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.

Propellant Injector Influence on Liquid-Propellant Rocket Engine Instability

Abstract: The avoidance of acoustic instabilities, which may cause catastrophic failure, is demanded for liquid-propellant rocket engines. This occurs when the energy released by combustion amplifies acoustic disturbances; it is therefore essential to avoid such positive feedback. Although the energy addition mechanism operates in the combustion chamber, the propellant injector system may also have considerable influence on the stability characteristics of the overall system, with pressure disturbances in the combustion chamber propagating back and forth in the propellant injectorchannels.Theintroducedtimedelaymayaffectstability,dependingontheratioofthewavepropagationtime throughtheinjectortotheperiodofthecombustionchambersacousticmodes.Thisstudyfocusesontransverse-wave liquid-propellant rocket engine instabilities using a two-dimensional polar coordinate solver (with averaging in the axial direction) coupled to one-dimensional solutions in each of the coaxial oxygen–methane injectors. A blockage in one (or more) of the injectors is analyzed as a stochastic event that may cause an instability. A properly designed temporaryblockage of oneor more injectors can also be used for control of an oscillation introduced by any physical event.Thestochasticanddesignvariablesparameterspaceis exploredwiththepolynomial chaosexpansionmethod.

Solid propellant rocket motor case for insensitive munitions requirements

Abstract: The invention is a propellant rocket motor case designed to meet insensitive munitions requirements comprising a propellant surrounded by a case having slots therein, and a wrapping around the case, the wrapping comprising a load bearing material which can withstand the hoop load on the case during normal firing of said rocket, the material also having the characteristic of losing strength or melting at undesired temperatures above normal storage temperatures, but below the autoignition temperature of said propellant, so that during undesired high storage temperatures the propellant will exhaust any subsequently generated gases, due to any subsequent propellant burning, by venting through said slots thereby avoiding any explosion or undesired operative one-way thrust.

Theoretical and experimental analysis of liquid layer instability in hybrid rocket engines

Abstract: The combustion behavior of different hybrid rocket fuels has been analyzed in the frame of this research. Tests have been performed in a 2D slab burner configuration with windows on two sides. Four different liquefying paraffin-based fuels, hydroxyl terminated polybutadiene (HTPB) and high-density polyethylene (HDPE) have been tested in combination with gaseous oxygen (GOX). Experimental high-speed video data have been analyzed manually and with the proper orthogonal decomposition (POD) technique. Application of POD enables the recognition of the main structures of the flow field and the combustion flame appearing in the video data. These results include spatial and temporal analysis of the structures. For liquefying fuels these spatial values relate to the wavelengths associated to the Kelvin Helmholtz Instability (KHI). A theoretical long-wave solution of the KHI problem shows good agreement with the experimental results. Distinct frequencies found in the POD analysis can be related to the precombustion chamber configuration which can lead to vortex shedding phenomena.