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.

Coupled Analysis of Flow and Surface Ablation in Carbon-Carbon Rocket Nozzles

Abstract: A study is conducted to predict C/C nozzle recession behavior in solid rocket motors for broad variations of propellant formulations and motor operating conditions. The numerical model considers the turbulent flow in the nozzle, heterogeneous chemical reactions at the nozzle surface, variable transport and thermodynamic properties, and heat conduction in the nozzle material. Results show that the recession rate is largely determined by the diffusion of the major oxidizing species (H2O, CO2, OH) to the nozzle surface. Both the concentration of the major oxidizing species -affected by the aluminum content of the propellant- and the chamber pressure exert a strong influence on the recession rate. The erosion rate increases almost linearly with chamber pressure and decreases with propellants with higher aluminum content. The calculated results show a very good agreement with the experimental data from the BATES motor firings.

Rocket and Spacecraft Propulsion

Abstract: History and principles of rocket propulsion -- The thermal rocket engine -- Liquid propellant rocket engines -- Solid propellant rocket motors -- Launch vehicle dynamics -- Electric propulsion -- Nuclear propulsion -- Advanced thermal rockets.The revised edition of this practical, hands-on book discusses the range of launch vehicles in use today throughout the world, and includes the very latest details of some of the advanced propulsion systems currently being developed. The author covers the fundamentals of the subject, from the basic principles of rocket propulsion and vehicle dynamics through the theory and practice of liquid and solid propellant motors, to new and future developments. The revised edition will stick to the same principle of providing a serious exposition of the principles and practice of rocket propulsion, but from the point of view of the user and enquirer who is not an engineering specialist. Most chapters will remain substantially the same as the first edition; they will be updated where necessary and errata corrected. The main revisions will be to the chapter on electric propulsion where there have been significant new developments both in engine types and in practical applications. This is now seen as the key to planetary exploration by robotic probes and should therefore be reflected. Nuclear propulsion has emerged from the doldrums and is now seen as a definite possibility for outer solar system robotic exploration; and as enabling technology for a human mars expedition. A new chapter on nuclear thermal propulsion has been added to reflect this revival of interest.

MiniRocket: A Very Fast (Almost) Deterministic Transform for Time Series Classification

Abstract: Rocket achieves state-of-the-art accuracy for time series classification with a fraction of the computational expense of most existing methods by transforming input time series using random convolutional kernels, and using the transformed features to train a linear classifier. We reformulate Rocket into a new method, MiniRocket. MiniRocket is up to 75 times faster than Rocket on larger datasets, and almost deterministic (and optionally, fully deterministic), while maintaining essentially the same accuracy. Using this method, it is possible to train and test a classifier on all of 109 datasets from the UCR archive to state-of-the-art accuracy in under 10 minutes. MiniRocket is significantly faster than any other method of comparable accuracy (including Rocket), and significantly more accurate than any other method of remotely similar computational expense.

Investigation of Cryogenic Propellant Flames Using Computerized Tomography of Emission Images

Abstract: Cryogenic propellant combustion is investigated in this paper. It is shown that the mean e ame structure may be obtained by applying computerized tomography principles to oxygen‐ hydrogen (OH) emission images obtained from experiments on a shear coaxial injector. The data correspond to injection conditions typical of those found in rocket motors, but to lower operating pressures of 1, 5, and 10 bar. The transformed emission images yield the mean volumetric OH emission distribution. This quantity may be roughly interpreted as the mean volumetric rate of reaction. The data provide the location of the mean e ame zone and cone rm that stabilization takes place in the immediate vicinity of the injection plane. I. Introduction L IQUID oxygen ‐ gaseous hydrogen rocket engines have been used for a number of years because they yield the high specie c-impulse values needed in space propulsion applications. Cryogenic propellants thus diminish the cost per mass of payload in orbit, but pose specie c storage, handling, and operating problems. Current rocket motor design relies on extensive experience and technological expertise. The detailed processes involved in cyrogenic combustion are, however, not yet fully documented. An improved understanding of the mode of e ame stabilization and of the e ame structure in the near e eld of the injector head would be quite valuable. This information could be used to improve design methodologies and enhance reliability of operation. Such information would be useful for more accurate predictions of heat transfer rates to the engine walls. In this context, knowledge about whether the e ame is stabilized right on the injector lip or at a distance as a lifted e ame is of considerable interest. The stabilization region is specie cally investigated in this paper on the basis of experiments carried out on a cryogenic model scale combustor designated as Mascotte. This facility, operated by ONERA, is dedicated to basic research and technological studies. Data gathered at this facility include planar laser-induced e uorescence (LIF), planar laser light scattering, and emission imaging. Simultaneous recording of light elastic scattering and hydroxyl radical (OH) e uorescence images has allowed identie cation of the e ame stabilization. When the liquid oxygen (LOX) is injected by a central tube and is surrounded by an annulus of high-speed gaseous hydrogen, it is shown 1 that the e ame is established in the outer boundary of the LOX jet, where the hydrogen stream velocity is low. It is also found that the laser-induced OH ‐ e uorescence signal level remains in the same range over the zone visualized, with little change in the signal amplitude as a function of the axial distance. However, the emission images of the excited OH radical appear to yield a different picture of the e ame stabilization region. The emission amplitude is low close to the injector and increases rapidly at a distance. From these specie c features