排序方式: 共有266条查询结果,搜索用时 31 毫秒
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某发动机风扇进气畸变数值模拟 总被引:2,自引:3,他引:2
采用周向平均体积力的方法将叶片对气流的作用简化为体积力源项研究进气畸变对某航空发动机风扇的影响.分别对该风扇在均匀进气条件下和进口存在稳态总压畸变条件下的流场进行了模拟计算,得到了和雷诺平均Navier-Stockes(RANS)计算几乎完全一致的特性线以及流场主要结构特征,在进行进气畸变条件下流场模拟计算时成功地捕捉到了进口畸变扰动在流场中的传播情况,并能够正确反映进气畸变对压气机的影响.结果表明:压气机进气畸变流场有着大尺度、强耦合、信息传播三维性明显等特征,采用周向平均体积力研究方法可以利用非常少的计算资源加深对进气畸变流动的认识. 相似文献
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楔顶双孔探针测量跨声多级压气机转子出口三维动态流场的方法 总被引:2,自引:1,他引:2
发展了1种楔顶圆柱双孔高频压力探针测量三维动态流场的方法,并应用于某跨声速多级轴流压气机转子出口流场测量.该探针测量方法基于4孔针测量原理,通过旋转探针在3个角度测量的方法实现,并采用最小二乘拟合方法对探针气动校准数据进行处理,对拟合误差进行优化,得到最佳拟合阶次,进而获得精度较高的求解流场参数的近似函数.相比国内外同类探针,该楔顶圆柱双孔高频压力探针尺寸小、频响快、测量范围宽、测量精度高.借助高速锁相数据采集技术,利用该探针测量了某跨声速多级压气机转子出口三维动态流场,测量结果反映了该转子流动特征,提供了转子出口气流偏转角、俯仰角、总压、马赫数分布,并为优化压气机级间匹配指明了方向,为压气机流场诊断提供了一套行之有效的测量手段,验证了该高频压力探针测量技术的工程应用价值. 相似文献
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Curiosity’s Mars Hand Lens Imager (MAHLI) Investigation 总被引:1,自引:0,他引:1
Kenneth S. Edgett R. Aileen Yingst Michael A. Ravine Michael A. Caplinger Justin N. Maki F. Tony Ghaemi Jacob A. Schaffner James F. Bell III Laurence J. Edwards Kenneth E. Herkenhoff Ezat Heydari Linda C. Kah Mark T. Lemmon Michelle E. Minitti Timothy S. Olson Timothy J. Parker Scott K. Rowland Juergen Schieber Robert J. Sullivan Dawn Y. Sumner Peter C. Thomas Elsa H. Jensen John J. Simmonds Aaron J. Sengstacken Reg G. Willson Walter Goetz 《Space Science Reviews》2012,170(1-4):259-317
The Mars Science Laboratory (MSL) Mars Hand Lens Imager (MAHLI) investigation will use a 2-megapixel color camera with a focusable macro lens aboard the rover, Curiosity, to investigate the stratigraphy and grain-scale texture, structure, mineralogy, and morphology of geologic materials in northwestern Gale crater. Of particular interest is the stratigraphic record of a ~5?km thick layered rock sequence exposed on the slopes of Aeolis Mons (also known as Mount Sharp). The instrument consists of three parts, a?camera head mounted on the turret at the end of a robotic arm, an electronics and data storage assembly located inside the rover body, and a calibration target mounted on the robotic arm shoulder azimuth actuator housing. MAHLI can acquire in-focus images at working distances from ~2.1?cm to infinity. At the minimum working distance, image pixel scale is ~14?μm per pixel and very coarse silt grains can be resolved. At the working distance of the Mars Exploration Rover Microscopic Imager cameras aboard Spirit and Opportunity, MAHLI’s resolution is comparable at ~30?μm per pixel. Onboard capabilities include autofocus, auto-exposure, sub-framing, video imaging, Bayer pattern color interpolation, lossy and lossless compression, focus merging of up to 8 focus stack images, white light and longwave ultraviolet (365 nm) illumination of nearby subjects, and 8 gigabytes of non-volatile memory data storage. 相似文献
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支承松动的转子系统动力学模型及其故障诊断方法 总被引:6,自引:2,他引:6
针对滚动轴承转子系统支承松动故障 ,考虑了松动间隙的非线性情况 ,以转子动力学、Hertz接触理论和非线性动力学理论为基础 ,建立了转子系统的动力学模型。对转子系统动力学方程在松动故障和无故障情况下分别进行数值积分 ,得到两种情况下轴承座 (有故障时为松动端 )上的振动仿真信号。利用频谱和小波变换对所获振动信号进行了处理 ,并将结果进行了分析 ,得出小波变换不但能很好地诊断滚动轴承—转子系统的支承松动故障 ,而且比 Fourier变换在更低转速下诊断出转子系统的支承松动故障 相似文献
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