Dual-Mode Scramjet Combustor: Numerical Sensitivity and Evaluation of Experiments
Dual-Mode Scramjet Combustor: Numerical Sensitivity and Evaluation of Experiments
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DOI：
10.2514/6.2012-947
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发表时间：
2012-01
期刊：
影响因子：
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通讯作者：
Ryan T. Milligan;Jiwen Liu;Chung-Jen Tam;D. Eklund;M. Hagenmaier;D. Davis;D. Risha;M. Gruber;T. Mathur
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文献类型：
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作者：
Ryan T. Milligan;Jiwen Liu;Chung-Jen Tam;D. Eklund;M. Hagenmaier;D. Davis;D. Risha;M. Gruber;T. Mathur
翻译后摘要：在空军研究实验室的推进局（AFRL/RZ）在研究细胞22（RC 22）进行实验。对实验中的12种情况进行了计算分析，每种情况在发动机工作条件和/或燃烧室构型方面都有所不同。对所有12种情况进行了初步计算，以建立基线计算方法。对其中一种情况进行了计算，以测试对湍流施密特数、反应速率和网格分辨率的敏感性。使用敏感性分析结果对基线分析的改进扩展到另外两个病例。结果表明，调整施密特数，反应速率，或网格细化改善了与实验数据的一致性为两种情况下，相对于基线结果，但恶化的第三种情况下的协议。与施密特数和/或反应速率的校准相比，网格细化是改善基线分析的更好方法，这一点尚未确定。在一种情况下，使用化学反应区域中的局部细化对网格进行改进产生了更好的结果，并且在计算上比全局细化网格更便宜。使用Y+值高达38的壁函数获得的结果或使用Y+值约为1的壁积分获得的结果之间的差异可忽略不计。通过使用恒定CFL或恒定时间步长对结果进行平均获得的周期性结果之间的差异可忽略不计。使用恒定CFL方法对结果进行CFL平均的计算成本比使用恒定时间步长方法低5.4倍。计算表明，2.53-lbm/sec。在RC 22的试验装置中，在燃烧室的出口处，空气泄漏到涡轮增压器壳体中。
Abstract : Experiments were performed at the Air Force Research Laboratory's Propulsion Directorate (AFRL/RZ) in Research Cell 22 (RC22). Twelve cases from the experiment were computationally analyzed and each case varied in either engine operating condition and/or combustor configuration. Initial computations were performed on all twelve cases to establish a baseline computational approach. Computations were performed on one of the cases to test sensitivity to turbulent Schmidt number, reaction rate, and grid resolution. Improvements to the baseline analysis using the results from the sensitivity analyses were extended to two additional cases. It was shown that adjustments in Schmidt number, reaction rate, or grid refinement improved the agreement with experimental data for two cases relative to the baseline results, but worsened agreement for the third case. It was left undetermined that grid refinement was a better approach to improving the baseline analysis as compared to calibrations in Schmidt number and/or reaction rate. Improvement to the grid using local refinement in regions with chemical reactions produced better results for one case and was computationally less expensive than globally refining the grid. Negligible differences were shown between results that were obtained using wall functions with Y+ value as high as 38 or results obtained using wall integration with Y+ values around one. Negligible differences were shown between periodic results that were obtained by averaging results using either a constant CFL or a constant time step. CFL-averaging a result using the constant CFL approach was 5.4 times less computationally expensive than using the constant time step approach. Computations showed that 2.53-lbm/sec. of air leaked into the exhauster housing at the exit of the combustor in RC22's test apparatus.