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191.
Proceeding from the first assumption of kinetic-molecular theory, the authors propose the Toms effect on reducing the hydrodynamic drag in a turbulent flow with polymer additives and its usage in power plants, to be explained. 相似文献
192.
The concept and definition of integrated flight performance for a small remotely piloted helicopter are introduced to obtain real operational values in performing a flight mission. 相似文献
193.
The paper regards two-impulse transfer from a low parking orbit into a circular orbit with the altitude less than 36 000 km, while the inclination correction is carried out with each maneuver. An approximate formula is proposed capable of evaluating analytically the optimal value of the first correction of inclination; the corresponding accuracy data are given. Examples are provided to show the operational efficiency of an optimal non-coplanar transfer of the type II with injections of satellites into various target orbits from Russian launch sites with due account of the available launch azimuths. 相似文献
194.
V. I. Tret’yakov I. G. Mitrofanov Yu. I. Bobronitskii A. V. Vostrukhin N. A. Gunko A. S. Kozyrev A. V. Krylov M. L. Litvak M. Lopez-Alegria V. I. Lyagushin A. A. Konovalov M. P. Korotkov P. V. Mazurov M. I. Mokrousov A. V. Malakhov I. O. Nuzhdin S. N. Ponomareva M. A. Pronin A. B. Sanin G. N. Timoshenko T. M. Tomilina M. V. Tyurin A. I. Tsygan V. N. Shvetsov 《Cosmic Research》2010,48(4):285-299
195.
M. K. Leont’ev A. V. Davydov S. A. Degtyarev I. L. Gladkii 《Russian Aeronautics (Iz VUZ)》2014,57(2):154-161
The results of simulating the dynamic characteristics of turbofan engines (TFE) during and after fan blade-out are presented. To solve the tasks, we constructed a nonlinear unsteady engine model that includes the low pressure rotor, high pressure rotor, cases, nacelle with reverse, engine hanger to the pylon, pylon itself, and aircraft hanger of the pylon to the wing. The rotor system model also includes the rolling bearings (stiffness of which is calculated for engine operation in different operating regimes), nonlinear hydrodynamic dampers, and elastic bushes (“squirrel cages”). 相似文献
196.
Thomas S. Richardson Cormac McFarlane Askin Isikveren Ken Badcock Andrea Da Ronch 《Progress in Aerospace Sciences》2011,47(8):647-659
One of the main drivers behind the SimSAC project and the CEASIOM software is to bring stability analysis and control system design earlier into the aircraft conceptual design process. Within this paper two very different aircraft are considered, a conventional T-tail based on the existing EA500 Very Light Jet and the second, a novel Z-wing configuration known as the GAV or general aviation vehicle. The first aircraft serves as a baseline comparison for the second, and the cruise case is considered as a benchmark for identifying potential drag reductions and aircraft stability characteristics. CEASIOM, the Computerised Environment for Aircraft Synthesis and Integrated Optimisation Methods, is used to generate aerodynamic data sets for both aircraft, create trim conditions and the associated linear models for classical stability analysis. The open-loop Z-wing configuration is shown to display both highly unstable and coupled modes before a multivariable Stability Augmentation System (SAS) is applied both to decouple and stabilise the aircraft. Within this paper, these two aircraft provide a test case with which to demonstrate the capabilities of the CEASIOM environment and the tools which have been developed during the SimSAC project. This new software suite is shown to allow conceptual development of unconventional novel configurations from mass properties through adaptive-fidelity aerodynamics to linear analysis and control system design. 相似文献
197.
L. V. Goryunov V. V. Takmovtsev D. V. Ignat’ev A. M. Erzikov 《Russian Aeronautics (Iz VUZ)》2012,55(4):379-382
In this paper, we present some experimental data on characteristics of plain journal bearings at different variants of oil supply inlet pipe arrangement and relative values of the shaft rotation speed and inlet pipe pressure. Also established is the significant growth of oil consumption when the inclination angle of the inlet throttling element axis is increased. 相似文献
198.
In this paper, we consider the main aspects of a problem in formation and control of a required microacceleration level as the most important characteristic of the space laboratory intended for realizing the gravitational and sensitive technological processes. The estimation model and methodology to control and estimate the microaccelerations are presented that are necessary for the well-founded choice of the spacecraft parameters and carrying out their flight and space tests, when the new special-purpose space laboratories are designed and constructed. 相似文献
199.
The analysis of structural features of the gas-distributing grid was carried out by modern facilities of computational gas
dynamics to equalize flow parameters upstream of a mixing head in LPRE with producer gas afterburning. For the given simulation
conditions we defined the optimal geometrical dimensions of the facets on the gas-distributing grid openings, providing the
maximal discharge coefficient and the minimal pressure differential. We also examined the grid design variants with the various
distribution of facets of different geometry, which allows the outflow parameters to be varied according to the grid area.
It is obtained, that a flat grid with various openings geometry in the sectors makes it possible to provide the best equalization
of the pressure and velocity fields upstream of the mixing head and the minimal pressure losses. 相似文献
200.
A mathematical model of complex vibrations for the cantilever Bernoulli-Euler beam in the XOZ plane constructed by the finite difference and finite element methods and the fourth-order Runge-Kutta method is presented.
We determined the critical value of the damping coefficient ɛ = 0.28, at which the system changes from the dissipative state
to conservative one, using the Morlet wavelet. The results of analyzing the frequency characteristics of the system are presented. 相似文献