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Pulsed Rocket Motors
A pulsed rocket motor is typically defined as a multiple pulse solid-fuel rocket motor. This design overcomes the limitation of solid propellant motors being unable to be easily shut down and reignited. The pulse rocket motor allows the motor to be burned in segments (or pulses) that burn until completion of that segment. The next segment (or pulse) can be ignited on command by either an onboard algorithm or in pre-planned phase. All of the segments are contained in a single rocket motor case as opposed to staged rocket motors. The pulsed rocket motor is made by pouring each segment of propellant separately. Between each segment is a barrier that prevents the other segments from burning until ignited. At ignition of a second pulse the burning of the propellant generally destroys the barrier. The benefit of the pulse rocket motor is that by the command ignition of the subsequent pulses, near optimal energy management of the propellant burn can be accomplished. Each pulse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulse (physics)
In physics, a pulse is a generic term describing a single disturbance that moves through a transmission medium. This medium may be vacuum (in the case of electromagnetic radiation) or matter, and may be indefinitely large or finite. Pulse reflection Consider a pulse moving through a medium - perhaps through a rope or a slinky. When the pulse reaches the end of that medium, what happens to it depends on whether the medium is fixed in space or free to move at its end. For example, if the pulse is moving through a rope and the end of the rope is held firmly by a person, then it is said that the pulse is approaching a fixed end. On the other hand, if the end of the rope is fixed to a stick such that it is free to move up or down along the stick when the pulse reaches its end, then it is said that the pulse is approaching a free end. Free end A pulse will reflect off a free end and return with the same direction of displacement that it had before reflection. That is, a pulse with a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrust Level
Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that system. The force applied on a surface in a direction perpendicular or normal to the surface is also called thrust. Force, and thus thrust, is measured using the International System of Units (SI) in newtons (symbol: N), and represents the amount needed to accelerate 1 kilogram of mass at the rate of 1 meter per second per second. In mechanical engineering, force orthogonal to the main load (such as in parallel helical gears) is referred to as static thrust. Examples A fixed-wing aircraft propulsion system generates forward thrust when air is pushed in the direction opposite to flight. This can be done by different means such as the spinning blades of a propeller, the propelling jet of a jet engine, or by ejecting hot gases from a r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Pulse Propulsion
Nuclear pulse propulsion or external pulsed plasma propulsion is a hypothetical method of spacecraft propulsion that uses nuclear explosions for thrust. It originated as Project ''Orion'' with support from DARPA, after a suggestion by Stanislaw Ulam in 1947. Newer designs using inertial confinement fusion have been the baseline for most later designs, including Project ''Daedalus'' and Project ''Longshot''. History Los Alamos Calculations for a potential use of this technology were made at the laboratory from and toward the close of the 1940s to the mid 1950s. Project Orion Project Orion was the first serious attempt to design a nuclear pulse rocket. A design was formed at General Atomics during the late 1950s and early 1960s, with the idea of reacting small directional nuclear explosives utilizing a variant of the Teller–Ulam two-stage bomb design against a large steel pusher plate attached to the spacecraft with shock absorbers. Efficient directional explosives maximi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atomized Fuel
Atomization refers to breaking bonds in some substance to obtain its constituent atoms in gas phase. By extension, it also means separating something into fine particles, for example: process of breaking bulk liquids into small droplets. Atomization may also refer to: Science and technology * The making of an aerosol, which is a colloidal suspension of fine solid particles or liquid droplets in a gas * An apparatus using an atomizer nozzle * Spray (liquid drop), Sprays, mists, fogs, clouds, Mineral dust, dust clouds and smoke, which appear to be atomized * A nebulizer, which is a device used to administer medication in the form of a mist inhaled into the lungs * An electronic cigarette construction of electronic cigarettes#Atomizer and tank, atomizer is a component which employs a heating element to vaporize a flavored solution, that may or may not contain nicotine, for inhalation into the lungs * The conversion of a vaporized sample into atomic components in atomic spectroscopy S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jet Engine
A jet engine is a type of reaction engine discharging a fast-moving jet of heated gas (usually air) that generates thrust by jet propulsion. While this broad definition can include rocket, Pump-jet, water jet, and hybrid propulsion, the term typically refers to an internal combustion airbreathing jet engine such as a turbojet, turbofan, ramjet, or pulse jet engine, pulse jet. In general, jet engines are internal combustion engines. Airbreathing jet engines typically feature a Axial compressor, rotating air compressor powered by a turbine, with the leftover power providing thrust through the propelling nozzle—this process is known as the Brayton cycle, Brayton thermodynamic cycle. Jet aircraft use such engines for long-distance travel. Early jet aircraft used turbojet engines that were relatively inefficient for subsonic flight. Most modern subsonic jet aircraft use more complex High-bypass turbofan, high-bypass turbofan engines. They give higher speed and greater fuel eff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulse Jet Engine
300px, Diagram of a pulsejet A pulsejet engine (or pulse jet) is a type of jet engine in which combustion occurs in pulses. A pulsejet engine can be made with few or no moving parts, and is capable of running statically (i.e. it does not need to have air forced into its inlet, typically by forward motion). The best known example may be the Argus As 109-014 used to propel Nazi Germany's V-1 flying bomb. Pulsejet engines are a lightweight form of jet propulsion, but usually have a poor compression ratio, and hence give a low specific impulse. There are two main types of pulsejet engines, both of which use resonant combustion and harness the expanding combustion products to form a pulsating exhaust jet that produces thrust intermittently. The first is known as a valved or traditional pulsejet and it has a set of one-way valves through which the incoming air passes. When the air-fuel is ignited, these valves slam shut, which means that the hot gases can only leave through the engin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nozzle Throat
A nozzle is a device designed to control the direction or characteristics of a fluid flow (specially to increase velocity) as it exits (or enters) an enclosed chamber or pipe. A nozzle is often a pipe or tube of varying cross sectional area, and it can be used to direct or modify the flow of a fluid ( liquid or gas). Nozzles are frequently used to control the rate of flow, speed, direction, mass, shape, and/or the pressure of the stream that emerges from them. In a nozzle, the velocity of fluid increases at the expense of its pressure energy. Types Jet A gas jet, fluid jet, or hydro jet is a nozzle intended to eject gas or fluid in a coherent stream into a surrounding medium. Gas jets are commonly found in gas stoves, ovens, or barbecues. Gas jets were commonly used for light before the development of electric light. Other types of fluid jets are found in carburetors, where smooth calibrated orifices are used to regulate the flow of fuel into an engine, and in jacuzzis o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Burn Time
A burn is an injury to skin, or other tissues, caused by heat, cold, electricity, chemicals, friction, or ultraviolet radiation (like sunburn). Most burns are due to heat from hot liquids (called scalding), solids, or fire. Burns occur mainly in the home or the workplace. In the home, risks are associated with domestic kitchens, including stoves, flames, and hot liquids. In the workplace, risks are associated with fire and chemical and electric burns. Alcoholism and smoking are other risk factors. Burns can also occur as a result of self-harm or violence between people (assault). Burns that affect only the superficial skin layers are known as superficial or first-degree burns. They appear red without blisters and pain typically lasts around three days. When the injury extends into some of the underlying skin layer, it is a partial-thickness or second-degree burn. Blisters are frequently present and they are often very painful. Healing can require up to eight weeks and scarri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Combustion
Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combustion does not always result in fire, because a flame is only visible when substances undergoing combustion vaporize, but when it does, a flame is a characteristic indicator of the reaction. While the activation energy must be overcome to initiate combustion (e.g., using a lit match to light a fire), the heat from a flame may provide enough energy to make the reaction self-sustaining. Combustion is often a complicated sequence of elementary radical reactions. Solid fuels, such as wood and coal, first undergo endothermic pyrolysis to produce gaseous fuels whose combustion then supplies the heat required to produce more of them. Combustion is often hot enough that incandescent light in the form of either glowing or a flame is produced. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solid-fuel Rocket
A solid-propellant rocket or solid rocket is a rocket with a rocket engine that uses solid propellants ( fuel/oxidizer). The earliest rockets were solid-fuel rockets powered by gunpowder; they were used in warfare by the Arabs, Chinese, Persians, Mongols, and Indians as early as the 13th century. All rockets used some form of solid or powdered propellant up until the 20th century, when liquid-propellant rockets offered more efficient and controllable alternatives. Solid rockets are still used today in military armaments worldwide, model rockets, solid rocket boosters and on larger applications for their simplicity and reliability. Since solid-fuel rockets can remain in storage for an extended period without much propellant degradation and because they almost always launch reliably, they have been frequently used in military applications such as missiles. The lower performance of solid propellants (as compared to liquids) does not favor their use as primary propulsion in mode ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barrier
A barrier or barricade is a physical structure which blocks or impedes something. Barrier may also refer to: Places * Barrier, Kentucky, a community in the United States * Barrier, Voerendaal, a place in the municipality of Voerendaal, Netherlands * Barrier Bay, an open bay in Antarctica * Barrier Canyon, the former name of Horseshoe Canyon (Utah) * Barrier Lake, Alberta, Canada * Barrier Mountain, the former name of Mount Baldy (Alberta) * Barrier Ranges, a mountain range in New South Wales, Australia * Division of Barrier, a former Australian Electoral Division in New South Wales * The Barrier, a lava dam in British Columbia, Canada * The Barrier (Kenya), an active shield volcano in Kenya * The Barrier, a common synonym for the city of Broken Hill, New South Wales * The Barrier, an early name for the Ross Ice Shelf, Antarctica In arts and entertainment Film * ''The Barrier'' (1917 film), a lost 1917 American silent drama film * ''The Barrier'' (1926 film), a silent film * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multi-stage Rocket
A multistage rocket or step rocket is a launch vehicle that uses two or more rocket ''stages'', each of which contains its own engines and propellant. A ''tandem'' or ''serial'' stage is mounted on top of another stage; a ''parallel'' stage is attached alongside another stage. The result is effectively two or more rockets stacked on top of or attached next to each other. Two-stage rockets are quite common, but rockets with as many as five separate stages have been successfully launched. By jettisoning stages when they run out of propellant, the mass of the remaining rocket is decreased. Each successive stage can also be optimized for its specific operating conditions, such as decreased atmospheric pressure at higher altitudes. This ''staging'' allows the thrust of the remaining stages to more easily accelerate the rocket to its final speed and height. In serial or tandem staging schemes, the first stage is at the bottom and is usually the largest, the second stage and subsequ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
