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371.
A new approach to the design-systematic provision of autorotation landing safety for a helicopter with skid type landing gear is proposed. We analyzed the existing simulation techniques and experimental studies regarding this problem. The main existing problems both in design simulation and the system of systematic requirements to the conditions of rating the loads on the skid landing gear are identified. Also proposed are the most optimal solutions to overcome the existing systematic contradictions and increase safety of helicopter piloting at autorotation landing. 相似文献
372.
航空发动机转速摆动问题研究 总被引:1,自引:0,他引:1
针对某型航空发动机闭环转速控制器引起的转速摆动问题进行研究,分析得出转速控制器是一个典型的比例积分控制器,并建立了转速控制器的AMESim模型。通过模型得到转速控制器的频率特性,发现其截止频率与转速摆动频率重合。分析指出转速摆动量与比例控制器精度的关系,找到了转速摆动的根本原因,并通过设计稳态试验台实现了验证,指出了解决转速摆动和提高控制精度的方法。 相似文献
373.
374.
M. I. Panasyuk S. I. Svertilov V. V. Bogomolov G. K. Garipov V. O. Barinova A. V. Bogomolov N. N. Veden’kin I. A. Golovanov A. F. Iyudin V. V. Kalegaev P. A. Klimov A. S. Kovtyukh E. A. Kuznetsova V. S. Morozenko O. V. Morozov I. N. Myagkova V. L. Petrov A. V. Prokhorov G. V. Rozhkov E. A. Sigaeva B. A. Khrenov I. V. Yashin S. I. Klimov D. I. Vavilov V. A. Grushin T. V. Grechko V. V. Khartov V. A. Kudryashov S. V. Bortnikov P. V. Mzhel’skiy A. P. Papkov S. V. Krasnopeev V. V. Krug V. E. Korepanov S. Belyaev A. Demidov Ch. Ferenz L. Bodnar P. Szegedi H. Rotkel M. Moravskiy Il Park Jin-A Jeon Ji-In Kim Jik Lee 《Cosmic Research》2016,54(4):261-269
The program of physical studies on the Vernov satellite launched on July 8, 2014 into a polar (640 × 830 km) solar-synchronous orbit with an inclination of 98.4° is presented. We described the complex of scientific equipment on this satellite in detail, including multidirectional gamma-ray detectors, electron spectrometers, red and ultra-violet detectors, and wave probes. The experiment on the Vernov satellite is mainly aimed at a comprehensive study of the processes of generation of transient phenomena in the optical and gamma-ray ranges in the Earth’s atmosphere (such as high-altitude breakdown on runaway relativistic electrons), the study of the action on the atmosphere of electrons precipitated from the radiation belts, and low- and high-frequency electromagnetic waves of both space and atmospheric origin. 相似文献
375.
376.
在多段翼型风洞实验中,很难观察翼型不同迎角下主翼、襟翼上的绕流及缝道流动。使用了O-H型混合的结构化网格,采用k-ε二方程湍流模型求解可压的N—S方程来模拟二元风洞中两段翼型的流场。计算结果与实验进行了比较,结果表明:计算与实验结果吻合良好,说明本方法可以较好地模拟两段翼型的绕流,并能很好地显示流场的变化情况。另外,从结果中可以看出:随着迎角的变化,主翼尾流和缝道间的流动对襟翼附面层分离有很大的影响作用。 相似文献
377.
尾缝是涡轮叶片中的重要冷却结构.为解决复合弯扭叶片尾缝的精确建模问题并提高其建模效率,提出了包含尾缝工具体创建和尾缝窗口创建过程的创成式尾缝快速建模方法.首先通过叶身内外型截面线自动匹配算法、叶盆叶背曲线方位判断算法,创建具有和叶身相同或相近弯扭状况的尾缝工具体.之后借助自定义的数据结构记录各组尾缝窗口信息,创建多组不同规格的尾缝窗口,完成尾缝建模.最后使用UG Open API工具开发了尾缝快速建模程序,并通过实例验证了所提出方法的可行性. 相似文献
378.
M. V. Zakhvatkin Yu. N. Ponomarev V. A. Stepan’yants A. G. Tuchin G. S. Zaslavskiy 《Cosmic Research》2014,52(5):342-352
A developed method of determination of orbital parameters allows one to estimate, along with orbit elements, some additional parameters that characterize solar radiation pressure and perturbing accelerations due to unloadings of reactiion wheels. A parameterized model of perturbing action of solar radiation pressure on the spacecraft motion is described (this model takes into account the shape, reflecting properties of surfaces, and spacecraft attitude). Some orbit determination results are presented obtained by the joint processing of radio measurements of slant range and Doppler, laser range measurements used to calibrate the radio measurements, optical observations of right ascension and declination, and telemetry data on spacecraft thrusters’ firings during an unloading of reaction wheels. 相似文献
379.
战备完好性是影响舰空导弹作战效能的重要保障性综合参数。在分析了舰空导弹舰上使用剖面一般形式的基础上,给出了舰空导弹舰上使用阶段战备完好性的定义,建立了无定检和有定检 2种情况下的战备完好性评估模型,并分析了值班可靠度、定检时间、舰上贮存备用导弹数量等因素对战备完好性的影响关系。文章可为舰空导弹舰上使用保障决策提供重要的理论依据。 相似文献
380.
P. R. Christensen V. E. Hamilton G. L. Mehall D. Pelham W. O’Donnell S. Anwar H. Bowles S. Chase J. Fahlgren Z. Farkas T. Fisher O. James I. Kubik I. Lazbin M. Miner M. Rassas L. Schulze K. Shamordola T. Tourville G. West R. Woodward D. Lauretta 《Space Science Reviews》2018,214(5):87
The OSIRIS-REx Thermal Emission Spectrometer (OTES) will provide remote measurements of mineralogy and thermophysical properties of Bennu to map its surface, help select the OSIRIS-REx sampling site, and investigate the Yarkovsky effect. OTES is a Fourier Transform spectrometer covering the spectral range 5.71–100 μm (\(1750\mbox{--}100~\mbox{cm}^{-1}\)) with a spectral sample interval of \(8.66~\mbox{cm}^{-1}\) and a 6.5-mrad field of view. The OTES telescope is a 15.2-cm diameter Cassegrain telescope that feeds a flat-plate Michelson moving mirror mounted on a linear voice-coil motor assembly. A single uncooled deuterated l-alanine doped triglycine sulfate (DLATGS) pyroelectric detector is used to sample the interferogram every two seconds. Redundant ~0.855 μm laser diodes are used in a metrology interferometer to provide precise moving mirror control and IR sampling at 772 Hz. The beamsplitter is a 38-mm diameter, 1-mm thick chemical vapor deposited diamond with an antireflection microstructure to minimize surface reflection. An internal calibration cone blackbody target provides radiometric calibration. The radiometric precision in a single spectrum is \(\leq2.2 \times 10^{-8}~\mbox{W}\,\mbox{cm}^{-2}\,\mbox{sr} ^{-1}/\mbox{cm}^{-1}\) between 300 and \(1350~\mbox{cm}^{-1}\). The absolute integrated radiance error is \(<1\%\) for scene temperatures ranging from 150 to 380 K. The overall OTES envelope size is \(37.5 \times 28.9 \times 52.2~\mbox{cm}\), and the mass is 6.27 kg. The power consumption is 10.8 W average. OTES was developed by Arizona State University with Moog Broad Reach developing the electronics. OTES was integrated, tested, and radiometrically calibrated on the Arizona State University campus in Tempe, AZ. 相似文献