Browse Topic: Liquid propellants
In the study of combustion characteristics of liquid rocket fuels, it is customary to either study the combustion of liquid fuel droplets or the combustion of fuel sprays. However, the two are closely related to each other, because in a typical rocket combustion chamber, the burning of droplets, droplet clusters, and fuel sprays occur simultaneously.
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.
NASA Stennis Space Center’s (SSC’s) large rocket engine test facility requires the use of liquid propellants, including the use of cryogenic fluids like liquid hydrogen as fuel, and liquid oxygen as an oxidizer (gases which have been liquefied at very low temperatures). These fluids require special handling, storage, and transfer technology. The biggest problem associated with transferring cryogenic liquids is product loss due to heat transfer. Vacuum jacketed piping is specifically designed to maintain high thermal efficiency so that cryogenic liquids can be transferred with minimal heat transfer.
Returning samples of Martian soil and rock to Earth is of great interest to scientists. There were numerous studies to evaluate Mars Sample Return (MSR) mission architectures, technology needs, development plans, and requirements. The largest propulsion risk element of the MSR mission is the Mars Ascent Vehicle (MAV). Along with the baseline solid-propellant vehicle, liquid propellants have been considered. Similar requirements apply to other lander ascent engines and reaction control systems.
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 discovery that nanostructured materials exhibit properties different than their bulk materials provided many exciting opportunities with technological applications. One such opportunity is the observed ignition of the single-walled carbon nanotubes (SWCNTs) with an ordinary camera flash. In this paper, light-activated ignition characteristics of the as-produced SWCNTs (50 wt% iron nanoparticle content) with a camera flash are presented. The primary objective of this work is to use nanostructured materials as means for distributed (or volumetric) ignition and improved combustion in propulsion systems. Important examples are homogeneous-charged compression ignition (HCCI) engines, liquid rocket fuel sprays, and enhanced flame stabilization in gas turbine engines. The idea was originally proposed by the author in April 2003 and the first patent filed in July 2004 following a series of initial investigations. Based on these and additional tests, this new ignition method is now
This SAE Aerospace Information Report (AIR) presents a review of the types and general characteristics of power sources that may be used to provide the power for gaseous or liquid fluidic control systems. Fluidic definitions, terminology, units and symbols are defined in Reference 2.1.1.
This Aerospace Recommended Practice outlines the design, installation, testing and field maintenance criteria for aerospace vehicle cryogenic duct systems. These recommendations are considered currently applicable guides and are subject to revision due to the continuing development within industry.
A class of self-adjusting injectors for spraying liquid oxidizers and/or fuels into combustion chambers has been proposed. The proposed injectors were originally intended for use in rocket-engine combustion chambers, but could also be used to improve control over flows of liquid propellants in other combustion chambers.
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.
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 SAE Aerospace Information Report (AIR) presents a review of the types and general characteristics of power sources that may be used to provide the power for gaseous or liquid fluidic control systems. Fluidic definitions, terminology, units and symbols are defined in Reference 2.1.1.
Precision X-Y stages were developed for integration into a new analytical measurement tool for use in the development of digital inks or other fluids to be jetted from ink jet print heads. The Drop Watcher III system provides repeatable and exact measurements of drop formation (e.g., distance and time from the start of the drop ejection), drop size, and flight characteristics of opaque or transparent fluid drops. In addition to X-Y stages, the system consists of a monochrome CCD camera with a zoom lens providing magnification from 0.75X to 4X. Magnification from 2.5X to 10X is achievable when using the high-magnification option, yielding fields of view from 640 µm to 2.56 mm.
A paper suggests the development of a hybrid rocket engine and associated equipment for returning a sample of material from Mars at relatively low cost. In a hybrid rocket engine, a solid fuel is burned by use of a liquid or gaseous oxidizer, the flow of which can be throttled to control the engine. Unlike conventional solid rocket propellants, a solid rocket fuel can be made relatively inert in the absence of the oxidizer and therefore presents little hazard of explosion or inadvertent ignition. Unlike conventional (and relatively expensive) liquid rocket propellants, a solid rocket fuel is not corrosive or susceptible to leakage. The solid fuel in the proposed system would be in granular form, packed into the rocket motor. Oxygen or another suitable oxidizer could be transported from Earth together with this solid fuel. Alternatively, oxygen could be generated from CO2 in the Martian atmosphere by use of in-situ resource utilization (ISRU) equipment. Inasmuch as ISRU is not yet a
This information report provides a short glossary of rocket ignition and related terms.
This AIR concerns itself with the end use of Fluidic (or Flueric) control hardware on aerospace vehicle applications. The fluidic control hardware application is viewed as a system comprised of the following subsystems: Power Source Power Conditioner Fluidic/Flueric Control(s) This AIR identifies potential power sources and relates the design of the fluidic/flueric controls to the nature of both the power source and, as required, the power conditioner. In the unlikely event that the power source yields a fluid which is always at the desired pressure level, temperature range and flow rate capacity and, further, is free of particulate or liquid contaminate, pressure pulsation, etc., no power conditioner is required. Experience has shown that the power conditioner is usually necessary to assure operability and reliability of the total control system. The functions of the fluidic power conditioner are analagous to those of the electrical power supply regulator circuit in an electrical
This report lists military and industry specifications and standards which are used in aerospace engine starting systems. Only those hardware standards which have been specifically designed for engine starting systems are listed. Revisions and amendments which are current for these specifications and standards are not listed.
SUBSTANTIAL POWER is necessary to start the modern jet engine. Thus, starting equipment has become a major concern of air transport operators. This paper discusses the equipment used with self-contained starting systems. The authors discuss and evaluate a variety of self-contained systems: combustor, fuel-air combustion, cartridge, liquid propellant, hydraulic supported by auxiliary power units, and electric supported by APU. Possible future systems are: self-breathing systems, oxygen combustors, and liquid-oxygen-water-fuel combustors. It is emphasized that the choice of a starting system for a particular aircraft will depend on aircraft characteristics and the aircraft's intended use.*
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