Topic
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.
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TL;DR: An intuitive, linearized model of a TVC –EMA system is presented along with practical and accurate methods of estimating the model parameters, and nonlinearities are discussed and simulated.
Abstract: Increased use of electromechanical actuators (EMA) in high-power, ight-critical applications where hydraulics have traditionally been employed has increased the need for accurate, measurable models of the EMA-load systems. Thrust vector control (TVC) of rocket engines is such an application. An intuitive, linearized model of a TVC –EMA system is presented along with practical and accurate methods of estimating the model parameters. The estimation techniques are a combination of calculations using engineering design data and of experiments based on rst principles that are designed to isolate the effects of speci c parameters and/or combinations of parameters. The techniques use measurements that are commonly available in an EMA system and inputs that are easily generated with either a computer or signal generator. The validity of the model and the parameter estimation techniques are experimentally veri ed with a pendulum simulator of a rocket engine and an EMA designed for TVC. Nonlinearities are discussed and simulated, and resonance shifting caused by backlash is demonstrated with experimental data.
29 citations
Patent•
21 Jul 1999
TL;DR: In this paper, a new process for developing high regression rate propellants for application to hybrid rockets and solid fuel ramjets is described, which involves the use of a criterion to identify propellants which form an unstable liquid layer on the melting surface of the propellant.
Abstract: This invention comprises a new process for developing high regression rate propellants for application to hybrid rockets and solid fuel ramjets. The process involves the use of a criterion to identify propellants which form an unstable liquid layer on the melting surface of the propellant. Entrainment of droplets from the unstable liquid-gas interface can substantially increase propellant mass transfer leading to much higher surface regression rates over those that can be achieved with conventional hybrid propellants. The main reason is that entrainment is not limited by heat transfer to the propellant from the combustion zone. The process has been used to identify a new class of non-cryogenic hybrid fuels whose regression rate characteristics can be tailored for a given mission. The fuel can be used as the basis for a simpler hybrid rocket design with reduced cost, reduced complexity and increased performance.
29 citations
TL;DR: In this paper, film cooling is considered a prerequisite for the safe operation of future high-performance rocket engines and wall normal or inclined cooling-gas injection into a laminar boundary-layer airflow is considered.
Abstract: Film cooling is considered a prerequisite for the safe operation of future high-performance rocket engines Wall-normal or inclined cooling-gas injection into a laminar boundary-layer airflow at Ma
29 citations
TL;DR: Results of ten rocket soundings conducted from Kronogard, Sweden, and Barrow, Alaska, during the summers of 1963 through 1965 indicate that a temperature of 150�K or less is a necessary but not sufficient condition for the existence of noctilucent clouds.
Abstract: Mesospheric temperature possible relationship to occurence of noctilucent clouds studied using rocket soundings
29 citations
TL;DR: In this article, a strategy for the simulation of turbulent internal flows in a solid rocket motor (SRM) is described and sources of turbulence inside an SRM are identified and their dominance relative to each other is characterized to set a priority in the modeling effort.
Abstract: A strategy for the simulation of turbulent internal flows in a solid rocket motor (SRM) is described Sources of turbulence inside an SRM are identified and their dominance relative to each other is characterized to set a priority in the modeling effort This complex problem is simplified by subdividing it into problem components allowing for a more detailed study of each component Problems of interest in which investigations have been pursued are compressible periodic rockets, spatial transition in a laboratory-scale rocket, and effect of inhibitors and large-eddy simulation (LES) wall-layer modeling (WLM) for the nozzle boundary layer Grid sensitivity is observed in the application of dynamic LES to a transitional flow in an SRM Inhibitors at the segment juctions act as a trip in the transition to turbulence and play a more dominant role compared to the injection of turbulence from the propellant surface Detached-eddy simulation provides relatively accurate wall gradient properties and is more generally applicable than WLM This hybrid method, however, requires some degree of implicitness in the time discretization to be efficient
29 citations