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Rocket

About: Rocket is a research topic. Over the lifetime, 14018 publications have been published within this topic receiving 95852 citations. The topic is also known as: rockets.


Papers
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Journal ArticleDOI
TL;DR: In this article, the waveforms and envelopes of resonance signals observed in the ionosphere at 2, 3, 4, and 5fH by rocket experiment are compared with the analytical results provided by a spatial ray-tracing procedure which takes the gradient of Earth's magnetic field into account.
Abstract: The waveforms and envelopes of resonance signals observed in the ionosphere at 2, 3, 4, and 5fH by rocket experiment are compared with the analytical results provided by a spatial ray-tracing procedure which takes the gradient of Earth's magnetic field into account. An approximate calculation yields the algebraic expression of the wave damping from whence the decrease of the received signals is deduced versus time as well as their frequency variations.

29 citations

Journal ArticleDOI
TL;DR: In this article, a simple model has been developed for predicting the velocity of "rocket" missiles generated by failure at the lower end of a vertical cylindrical pressure vessel containing gas and a cold liquid.
Abstract: A simple model has been developed for predicting the velocity of “rocket” missiles generated by failure at the lower end of a vertical cylindrical pressure vessel containing gas and a cold liquid. This model accurately predicts the velocities observed in a parallel experimental investigation. When modified to take account of liquid flashing to vapour during depressurization, the model has also been successfully applied to the case of “rockets” generated by failure of a vessel containing a hot liquid and a cover gas at a pressure sufficient to suppress boiling in normal operation. However, where “rockets” are generated by failure of a vessel containing a boiling liquid, the model significantly under predicts the “rocket” velocity in many cases. Here the enhanced experimental velocities are attributed to the increase in the apparent liquid volume, caused by the presence of the vapour bubbles, prolonging the liquid expulsion period. Simple correlations of the experimental data for all three cases have been developed using a parameter derived from the theoretical predictions. These define upper limit velocities for use in hazard assessment.

29 citations

Proceedings ArticleDOI
15 Jun 2002
TL;DR: In this article, the authors discuss a comprehensive test and analysis program that has been undertaken to develop a methodology to accurately predict the character and magnitude of this loading, which will be critical for the successful construction of the next generation of low cost, reliable rocket engines.
Abstract: During ground-tests of most production rocket engines over the last 30 years, large asymmetric transient side loads coming from the nozzle and related steady-state vibrational loads within the nozzle have been measured. The widely varying magnitude of these loads has been large enough to fail interfacing components as well as nozzles in these engines. This paper will discuss a comprehensive test and analysis program that has been undertaken to develop a methodology to accurately predict the character and magnitude of this loading. The project to-date has incorporated analytical modeling of both the fluid flow and the nozzle structure and testing of both full-scale and sub-scale rocket nodes. Examination of the test data indicates that one of the two-nodal diameter structural modes may be interacting with flow separation from the nozzle inside-wall in a self-excited or aeroelastic vibration phenomenon. If verified, this observation will be used to develop a methodology for design and analysis. A fuller understanding of the characteristics of this vibration will provide an increase in the accuracy and confidence of side load predictions, which will be critical for the successful construction of the next generation of low-cost, reliable rocket engines.

29 citations

Proceedings ArticleDOI
08 Jul 2007
TL;DR: In this paper, the transient combustion theory has been extended to hybrid rockets using liquid oxidizers with feed systems characterized by finite response times, and transfer functions for the feed coupled system with and with out flow isolation elements have been developed.
Abstract: In this paper, the transient combustion theory has been extended to hybrid rockets using liquid oxidizers with feed systems characterized by finite response times. Models for generic hybrid feed systems have been developed and these have been coupled to the combustion chamber dynamics with lag times introduced to model the delays associated with oxidizer vaporization and fuel gasification processes. This study has been limited to a simplified behavior for the combustion chamber that only includes the filling/emptying dynamics. The set of Ordinary Differential Equations that represent the system behavior have been linearized and nondimensionalized. Using the technique of Laplace Transformation, transfer functions for the feed coupled system with and with out flow isolation elements have been developed. The model has been used to investigate the stability behavior of the feed coupled system and to develop stability criteria in terms of the practical operational parameters for liquid fed hybrid motors. The oxidizer vaporization delay is treated as an input parameter which can be adjusted to match the observed oscillation frequency to the model prediction. As a practical application of the model, the estimated vaporization delay can be used to evaluate the atomization characteristics of injectors and pre-combustion chamber designs for hybrid rocket motors.

29 citations

01 Sep 1994
TL;DR: The solid core nuclear thermal rocket (NTR) represents the next major evolutionary step in propulsion technology with its attractive operating characteristics, which include high specific impulse (approximately 850-1000 s) and engine thrust to weight (approximately 4-20), the NTR can form the basis for an efficient lunar space transportation system (LTS) capable of supporting both piloted and cargo missions.
Abstract: The solid core nuclear thermal rocket (NTR) represents the next major evolutionary step in propulsion technology With its attractive operating characteristics, which include high specific impulse (approximately 850-1000 s) and engine thrust-to-weight (approximately 4-20), the NTR can form the basis for an efficient lunar space transportation system (LTS) capable of supporting both piloted and cargo missions Studies conducted at the NASA Lewis Research Center indicate that an NTR-based LTS could transport a fully-fueled, cargo-laden, lunar excursion vehicle to the Moon, and return it to low Earth orbit (LEO) after mission completion, for less initial mass in LEO than an aerobraked chemical system of the type studied by NASA during its '90-Day Study' The all-propulsive NTR-powered LTS would also be 'fully reusable' and would have a 'return payload' mass fraction of approximately 23 percent--twice that of the 'partially reusable' aerobraked chemical system Two NTR technology options are examined--one derived from the graphite-moderated reactor concept developed by NASA and the AEC under the Rover/NERVA (Nuclear Engine for Rocket Vehicle Application) programs, and a second concept, the Particle Bed Reactor (PBR) The paper also summarizes NASA's lunar outpost scenario, compares relative performance provided by different LTS concepts, and discusses important operational issues (eg, reusability, engine 'end-of life' disposal, etc) associated with using this important propulsion technology

29 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202211
2021373
2020480
2019624
2018537
2017493