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51.
异型孔空心叶片壁厚检测的试验研究 总被引:2,自引:0,他引:2
发动机叶片的结构型式和制造误差,直接影响发动机的性能和使用寿命。运用超声波法和电涡流法,对两种不同材料和形式的试件进行了试验。电涡流法受到探头直径和试件几何尺寸的影响,测量误差大,超声波法由于存在测量盲区,测量厚度的下限受到限制。但测量值与实际值相关,若对探头加以改进,用于异型孔空心叶片壁厚检测是可行的。 相似文献
52.
分析了模拟得到的可以传播到1AU以远的日地空间磁流体力学激波与Rankine-Hugnoniot跃变关系的符合程度.通过对模拟激波的结构及其在传播过程中的演化进行的分析,提出了模拟激波的定位方法;基于所提出的定位方法,利用向长青提出的确定MHD激波局地参数的方法计算了模拟得到的激波与Rankine-Hugnoniot跃变关系的偏差.结果表明在激波传播到100Rs以后,激波对中前向快激波与Rankine-Hugnoniot关系的符合达到很高的程度,相对误差在10^-2数量级以内;并且在激波传播到150 Rs以后,相对误差在10^-3数量级以内.这个结果说明文中所使用的有限差分数值格式能较好地模拟激波. 相似文献
53.
S.V. Chalov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2005,35(12):2106-2114
It may not be doubted anymore that anomalous cosmic rays (ACRs) are produced in the heliosphere from interplanetary pick-up ions through their acceleration at the solar wind termination shock. However, there is no general agreement in the community of heliospheric researchers concerning the mechanism of injection of the pick-up ions into the shock acceleration. We discuss here three possible ways for pick-up ions to be involved into the acceleration process at the termination shock: (1) preacceleration of pick-up ions in the whole region from the Sun up to the termination shock by solar wind turbulences and interplanetary shock waves, (2) local preacceleration of pick-up ions in a vicinity of the termination shock by shock surfing, and (3) formation of high-velocity tails in pick-up ion spectra consisting of secondary pick-up ions which are produced in the supersonic solar wind due to ionization of energetic neutral atoms entering from the inner heliosheath. 相似文献
54.
<正> 飞机结构所承受的噪声载荷声压级超过130dB时,经较长时间激励,往往在噪声诱导应力较大的区域里产生疲劳破坏。而在各种类型的结构件中声疲劳破坏的相对发生率以蒙皮壁板结构为最高。 本文采用矩形铝合金平板来模拟蒙皮壁板结构,对其进行了声疲劳寿命计算与试验研究. 相似文献
55.
Matthew G. Baring 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
It is widely accepted that the prompt transient signal in the 10 keV–10 GeV band from gamma-ray bursts (GRBs) arises from multiple shocks internal to the ultra-relativistic expansion. The detailed understanding of the dissipation and accompanying acceleration at these shocks is a currently topical subject. This paper explores the relationship between GRB prompt emission spectra and the electron (or ion) acceleration properties at the relativistic shocks that pertain to GRB models. The focus is on the array of possible high-energy power-law indices in accelerated populations, highlighting how spectra above 1 MeV can probe the field obliquity in GRB internal shocks, and the character of hydromagnetic turbulence in their environs. It is emphasized that diffusive shock acceleration theory generates no canonical spectrum at relativistic MHD discontinuities. This diversity is commensurate with the significant range of spectral indices discerned in prompt burst emission. Such system diagnostics are now being enhanced by the broad-band spectral coverage of bursts by the Fermi Gamma-Ray Space Telescope; while the Gamma-Ray Burst Monitor (GBM) provides key diagnostics on the lower energy portions of the particle population, the focus here is on constraints in the non-thermal, power-law regime of the particle distribution that are provided by the Large Area Telescope (LAT). 相似文献
56.
《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2020,65(11):2507-2514
The effect of the rocket exhaust products on the D-region of the ionosphere is investigated with the help of Very low frequency (VLF) electromagnetic wave propagation characteristics within the Earth-ionosphere waveguide. The changes in the electron density profile are computed from the observed VLF signal amplitude perturbations about 3 dB during the rocket launch. We find a localized electron depletion in the lower ionosphere at an altitude of around 58 km, that is thought to be originated by the attachment of ionospheric ion and molecular hydrogen along with water molecule in the exhaust product of first stage burn of Geosynchronous Launch Vehicle (GSLV) rocket at the time of GSLV launched from Sriharikota, India, on 27 August 2015 at 11:22 UT (16:52 IST). The ionospheric depletion perturbed the navigational VLF signal (VTX = 17 kHz) 134 s after the launch of the GSLV rocket. 相似文献
57.
国家数值风洞高超声速流动模拟软件HyFLOW的研制对打破国外同类软件的技术壁垒具有重要意义。与国外DPLR软件进行了对比研究,同时系统介绍了HyFLOW软件求解器的数值方法、物理化学模型以及壁面催化特性计算模型等主要方法,采用典型算例对有限催化模型进行了数值验证,最后基于LENS风洞试验146 mm返回器标模外形开展了高超声速气动热特性数值模拟。研究结果表明,HyFLOW软件在高超声速热化学非平衡流动模拟与评估方面的气动力计算精度高,与国外同类软件DPLR相当,同时其壁面催化条件下的气动热计算精度可靠,可信度高。 相似文献
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Effect of blade tip winglet on the performance of a highly loaded transonic compressor rotor 总被引:2,自引:1,他引:1
《中国航空学报》2016,(3):653-661
The tip leakage flow has an important influence on the performance of transonic com-pressor. Blade tip winglet has been proved to be an effective method to control the tip leakage flow in compressor, while the physical mechanisms of blade tip winglet have been poorly understood. A numerical study for a highly loaded transonic compressor rotor has been conducted to understand the effect of varying the location of blade tip winglet on the performance of the rotor. Two kinds of tip winglet were designed and investigated. The effects of blade tip winglet on the compressor over-all performance, stability and tip flow structure were presented and discussed. It is found that the interaction of the tip winglet with the flow in the tip region is different when the winglet is located at suction-side or pressure-side of the blade tip. Results indicate that the suction-side winglet (SW) is ineffective to improve the performance of compressor rotor. In addition, a significant stall range extension equivalent to 33.74% with a very small penalty in efficiency can be obtained by the pressure-side winglet (PW). An attempt has been made to explain the fundamental mechanisms of blade tip winglet in detail. 相似文献