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841.
842.
Yu. F. Gortyshov V. M. Gureev R. Sh. Misbakhov I. F. Gumerov A. P. Shaikin 《Russian Aeronautics (Iz VUZ)》2009,52(4):488-490
We present the results of experimental studies of the fuel hydrogen additive influence on the characteristics of a gas-piston
engine converted for operation by natural gas under changes of an ignition advance angle (IAA). The results of investigations
were used to determine the influence of the hydrogen additive on the effective engine efficiency and fuel consumption under
IAA changes. 相似文献
843.
We describe the results of determining the mass of the International Space Station using the data of MAMS accelerometer taken during correction of the station orbit on August 20, 2004. The correction was made by approach and attitude control engines (ACE) of the Progress transporting spacecraft. The engines were preliminary calibrated in an autonomous flight using the onboard device for measuring apparent velocity increment. The method of calibration is described and its results are presented. The error in station mass determination is about 1%. The same data of MAMS and similar data obtained during the orbit correction on August 26, 2004 were used for the analysis of high-frequency vibrations of the station mainframe caused by operation of the ACE of Progress. Natural frequencies of the ACE are determined. They lie in the frequency band 0.024–0.11 Hz. ACE operation is demonstrated to result in a substantial increase of microaccelerations onboard the station in the frequency range 0–1 Hz. The frequencies are indicated at which disturbances increase by more than an order of magnitude. The study described was carried out as a part of the Tensor technological experiment. 相似文献
844.
On the basis of generalization of the results of extensive trajectory calculations for trial charged particles moving in the geomagnetic field the method of calculation of effective vertical cutoff rigidity, taking into account the values of K p -index and local time, is developed. The IGRF and Tsyganenko-89 models are used for the geomagnetic field. A comparison of the results of model simulations with the experimental data on penetration of charged particles into near-Earth space is made, and penetration functions for typical spacecraft orbits are calculated. 相似文献
845.
E. L. Akim R. N. Arkhangelsky Yu. K. Zaiko S. M. Lavrenov A. L. Poroshin E. G. Ruzsky V. A. Stepaniants A. G. Tuchin D. A. Tuchin V. P. Fedotov V. S. Yaroshevsky 《Cosmic Research》2009,47(4):299-309
Basic concepts and algorithms laid as foundations of the scheme of landing on the Martian moon Phobos (developed for the Phobos-Grunt project) are presented. The conditions ensuring the landing are discussed. Algorithms of onboard navigation and control are described. The equations of spacecraft motion with respect to Phobos are considered, as well as their use for correction of the spacecraft motion. The algorithm of estimation of the spacecraft’s state vector using measurements with a laser altimeter and Doppler meter of velocity and distance is presented. A system for modeling the landing with a firmware complex including a prototype of the onboard computer is described. 相似文献
846.
The results of reconstruction of uncontrolled attitude motion of the Foton M-2 satellite using measurements with the accelerometer TAS-3 are presented. The attitude motion of this satellite has been previously
determined by the measurement data of the Earth’s magnetic field and the angular velocity. The TAS-3 data for this purpose
are used for the first time. These data contain a well-pronounced additional component which made impossible their direct
employment for the reconstruction of the attitude motion and whose origin was unknown several years ago. Later it has become
known that the additional component is caused by the influence of the Earth’s magnetic field. The disclosure of this fact
allowed us to take into account a necessary correction in processing of TAS-3 data and to use them for the reconstruction
of the attitude motion of Foton M-2. Here, a modified method of processing TAS-3 data is described, as well as results of its testing and employing. The testing
consisted in the direct comparison of the motion reconstructed by the new method with the motion constructed by the magnetic
measurements. The new method allowed us to find the actual motion of Foton M-2 in the period June 9, 2005–June 14, 2005, when no magnetic measurements were carried out. 相似文献
847.
We study the influence of additive and parametric slowly varying harmonic (at the Chandler frequency and doubled frequency) and stochastic Gaussian broadband perturbations on mathematical expectations, variances, and covariations of oscillations of the Earth’s pole. The influence of perturbations on both regular and irregular stochastic oscillations is considered in detail. Results of numerical experiments are presented. The developed models and software are included into information resources on the fundamental problem “Statistical dynamics of the Earth’s rotation” of Russian Academy of Sciences. 相似文献
848.
为研究超声速两相流混合机理,采用大涡模拟(LES)方法数值仿真了超声速混合层内液滴两相流流场结构.用二维盒式滤波法处理可压缩气相N-S方程,得到亚格子形式的LES控制方程;用轨道模型仿真液滴运动,并用单液滴蒸发模型模拟液滴蒸发过程.利用伪邻近法和互信息量法确定了相空间重构的嵌入维数和时间延迟,对混合层压力时间序列进行了相空间重构.分析了仿真结果中混合层的涡结构特性和液滴对流场的反作用效果,并讨论了混合层失稳过程的非线性特征.发现混合层发展的不同阶段与其系统的非线性特征值密切相关. 相似文献
849.
850.
两飞行器间无线数据链通信区域建模 总被引:3,自引:3,他引:0
为实现两飞行器在飞行过程中的正常通信,需建立一套通信区域的计算模型.基于空地无线数据链通信,从其实现正常通信的条件出发,考虑通信链路中的发射机、接收机、收发天线、传输空间及地球曲率、飞行器姿态角以及飞行器的空间位置关系等因素,分析研究了飞行器间无线数据链通信区域,建立了两飞行器间无线数据链通信区域的数学模型,包括天线、飞行高度、两飞行器空间位置关系、通信区域模型等.该模型已成功应用于某型号,为分析建立在无线数据链通信方式基础上的空地无线传输系统通信区域提供了参考,也适用于飞船、卫星等其它空空、空地无线数据通信系统. 相似文献