The linear high frequency stability of DLR’s cryogenic H2/O2 BKD test chamber is assessed using a hybrid computational fluid dynamic/computational aeroacoustic methodology, which is based on single flame simulations for the generation of an adequate mean flow and for the calibration of feedback models as well as on frequency space transformed linearized Euler equations. The application of a realistic mean flow field including combustion explains the spatial separation of transverse modes into a near face plate mode, which is found linearly unstable under certain operation conditions for the first transverse and a rear part mode. The axial mode shape length as well as eigenfrequencies is affected by propellant injection specifications and, in consequence, decisively influence pressure and transverse velocity sensitive dynamic flame response. The stability assessment procedure is finally applied to four operation conditions and the linear stability is predicted for the first transverse mode.

中文翻译：

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低温火箭发动机的线性稳定性评估

使用混合计算流体动力/计算气动声学方法评估DLR低温H2 / O2 BKD试验箱的线性高频稳定性，该方法基于单个火焰模拟以产生足够的平均流量并按如下方式校准反馈模型：以及在频率空间上变换的线性化Euler方程。实际的平均流场（包括燃烧）的应用解释了横向模式在空间上的分离成近面板模式，在第一横向模式和后部模式的某些操作条件下，线性模式不稳定。轴向模式形状的长度以及本征频率受推进剂喷射规格的影响，因此，决定性地影响压力和横向速度敏感的动态火焰响应。