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首页> 外文会议>AHS Specialists Conference on Aeromechanics Design for Transformative Vertical Flight >Generation of Mars Helicopter Rotor Model for Comprehensive Analyses
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Generation of Mars Helicopter Rotor Model for Comprehensive Analyses

机译：综合分析的MARS直升机转子模型

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The present research is aimed at providing a performance model for the Mars Helicopter (MH), to understand the complexity of the flow, and identify future regions of flow simulation improvement. The low density of the Martian atmosphere and the relatively small MH rotor, result in very low chord-based Reynolds number flows (Re_c ≈ 10~3 to Re_c ≈ 10~4). The low density and low Reynolds numbers reduce the lifting force and lifting efficiency, respectively. The high drag coefficients in subcritical flow, especially for thicker sections, are attributed to laminar separation from the rear of the airfoil. In the absence of test data, efforts have been made to explore these effects using prior very low Reynolds number research efforts. The rotor chord-based Reynolds number range is observed to be subcritical, which makes boundary layer transition unlikely to occur. The state of the two-dimensional rotor boundary layer in hover is approximated by calculating the instability point, laminar separation point, and the transition location to provide understanding of the flow state in the high Mach-low Reynolds number regime. The results are then used to investigate the need for turbulence modeling in Computational Fluid Dynamics (CFD) calculations. The goal is to generate a performance model for the MH rotor for a free wake analysis because of the low cost for design. In this study, a Reynolds-Averaged Navier-Stokes (RANS) based approach is used to generate the airfoil deck using C81Gen with experimental data for very high angles of attack. A full Grid Resolution Study is performed and over 4,500 cases are completed to create the full airfoil deck. The laminar separation locations are predicted within the accuracy of the approximate method when compared with the CFD calculations. The model is presented through airfoil data tables (c81 files) that are used by comprehensive rotor analysis codes such as CAMRADII or the mid-fidelity CFD solver RotCFD. Finally, the rotor performance is compared with experimental data from the 25ft Space Simulator at the NASA Jet Propulsion Laboratory (JPL) and shows good correlation for the rotor Figure of Merit over the available thrust range.
机译：目前的研究旨在为火星直升机（MH）提供性能模型，以了解流程的复杂性，并确定未来的流动模拟改进区域。火星气氛的低密度和相对小的MH转子，导致非常低的弦雷诺数流量（RE_C≈10〜3至re_c≈10〜4）。低密度和低雷诺数分别降低了提升力和提升效率。亚临界流动的高拖曳系数，特别是对于较厚的部分，归因于翼型的后部的层状分离。在没有测试数据的情况下，已经使用现有的非常低的雷诺数研究工作来探索这些效果。观察到基于转子弦的雷诺数范围是亚临界的，这使得不太可能发生边界层过渡。通过计算不稳定点，层状分离点和过渡位置来近似悬停中的二维转子边界层的状态，以提供高马赫低雷诺数方案中的流动状态的理解。然后使用结果来研究计算流体动力学（CFD）计算中湍流建模的需求。目标是为MH转子产生性能模型，因为设计成本低，因此为自由唤醒分析。在这项研究中，基于雷诺平均的Navier-Stokes（RANS）的方法用于使用C81GEN产生翼型甲板，其实验数据对于非常高的攻击角度。进行完整的网格分辨率研究，完成4,500例，以创建完整的翼型甲板。与CFD计算相比，在近似方法的准确性内预测层间分离位置。该模型通过翼型数据表（C81文件）提出，这些数据表（C81文件）由Camradii或Mid-PideLity CFD Solver Rotcfd等综合转子分析代码使用。最后，将转子性能与来自美国航空航天局喷射推进实验室（JPL）的25FT空间模拟器的实验数据进行比较，并且对可用推力范围的旋转仪器的转子形式显示出良好的相关性。

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