Browse Topic: Solid propellants
Strategies to control solid rocket propellant regression rate require a robust throttling technique applicable to high performance propellant formulations. Currently, several methods to control and throttle either motors or subscale propellant strands exist, including chamber pressure control (e.g. pintle nozzles or rapid depressurization quench), infrared laser irradiation of the burning surface to increase burning rates, development of inherently unstable combustion chamber geometries (producing either local pressure or velocity perturbations), and electrically sensitive hydroxylammonium nitrate (HAN)-based formulations in which burning rate is controlled by a voltage potential. However, these techniques are limited in that they either can only be used with low flame temperature (low specific impulse) propellants, result in low propulsion system mass fraction (pintle), are only capable of producing a single perturbation, or are formulation specific.
The purpose of this SAE Information Report is to provide basic information on penetrating radiation, as applied in the field of nondestructive testing, and to supply the user with sufficient information so that he may decide whether penetrating radiation methods apply to his particular inspection need. Detailed information references are listed in Section 2.
The scope of this SAE Information Report is to provide general information relative to the nature and use of infrared techniques for nondestructive testing. The document is not intended to provide detailed technical information, but will serve as an introduction to the theory and capabilities of infrared testing and as a guide to more extensive references.
Structural analysis of solid rocket motors is challenging for several reasons, but the most important of these is the complex behavior of the propellant. The mechanical response of a solid propellant is time and temperature dependent. The complexity of the mathematical analysis of the propellant depends on the loading conditions, but for some loading situations, the linear viscoelasticity assumption is reasonable. In particular, linear viscoelasticity is perhaps the most appropriate material behavior description for use in the simulations of stresses related to storage conditions. Typically, simulations use a viscoelastic model in the form of a Prony series and a Williams–Landel–Ferry (WLF) equation. The parameters in these models are derived from stress relaxation experiments, making the stress relaxation experiment a key viscoelastic test, analogous to the tensile test for linear elastic materials.
This SAE Aerospace Information Report (AIR) presents an overview of the application and control of fixed and variable displacement pumps with the emphasis on the controls most commonly used on variable displacement pumps. It describes various options to control the operation of hydraulic pumps in terms of controlling the pump output pressure and/or flow and assisting in the selection of the pump.
The Space Station Integrated Kinetic Launcher for Orbital Payload Systems (SSIKLOPS), also known as “Cyclops,” deployed the largest satellite ever from the International Space Station (ISS) on November 28, 2014. The satellite, SpinSat, a Naval Research Laboratory (NRL)/Department of Defense Space Test Program (DoD STP) satellite, is pioneering the utilization of electronically controlled solid propellant thrusters as well as acquiring vital atmospheric density data. It is a spherical satellite 22 inches in diameter, weighing 115 pounds, and will remain in orbit for over two years.
Various gas systems are classified in a broad sense, component operation is described in moderate detail, pertinent design parameters are discussed, and possible modes for system operation are listed.
Gas, for the purpose of this ARP, shall be defined as the gaseous product(s) resulting from the decomposition, dissociation, or combustion of liquid or solid mono or bi-propellants. Where other gases such as heated N2, H2, H2O (steam), etc., which may have similar physical and/or chemical properties as the defined "gas", are used to effect testing economics, they may he considered as being included in this ARP.
The scope of this document is to provide a list of documents of types pertaining to the effects of oxygen on ignition and combustion of materials. Consolidating these references in one place makes it easier to find documents of this type as these references are difficult to locate.
Much of the available long-term storage test data has been reviewed and topically separated to enable the independent discussion of storage effects on fluids, seals, hydraulic components, and hydraulic systems. Comments are made in Section 4 concerning the applicability of the test results and regarding design practices for storability. Conclusions are drawn in Section 5 regarding inactive storage of hydraulic systems for at least a 7 year period.
It is intended that this SAE Aerospace Recommended Practice (ARP) will set down guidelines for the development and test of gas motors to provide a practical and reliable hot gas rotary actuation mechanism. Specific operational and test requirements shall be specified in a detail specification.
This information report presents a preliminary discussion of liquid propellant gas generation (LPGG) systems. A LPGG system, as used herein, is defined as a system which stores a liquid propellant and, on command, discharges and converts the liquid propellant to a gas. The LPGG system can interface with a gas-to-mechanical energy conversion device to make up an auxiliary power system. Figure 1 shows a block diagram of LPGG system components which include a propellant tank, propellant expulsion system, propellant control and a decomposition (or combustion) chamber. The purpose of this report is to provide general information on the variety of components and system arrangements which can be considered in LPGG design, summarize advantages and disadvantages of various approaches and provide basic sizing methods suitable for initial tradeoff purposes.
This interface standard applies to fuzes/fuzing systems (referred to as fuzing system hereafter) in airborne weapons that use a MIL-STD-1760 type interface. It defines the powers, the discrete signals and the serial data interface for the communications at the interface between the fuzing system and the remainder of the weapon, including the weapon control unit. The Class 1 interface is an electrical only interface that facilitates use of MIL-STD-1760 type platform store interfaces for the fuze to monitor intentional release and defines the fuze interface bus communications protocol to allow sending and receiving data from fuzing systems. Class 2 interfaces add a defined connector and additional interfaces to facilitate the exchange of compatible fuzing systems. Class 3 interfaces add further interface definitions to facilitate the exchange of AS5680A compatible fuzing systems components. The bus communications protocol provides a means by which the weapon may set mission parameters
This interface standard applies to fuzes/fuzing systems (referred to as fuzing system hereafter) in airborne weapons that use a MIL-STD-1760 interface. It defines the powers, the discrete signals and the serial data interface for the communications at the interface between the fuzing system and the remainder of the weapon, including the weapon control unit, for Class 1 interfaces. Future issues of the standard will provide for additional fuzing system related functionality defined as Class 2 and Class 3 interfaces. For future issues of this standard, the connector definition is contained in AS5680. This standard does not impose any safety requirements and does not supersede or replace any existing applicable safety standards.
Much of the available long-term storage test data has been reviewed and topically separated to enable the independent discussion of storage effects on fluids, seals, hydraulic components, and hydraulic systems. Comments are made in Section 4 concerning the applicability of the test results and regarding design practices for storability. Conclusions are drawn in Section 5 regarding inactive storage of hydraulic systems for at least a 7 year period.
Various gas systems are classified in a broad sense, component operation is described in moderate detail, pertinent design parameters are discussed, and possible modes for system operation are listed.
Gas, for the purpose of this ARP, shall be defined as the gaseous product(s) resulting from the decomposition, dissociation, or combustion of liquid, or solid mono or bi-propellants. Where other gases such as heated N2, H2, H2O (steam), etc., which may have similar physical and/or chemical properties as the defined "gas", are used to effect testing economies, they may be considered as being included in this ARP.
It is intended that this SAE Aerospace Recommended Practice (ARP) will set down guidelines for the development and test of gas motors to provide a practical and reliable hot gas rotary actuation mechanism. Specific operational and test requirements shall be specified in a detail specification.
This information report presents a preliminary discussion of liquid propellant gas generation (LPGG) systems. A LPGG system, as used herein, is defined as a system which stores a liquid propellant and, on command, discharges and converts the liquid propellant to a gas. The LPGG system can interface with a gas-to-mechanical energy conversion device to make up an auxiliary power system. Figure 1 shows a block diagram of LPGG system components which include a propellant tank, propellant expulsion system, propellant control and a decomposition (or combustion) chamber. The purpose of this report is to provide general information on the variety of components and system arrangements which can be considered in LPGG design, summarize advantages and disadvantages of various approaches and provide basic sizing methods suitable for initial tradeoff purposes.
The scope of this document is to provide a list of documents of types pertaining to the effects of oxygen on ignition and combustion of materials. Consolidating these references in one place makes it easier to find documents of this type as these references are difficult to locate.
Missile pumps are categorized by a moderate testing life and a relatively short operational service life. Generally, the pumps are operated at higher speeds, temperatures, and pressures than those used in manned aircraft systems, yet reliability must be extremely high, since there rarely is a redundant system aboard the missile. Due to the short but critical life and performance requirements, development, reliability and acceptance testing should be focussed on eliminating infant mortality failures.
Marshall Aerospace Vehicle Representation in C (MAVERIC) is a computer program for generic, low-to-high-fidelity simulation of the flight(s) of one or more launch vehicle(s) or spacecraft. MAVERIC is designed to accommodate multi-staged vehicles, powered serially or in parallel, with multiple engines, tanks, and cargo elements. Engines can be of jet or conventional rocket types, using either liquid or solid propellants.
A dual-pulse laser (DPL) technique has been demonstrated for generating laser-induced sparks (LIS) to ignite fuels. The technique was originally intended to be applied to the ignition of rocket propellants, but may also be applicable to ignition in terrestrial settings in which electric igniters may not be suitable. Laser igniters have been sought as alternatives to such conventional devices as electrical spark plugs and torch igniters for the following main reasons:
NASA narrows its search for a successor to the Space Shuttle. NASA is another step closer to defining the next-generation reusable space transportation system. The first review of the Space Launch Initiative (SLI), a NASA-wide effort defining future space transportation systems, has been completed, narrowing the field of potential candidates for a new space transportation system. Dependable, long-life engines, along with crew escape and survival systems, and long-life, lightweight integrated airframes are among the SLI's highest priorities. Each greatly impacts the program's bottom line of increased safety, reliability, and cost-effectiveness.
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