulation of spray combustion
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DOI：
10.1016/j.combustflame.2015.03.014
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发表时间：
2015-06-01
影响因子：
4.4
通讯作者：
Kurose, Ryoichi
中科院分区：
文献类型：
--
作者：
Tachibana, Shigeru;Saito, Kinya;Kurose, Ryoichi
利用光学测量得到的实验数据，对喷雾燃烧大涡模拟(LES)应用于实际航空发动机燃烧室热声不稳定性机理研究的可行性进行了研究。在日本宇宙航空研究开发机构的高温高压燃烧试验设施中，使用分级燃料喷射器进行了单扇区燃烧试验。动态压强的测量选择了峰值频率约为500 Hz、幅度大于40kPa的自激热声不稳定性较强的不稳定操作条件，并对其进行了OH-PLIF和OH中心点化学发光研究。在相同的条件下进行了大涡模拟计算，并考虑了动压和非定常火焰行为，通过与实验数据的比较，验证了大涡模拟的应用。此外，还利用大涡模拟数据进行了较为详细的研究，重点考察了速度、蒸发速率、当量比和放热率等非定常特性。总的来说，大涡模拟成功地再现了热声不稳定性过程中实验观察到的压力和火焰结构的非定常特征，尽管大涡模拟与实验结果在振荡幅度和局部火焰行为方面存在一些差异，例如周期性的火焰回火。在大涡模拟数据中，火焰表面积乘积和火焰面平均当量比随时间的演化与总放热率的变化规律一致，表明热声不稳定性是一种简单的主导机制。这些结果为进一步研究燃料的空间分布及其时间变化等关键物理参数对燃烧不稳定性的影响提供了证据。(C)2015年，燃烧研究所。爱思唯尔公司出版，版权所有。
The feasibility of applying the large-eddy simulation (LES) of spray combustion to the investigation of the thermo-acoustic instability mechanisms in practical aero-engine combustors was examined, employing experimental data obtained from optical measurements. Single sector combustion tests using a staged fuel injector were conducted at the JAXA high temperature and pressure combustion test facility. An unstable operating condition exhibiting strong self-excited thermo-acoustic instability with a peak frequency of approximately 500 Hz and an amplitude more than 40 kPa was chosen for measurements of the dynamic pressure, in addition to OH-PLIF and OH center dot chemiluminescence studies. LES calculations were performed under the same conditions and the use of LES was validated based on comparisons of results with experimental data, considering the dynamic pressure and unsteady flame behaviors. In addition, a more detailed investigation was performed with the LES data, focused on unsteady characteristics such as velocity, evaporation rate, equivalence ratio and heat release rates. In general, LES was found to successfully reproduce the experimentally observed unsteady characteristics of pressure and flame structures during thermo-acoustic instability, though there were several discrepancies between LES and experimental results with regard to the oscillation amplitude and local flame behavior, such as the periodical flame flashback. In the LES data, the time evolution of the product of the flame surface area and the flame-area-averaged equivalence ratio were in good agreement with the overall heat release rate variations, suggesting a simple dominant mechanism for the thermo-acoustic instability. These results provide evidence for the feasibility of employing LES as a means of further exploring the effects of key physical parameters, such as the spatial distribution of fuel and its temporal variations, on combustion instability. (C) 2015 The Combustion Institute. Published by Elsevier Inc. All rights reserved.