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.

Heavy ion beam-ionosphere interactions - Electron acceleration

Abstract: Moore et al. (1982) described a number of unexpected effects which were observed during the first Argon Release Controlled Study (ARCS 1, or rocket flight 29:014). The present paper provides a description of detailed analyses of the interaction of the argon beam with the ionosphere. An important feature of the considered test was that all detectors and the Ar(+) gun remained attached to the rocket throughout the flight. It is pointed out that the most dramatic effect of ion gun operation on ARCS 1 involved large changes in the fluxes of electrons with energies below about 600 eV. The observations are discussed, taking into account the distribution functions, azimuth dependence, and electron and ion trajectories. Attention is given to the perpendicular ion beam, the parallel ion beam, the acceleration of downgoing and upgoing electrons, and aspects of wave generation.

Rocket propulsion by thermonuclear micro-bombs ignited with intense relativistic electron beams.

Abstract: Discussion of a method for the ignition of a thermonuclear microbomb by means of an intense relativistic electron beam with regard to its potential application to rocket propulsion. With such a system, exhaust velocities up to 1000 km/sec, corresponding to a specific impulse of 100,000 sec, seem to be within the realm of possibility. The rocket is propelled by a chain of thermonuclear microbombs exploded in a concave magnetic mirror produced by superconducting field coils. The magnetic pressure of the field reflects the fireball generated by the explosion. For the large capacitor bank required to generate the intense relativistic electron beam, a desirable lightweight design may be possible through use of ferroelectric materials. Because of the high cost of the T-D and He 3-D thermonuclear material, the system has to be optimized by minimizing the T-D and He 3-D consumption by a proper TD and He 3-D fuel to hydrogen propellant mass ratio, leading to a larger total system mass than would be absolutely necessary.

Investigations of the T-burner and its role in combustion instability studies

Abstract: Of several devices introduced to study combustion instability in solid rocket propellants, one, known as the "T-burner," has become the most widely used. With this device the response of a burning propellant to a small pressure disturbance can be measured. Such information is vital both to the understanding of unsteady combustion processes as well as to the assessment of the stability characteristics of solid rocket motors. Although the T-burner has been used for several years, several questions concerning the device have arisen and, for the most part, have remained unanswered. Moreover, little effort has been given toward showing the relevance of T-burner data to predictions of instability in rocket motors. The present investigations, comprising over 400 test firings in T-burners of various lengths and diameters, were undertaken with the major objective of gaining a better understanding of the T-burner itself in order to answer some of these unresolved questions. Another objective was to compare T-burner predictions of rocket motor instability with actual observations made in a previous study. Among the investigations was a comparison of several ignition procedures which showed clearly that a poor, uneven ignition can seriously affect the test results. Included among the ignition studies were tests conducted in transparent chambers to permit high-speed motion photography of the firings. These tests confirmed the common assumption that the T-burner is basically a one-dimensional device. Tests using burners of different diameters showed that although the acoustic losses of the T-burner are nearly independent of diameter, the limiting amplitude of the oscillations is strongly dependent on the latter. The dilemma raised by these observations was resolved by measurements which indicate that the heat transfer from the combustion gases to the burner wall is strongly dependent on the amplitude of the waves. From these measurements emerged a nonlinear description of the damping in the T-burner which accounts for both the behavior of the losses as well as that of the limiting amplitude. When two independent T-burner methods were compared, the results obtained were initially in very poor agreement. However, when the T-burner losses were assumed to be non-linear as mentioned earlier, excellent agreement was observed. Finally, the T-burner predictions of instability in rocket motors were in rather poor agreement with direct observations made in a previous study. Although this lack of agreement is not understood, it is doubtful in the light of the present investigations that the major error lies in the T-burner measurements, for these should be relatively accurate. Moreover, these results indicate the need for more comparisons of this type in order to determine the usefulness of the T-burner in predicting combustion instability in solid propellant rockets.

Computational Fluid Dynamics Simulation of Hybrid Rockets of Different Scales

Abstract: CFX software is used to simulate different hybrid rocket configurations, applying liquid N2O as the oxidizer and paraffin as the fuel. This work is the prosecution of a previous paper analyzing liquid injection in a lab-scale hybrid rocket. It is focused on the formulation of the most suitable simulation technique to represent another type of liquid injector, compared with the one described in the previous paper. It also aims at extending the computational fluid dynamics simulation approach to hybrid rockets of larger scales. To validate computational fluid dynamics output, experimental results coming from both a laboratory scale and an increased-scale engine have been used. The different geometries studied include an increased-scale engine with a cylindrical grain having no diaphragm, the same rocket with a one-hole diaphragm inside the fuel grain, and a lab-scale rocket with a one-hole diaphragm. Simulations are steady state, and combustion derives from a single-phase chemical reaction. Liquid injection...