Results 1 - 10 of 1588
Results 1 - 10 of 1588. Search took: 0.028 seconds
|Sort by: date | relevance|
[en] At the S. P. Korolev Rocket-Space Corporation (RSC) 'Energy' for long time pilot and research works on space Nuclear Energy Facilities (NEF) of electric capacity from 150 to 500 kW and MW range in nuclear electric-rocket engine facilities (NEREF) of its base have been carried out. Peculiarity of Nuclear Energy Facility is application of thermal emission reactor-converter (TRC) on fast neutrons, application of pure lithium-7 isotope in the capacity of coolant, and the high-temperature niobium alloy in the capacity of construction materials, module design of TRC and NEF at all. Principal attention is paid to basing of nuclear and radiation safety for production, launching, commissioning and decommissioning of these facilities. At present at the RSC 'Energy' the main volume of pilot work is emphasized on the module scheme NEF with TRC of electric capacity from 150 kW to 800-1000 kW for electric power plants creation for both inhabited Lunar base, and mine and processing complex for industrial Moon development. In the paper different possibilities for effective use of NEF and NEREF uniform technologies for further space development are given
[en] The lecture presents an overview of some recent results of the work carried out at Alta on the hydrodynamic design and rotordynamic fluid forces of cavitating turbopumps for liquid propellant feed systems of modern rocket engines. The reduced order models recently developed for preliminary geometric definition and noncavitating performance prediction of tapered-hub axial inducers and centrifugal turbopumps are illustrated. The experimental characterization of the rotordynamic forces acting on a whirling four-bladed, tapered-hub, variable-pitch high-head inducer, under different load and cavitation conditions is presented. Future perspectives of the work to be carried out at Alta in this area of research are briefly illustrated
[en] Derating is the operation of an item at a stress that is lower than its rated design value. Previous research has indicated that reliability can be increased from operational derating. In order to derate an item in field operation, however, an engineer must rate the design of the item at a stress level higher than the operational stress level, which increases the item's nominal failure rate and development costs. At present, there is no model available to quantify the cost and reliability that considers the design uprating as well as the operational derating. In this paper, we establish the reliability expression in terms of the derating level assuming that the nominal failure rate is constant with time for a fixed rated design value. The total development cost is expressed in terms of the rated design value and the number of tests necessary to demonstrate the reliability requirement. The properties of the optimal derating level are explained for maximizing the reliability or for minimizing the cost. As an example, the proposed model is applied to the design of liquid rocket engines. - Highlights: • Modeled the effect of derating design on the reliability and the development cost. • Discovered that derating design may reduce the cost of reliability demonstration test. • Optimized the derating design parameter for reliability maximization or cost minimization.
[en] Jet flow deflector is one of the most important facility in liquid rocket engine test stage. It is necessary to investigate the effect of rocket plume to the jet flow deflector. Based on the theory of computational fluid dynamics, the flow field of a rocket engine plume is simulated and analysed by numerical method. The velocity field and temperature field of the plume in rocket engine test are obtained. The structural characteristics of engine plume flow field and the impact effect on flow deflector are analysed. Finally, results are applied to the thermal protection design of the test stage. (paper)
[en] We analyse the two-dimensional motions of the rockets for various types of rocket thrusts, the air friction and the gravitation by using a suitable representation of the rocket equation and the numerical calculation. The slope shapes of the rocket trajectories are discussed for the three types of rocket engines. Unlike the projectile motions, the descending parts of the trajectories tend to be gentler and straighter slopes than the ascending parts for relatively large launching angles due to the non-vanishing thrusts. We discuss the ranges, the maximum altitudes and the engine performances of the rockets. It seems that the exponential fuel exhaustion can be the most potent engine for the longest and highest flights
[en] Aiming at the problem of task assignment of maintenance and repair for long-range rocket launchers, based on systematic review of the basic concepts and basic principles of Stackelberg game, Through the basic assumption’s analysis, the Stackelberg model is designed to allocate far-fire tasks. Finally, the results of running MATLAB are calculated. It shows that Stackelberg model of far-fire task allocation can effectively solve the problem of long-range rocket launcher maintenance and guarantee task assignment, which has strong practical significance. (paper)
[en] To decrease the metal content in the housings of solid-fuel rocket engines, the metallic joint reinforcement may be replaced by plastic components. A device for the production of reinforcement blanks by winding is developed. This system ensures polymerization and machining of the plastic.
[en] A new impetus to manned Mars exploration was introduced by President Bush in his Space Exploration Initiative. This has led, in turn, to a renewed interest in high-thrust nuclear thermal rocket propulsion (NTP). The purpose of this report is to give a brief tutorial introduction to NTP and provide a basic understanding of some of the technical issues in the realization of an operational NTP engine. Fundamental physical principles are outlined from which a variety of qualitative advantages of NTP over chemical propulsion systems derive, and quantitative performance comparisons are presented for illustrative Mars missions. Key technologies are described for a representative solid-core heat-exchanger class of engine, based on the extensive development work in the Rover and NERVA nuclear rocket programs (1955 to 1973). The most driving technology, fuel development, is discussed in some detail for these systems. Essential highlights are presented for the 19 full-scale reactor and engine tests performed in these programs. On the basis of these tests, the practicality of graphite-based nuclear rocket engines was established. Finally, several higher-performance advanced concepts are discussed. These have received considerable attention, but have not, as yet, developed enough credibility to receive large-scale development
[en] Nuclear power has been considered for space applications since the 1960s. Between 1955 and 1972 the US built and tested over twenty nuclear reactors/ rocket-engines in the Rover/NERVA programs. However, changes in environmental laws may make the redevelopment of the nuclear rocket more difficult. Recent advances in fuel fabrication and testing options indicate that a nuclear rocket with a fuel form significantly different from NERVA may be needed to ensure public support. The Center for Space Nuclear Research (CSNR) is pursuing development of tungsten based fuels for use in a NTR, for a surface power reactor, and to encapsulate radioisotope power sources. The CSNR Summer Fellows program has investigated the feasibility of several missions enabled by the NTR. The potential mission benefits of a nuclear rocket, historical achievements of the previous programs, and recent investigations into alternatives in design and materials for future systems will be discussed.