Showing papers on "Propellant published in 1987"

Gas cushion impact protection device for motor vehicles

Abstract: The bottom wall (12) of a rectangular housing (10) comprises a trough-like depression (14) which is sealed on the inside of the housing (10) by a cover (22) provided with a securing flange (22A). A propellant charge (42) is introduced into the trough-like depression (14). The housing (10) is sealed at its front side by a covering formed by two pivotal foamed material plates (30, 32). In the interior of the housing (10) a folded gas bag (26) is accommodated which is inflated by the gases forming on combustion of the propellant charge (42) and flowing through gas passage openings of the cover (22) into the interior of the gas bag (26). Since the propellant charge (42) can be introduced directly or using a simple capsule housing of plastic into the interior of the trough (14) a separate and involved gas generator housing can be dispensed with.

Tool and process for stimulating a subterranean formation

Abstract: A high energy gas fracturing tool for radially fracturing a rock formation in a well bore consisting of a cylindrical canister that is holed to pass gas and is for housing a stack of propellant modules that are selected to provide a desired burn rate when ignited. Each propellant module mating face is angled from the horizontal between forty-five (45) to seventy-five (75) degrees, and the modules are bonded together with an epoxy resin wherein propellant or explosive particles are mixed, the resin to exhibit burn characteristics similar to those of the propellant stack. The tool, additional to the propellant containing canister, an ignitor rod and explosive device for igniting the propellant stack, mounts a bull head end over a lower end and a reverse thruster assembly that is connected to the canister upper end. The reverse thruster assembly includes a housing with nozzles formed therein that are angled from the vertical to pass gas on propellant deflagration, creating thereby a force against the tool lifting during propellant burning. Above the reverse thruster assembly is arranged a pressure pulse monitor that is battery powered to operate a pressure transducer for sensing pressure pulses at the tool. The monitor to turn on when a sufficient strength of pressure pulse is received, to store pressure pulses sensed over time, with the stored pressure data retrieved when the tool is removed from the well bore. The recorded pressure pulse data is used for determining the dynamic window of the formation, whereat, at a certain pressure over time the formation will be optimally radially fractured. The tool is suspended from the surface on a wire line and includes a collar locator for locating it at a certain level within the well bore.

Porous propellant grain and method of making same

Abstract: A process for preparing a porous propellant grain which comprises blending at least two combustible materials to form a homogeneous mixture, adding a predetermined amount of a liquid dispersant to said mixture to form a slurry, and flash drying the slurry in order to form a porous, single grain propellant having a greatly increased burning surface. A single grain propellant is produced having a flat, torroidal shape with a central cylindrical core and honeycombed with a plurality of porous channels extending entirely through the grain to increase the burning surface thereof.

Combustion Process of Mg/TF Pyrotechnics

Abstract: The combustion process of pyrotechnics was studied in order to obtain informations of the rate control parameters of burning rate. The pyrotechnics tested was made of Mg (magnesium) and TF (polyfluoroethylene). The burning rate measurements revealed that the burning rate of the Mg/TF propellants (pellet in shape) increases with increasing the weight fraction (ξ) of Mg in the range of ξ > 0.33. Though the adiabatic flame temperature is the maximum at ξ = 0.33, the burning rate increases with decreasing the flame temperature. The total burning surface area of the Mg particles mixed with in the unit mass of propellant plays an important role on the oxidation process in the gas phase just above the propellant burning surface. The heat flux feedback from the gas phase to the propellant burning surface increases with increasing ξ. Therefore, the burning rate increases as ξ increases.

Space launch vehicle

Abstract: A rocket launch vehicle comprising a rocket body having a forward section and an aft section, a first rocket engine fixedly mounted to the aft section of the rocket body and axially aligned with the rocket body, a second rocket engine detachably mounted to the aft section of the rocket body and aligned axially parallel with the first rocket engine, a third rocket engine detachably mounted to the aft section of the rocket body and aligned axially parallel with the first rocket engine and being on the side of the first rocket engine opposite the second rocket engine, a first recovery structure fastened to the second rocket engine, a second recovery structure attached to the third rocket engine, and a plurality of propellant supply tanks connected to the first, second, and third rocket engines. Each of the rocket engines is a Space Shuttle main engine. The propellant tanks are detachably mounted to the exterior of the rocket body. Fuel tanks are affixed to the interior of the aft section of the rocket body and communicate with the first rocket engine. The recovery structure includes a parachute deployment arrangement for selective deployment of a parachute within a reentry vehicle fixedly attached to each of the second and third rocket engines. The forward section of the rocket body is a modified Titan 4 payload fairing.

Laser-induced fluorescence in high pressure solid propellant flames

Abstract: The application of laser-induced fluorescence (LIF) to the study of high pressure solid propellant flames is described. The distribution of the OH and CN radicals was determined in several solid propellant flames at pressures up to 3.5 MPa. The greatest difficulty in these measurements was the separation of the desired LIF signals from the large scattering at the laser wavelength from the very optically thick propellant flames. Raman experiments using 308-nm excitation were also attempted in the propellant flames but were unsuccessful due to LIF interferences from OH and NH.

Passive propellant management system

Abstract: A passive propellant management system for a spacecraft liquid propellant tank (1) comprises several preferably V-shaped channels (2) which communicate liquid propellant from regions within the tank (1) to an outlet port (8), which expels liquid propellant but not pressurant gas. A liquid/bubble chamber assembly (9) couples the channels (2) with the outlet port (8). The channels (2) comprise relatively open portions (11) and relatively closed portions (10). In the relatively open portions (11), liquid is retained in a gap (12) between open ends of the V channels (2) and the inner wall of the tank (1). In the relatively closed portions (10), a screen, mesh or perforated plate (14) covers the open end of the V channels (2), intermediate the V channels (2) and the inner wall of the tank (1). The placement of the relatively open and closed portions (11, 10, respectively) is intentionally preselected based upon mission requirements. Where pressurant gas ullage is expected to be present, e.g., during periods of high g, relatively open portions (11) are used. Where liquid propellant is expected to be present, e.g., during periods of relatively low g, relatively closed portions (10) are used. The liquid/bubble chamber assembly (9) comprises a liquid trap (27) and bubble trap (28), which operate synergistically with each other and with the channels (2) to provide optimum liquid flow during all phases of the spacecraft mission.

Ram accelerator direct launch system for space cargo

Abstract: The ram accelerator, a chemically-propelled mass driver, is presented as a new approach for directly launching acceleration-insensitive pay-loads into LEO. The cargo vehicle resembles the centerbody of a conventional ramjet and travels through a launch tube filled with a premixed gaseous fuel and oxidizer mixture. The tube acts as the outer cowling of the ramjet and the combustion process travels with the vehicle. Two modes of ram accelerator drive are described, which when used in sequence, are capable of accelerating the cargo vehicle to 10 km/sec. The requirements for placing a 2000 kg vehicle with 50 percent payload fraction into a 400 km orbit, with a minimum of on-board rocket propellant for circularization maneuvers, are examined. It is shown that aerodynamic heating during atmospheric transit results in very little ablation of the nose. Both direct and indirect orbital insertion scenarios are investigated, and a three-step maneuver consisting of two burns and aerobraking is found to minimize the on-board propellant mass. A scenario involving a parking orbit below the desired final orbit is suggested as a means to increase the flexibility of the mass launch concept.

Energetics of Propellants, Fuels and Explosives; a chemical valence approach

Abstract: A simple approach involving the chemical valences of the fuel and the oxidizer elements present in a combustible mixture is described to evaluate the energetics related parameters of propellants, fuels and explosives. It simplifies the stoichiometric balancing of complex combustion equations, and provides an easy method of calculating the elemental stoichiometric coefficient. The method correctly predicts whether a mixture is fuel-lean, fuel-rich or stoichiometrically balanced. The calorimetric value of various stoichiometrically balanced combustible systems has been shown to be linearly dependent upon their total oxidizing (or reducing) valences. This relationship has been used successfully to evaluate the calorific value of fossil fuels. For fuel-rich explosives, a new valence dependent parameter has been derived which is found to be related with properties such as detonation velocity, heat of explosion and impact sensitivity.

Liquid propellant gun

Abstract: This invention provides a liquid propellant gun embodying a first species of this invention wherein the inner differential area piston is controlled by a variable damping mechanism, and both pistons have respective cross-sectional areas coupled to the pumping chamber.

Direct measurement of high frequency, solid propellant, pressure-coupled admittances

Abstract: This paper presents an experimental method that is capable of directly measuring solid propellant pressurecoupled responses at the high frequencies associated with tangential mode instabilities inside solid propellant rocket motors. The method utilizes a magnetic flowmeter to measure the velocity oscillation above a burning propellant surface simultaneously with a pressure oscillation measurement within an externally excited combustion chamber. A magnetic flowmeter burner was designed and constructed to evaluate this method of pressurecoupled response measurement. Response measurements were obtained for two formulations of AP/HTPB composite propellant at pressure oscillation frequencies of 4000 and 8000 Hz. The measurement data displayed repeatable trends in both the real and imaginary parts of the pressure-coupled response function.

Field Emission Electric Propulsion: Emission Site Distribution of Slit Emitters

Abstract: Field emission electric propulsion is the technological application of the principle of liquid metal ion sources as thrusters in electric space propulsion. Research work sponsored by the European Space Agency (ESA) on a slit-type field ion thruster is reported and discussed. The most significant new features of its emission performance are as follows: For the first time, a slit emitter with a closed propellant supply system was fired in any optional direction, requiring, in principle, no gravitational forces. Quantitative data relating the constituents of the residual gas atmosphere to the wetting behavior of the liquid metal propellant and the emission site distribution were obtained. A homogeneous distribution of equally spaced emission sites was observed; the measured spacing is in good agreement with a simple hydrostatic model of wavelike instabilities on electrically stressed surfaces of fluids.

System for controlling rotational speed of hydraulically driven cooling fan of internal combustion engine, responsive to engine coolant and also fan propellant temperature

Abstract: A cooling fan for an internal combustion engine hydraulically driven by a flow of propellant hydraulic fluid is controlled of its rotational speed by a system which includes a device for sensing a value representing the operating temperature of the engine, a device for sensing the operating temperature of the propellant hydraulic fluid, and a device for controlling the flow of the propellant hydraulic fluid, so as to increase the flow rate of the propellant hydraulic fluid when the operating temperature of the engine increases and also when the operating temperature of the propellant hydraulic fluid increases.

Two-liquid propulsive system for an artificial satellite and utilization of said system for ejecting the satellite

Abstract: The two-liquid propulsive system for an artificial satellite is characterized in that the components of the propellant are unequally distributed in at least two pairs of tanks (12, 16) and (14, 18) which are associated in such a way as to provide additional fuel in a first pair of tanks and additional oxidizer in a second pair of tanks, and in that the different pairs of tanks are suitable for being used in succession during predetermined time periods so that the exhaustion of a first propellant component in one tank (14 or 16) indicate that the residual normal lifetime of the satellite is at best approximately equal to said predetermined time period, and that after exhaustion of the second propellant component in the tank (16 or 14), the two tanks (12 and 18) each containing an excess quantity of one of the propellant components are associated in order to extract the satellite.

Influence of fuel temperature on atomization performance of pressure-swirl atomizers

Abstract: The influence of fuel temperature on mean drop size and drop-size distribution is examined for aviation gasoline and diesel oil using three pressure-swirl simplex nozzles. Spray characteristics are measured over wide ranges of fuel injection pressure and ambient air pressure using a Malvern spray analyzer. Fuel temperatures are varied from 20+ 50°C. Over this range of temperature, the overall effect of an increase in fuel temperature is to reduce the mean drop size and broaden the drop-size distribution in the spray. Generally, it is found that the influence of fuel temperature on mean drop size is far more pronounced for diesel oil than for gasoline. For both fuels, the beneficial effect of higher fuel temperatures on atomization quality is sensibly independent of ambient air pressure.

Dry aerosol foam

Abstract: A pressurized aerosol composition containing zeolite, surfactant, water and propellant in prescribed amounts and ratios which, upon discharge from an aerosol container, produces a characteristically dry foam.

High solids ratio solid rocket motor propellant grains and method of construction thereof

Abstract: A high acceleration high performance solid rocket motor grain such as for a ballistic defense missile or rocket assisted projectile comprises a propellant material which includes a highly plasticized binder so that the grain has a solids ratio equal to at least about 95 percent. In order that the grain with such a solids ratio may have adequate strength and withstand high acceleration forces, a reticulated structure is embedded therein. A method of constructing a rocket motor having such a grain is also disclosed.

Method of preserving a composite material cased solid propellant rocket motor

Abstract: A solid propellant rocket motor casing fabricated from strong filament in a matrix of curable polymer known in the trade as a composite motor casing is protected against permeation therethrough over long periods of time of water vapor from the atmosphere by a thin, lightweight, metal foil barrier comprising a metal foil adhesively backed tape such as aluminum foil tape spirally wrapped over the cylindrical or regular surface areas and by a separate, lightweight, metallic shell or dome having a thickness of 0.005 to 0.008 inches adhesively bonded onto the dome ends of the composite material cased solid propellant rocket motor, each metallic shell or dome being made by the use of a plastic or other destructible mold which is first coated with metal by an ion-vapor deposition process to a thickness of less than 0.005 inches, the thickness of the coating being subsequently increased by an electro-chemical coating process after which the mold is separated from the metal shell which then is adhesively bonded to the loaded rocket motor composite casing.

Laser thermal propulsion

Abstract: Laser thermal propulsion (LTP) is studied for the case in which laser power is absorbed by a small very high-temperature plasma (about 20,000 K) and transferred to the remainder of the pure hydrogen propellant by radiation and mixing. This concept could lead to the realization of a lightweight orbital transfer vehicle propulsion system having a specific impulse in the range 1000-2000 s. Approximately 12 percent of the input power may be radiated to the thruster walls, and 15 percent of the total propellant flow must be heated to 20,000 K to provide a bulk temperature of 5000 K prior to expansion. Three principal research issues identified are: (1) conditions for hydrogen plasma ignition, (2) control of the plasma position within the laser beam, plasma stability, and plasma absorption efficiency, and (3) characterization of the mixing of the plasma and buffer flows.

Apparatus for recoilless firing of projectiles from a lauching tube

Abstract: An apparatus for recoilless firing of projectiles from a launching tube comprises within the launching tube a forward brake ring, a forward sabot, a propellant charge with an ignition element or screw, a rear sabot, a counter-mass, and a rear brake ring, arranged within the launching tube in the sequence listed. Upon ignition of the propellant charge, high acceleration forces are created by the ensuing high peak pressures, which consequently requires a robust construction. In order to avoid this drawback, according to the invention the aforementioned disadvantage can be eliminated by using a propellant charge comprising a first cylindrical propellant charge body and a second annular propellant charge body which surrounds this first cylindrical propellant charge body.

Mass and power estimates for Mars in-situ propellant production systems

Abstract: An in-situ propellant production (ISPP) concept, a method for producing oxygen from carbon dioxide in the Martian atmosphere, is evaluated. The concept considered here employs zirconia membrane technology to separate O2 from CO2. Several options which can improve the reliability of the CO2/O2 ISPP system and also reduce the mass and power requirements are examined, and it is noted that the use of absorption pumps and advanced zirconia membranes significantly improves system reliability by eliminating the rotating turbomachinery of mechanical pumps. Mass and power requirements of ISPP systems designed to produce O2 only from CO2 (for an unmanned Mars mission) and to produce both CO and O2 from CO2 (for a manned Mars mission) are evaluated.

Liquid Propellant Guns

Abstract: : Liquid propellants have been the focus of periodic research efforts since just after the Second World War. Early efforts centered on the mechanically simple bulk loaded liquid propellant gun. A large number of experimental gun firings were conducted, and semi-quantitative models of the bulk loaded interior ballistic process were developed. However, the ballistic control required of a practical gun system has been achieved. In contrast, the regenerative liquid propellant gun has demonstrated the required ballistic control, but at the expense of mechanical complexity heretofore unknown in gun systems. Nevertheless, the regenerative liquid propellant gun may provide the mechanism for the development of a practical weapon system based on a liquid gun propellant.