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Shchelkin Spiral
The Shchelkin spiral is a device that assists the transition from deflagration (subsonic combustion) to detonation in a pulse detonation engine. The spiral is named after Kirill Ivanovich Shchelkin, a Russian physicist who described it in his 1965 book ''Gas Dynamics of Combustion''. In pulse detonation engines, direct detonation of the combustible mixture can be relatively straightforward, but require more energy than when detonation is preceded by deflagration. The deflagration to detonation transition Deflagration to detonation transition (DDT) refers to a phenomenon in ignitable mixtures of a flammable gas and air (or oxygen) when a sudden transition takes place from a deflagration type of combustion to a detonation type of explosion. Descri ... (DDT) must however occur within the length of the detonation tube, which can be solved by providing the Shchelkin spiral. The Shchelkin spiral acts as an obstacle by creating a partial blockage of the detonation tube, effectively sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deflagration
Deflagration (Lat: ''de + flagrare'', "to burn down") is subsonic combustion in which a pre-mixed flame propagates through a mixture of fuel and oxidizer. Deflagrations can only occur in pre-mixed fuels. Most fires found in daily life are diffusion flames. Deflagrations with flame speeds in the range of 1 m/sec differ from detonations which propagate supersonically through shock waves with speeds in the range of 1 km/sec. Applications Deflagrations are often used in engineering applications when the goal is to move an object such as a bullet in a firearm, or a piston in an internal combustion engine with the force of the expanding gas. Deflagration systems and products can also be used in mining, demolition and stone quarrying via gas pressure blasting as a beneficial alternative to high explosives. Flame physics The underlying flame physics can be understood with the help of an idealized model consisting of a uniform one-dimensional tube of unburnt and burned gaseous fuel, sep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Detonation
Detonation () is a type of combustion involving a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. Detonations propagate supersonically through shock waves with speeds in the range of 1 km/sec and differ from deflagrations which have subsonic flame speeds in the range of 1 m/sec. Detonations occur in both conventional solid and liquid explosives, as well as in reactive gases. The velocity of detonation in solid and liquid explosives is much higher than that in gaseous ones, which allows the wave system to be observed with greater detail (higher resolution). A very wide variety of fuels may occur as gases (e.g. hydrogen), droplet fogs, or dust suspensions. In addition to dioxygen, oxidants can include halogen compounds, ozone, hydrogen peroxide and oxides of nitrogen. Gaseous detonations are often associated with a mixture of fuel and oxidant in a composition somewhat below conventional flammabil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kirill Ivanovich Shchelkin
Kirill Ivanovich Shchelkin (russian: Кирилл Иванович Щёлкин ) (17 May 1911 – 8 November 1968) was a Soviet physicist born in Georgia, with armenian origin, the former Soviet program of nuclear weapons who made theoretical and experimental contribution in combustion and gas dynamics. He was notable for his work on the in the detonation process of first Soviet nuclear weapon, the RDS-1, and the first thermonuclear device, and for his role as the first scientific director of the Soviet nuclear weapons development center in the Urals at Chelyabinsk-70. Life and career He was born in Tbilisi, Russian Empire, and baptised at home by a Russian Orthodox priest. He lived in the Caucasus as a young child. When he was aged seven, his family moved to Krasny, where his father – a land surveyor and his mother, a teacher, both of ethnic Russian extraction – came from. In 1924, his family moved to Karasubazar (now Belogorsk) in the Crimea because his father was suffe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fuel
A fuel is any material that can be made to react with other substances so that it releases energy as thermal energy or to be used for work. The concept was originally applied solely to those materials capable of releasing chemical energy but has since also been applied to other sources of heat energy, such as nuclear energy (via nuclear fission and nuclear fusion). The heat energy released by reactions of fuels can be converted into mechanical energy via a heat engine. Other times, the heat itself is valued for warmth, cooking, or industrial processes, as well as the illumination that accompanies combustion. Fuels are also used in the cells of organisms in a process known as cellular respiration, where organic molecules are oxidized to release usable energy. Hydrocarbons and related organic molecules are by far the most common source of fuel used by humans, but other substances, including radioactive metals, are also utilized. Fuels are contrasted with other substances or de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deflagration To Detonation Transition
Deflagration to detonation transition (DDT) refers to a phenomenon in ignitable mixtures of a flammable gas and air (or oxygen) when a sudden transition takes place from a deflagration type of combustion to a detonation type of explosion. Description A deflagration is characterized by a subsonic flame propagation velocity, typically far below , and relatively modest overpressures, typically below . The main mechanism of combustion propagation is of a flame front that moves forward through the gas mixture - in technical terms the reaction zone (chemical combustion) progresses through the medium by processes of diffusion of heat and mass. In its most benign form, a deflagration may simply be a flash fire. In contrast, a detonation is characterized by supersonic flame propagation velocities, perhaps up to , and substantial overpressures, up to . The main mechanism of detonation propagation is of a powerful pressure wave that compresses the unburnt gas ahead of the wave to a temp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ignition Systems
Ignition may refer to: Science and technology * Firelighting, the human act of creating a fire for warmth, cooking and other uses * Combustion, an exothermic chemical reaction between a fuel and an oxidant * Fusion ignition, the point at which a nuclear fusion reaction becomes self-sustaining * Ignition SCADA, software by Inductive Automation Arts and entertainment * ''Ignition'' (video game), a top-down racing game for PC published in 1997 * ''Ignition'' (2001 film), directed by Yves Simoneau * Ignition Entertainment, a computer video games company founded in 2002 * '' Ignition! An Informal History of Liquid Rocket Propellants'', (1972) by John Drury Clark Music Albums and EPs * ''Ignition'' (B1A4 album), 2012 * ''Ignition'' (Darude album), 2001 * ''Ignition'' (John Waite album), 1982 * ''Ignition'' (Mark Boals album), 1998 * ''Ignition'' (Nicky Romero album), 2014 * ''Ignition'' (The Offspring album), 1992 * ''Ignition'' (The Music Machine album) * ''Ignition!'', album ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Russian Inventions
This timeline of Russian Innovation encompasses key events in the history of technology in Russia, from the Grand Duchy of Moscow up to the Russian Federation. The entries in this timeline fall into the following categories: * indigenous inventions, like airliners, AC transformers, radio receivers, television, artificial satellites, ICBMs * uniquely Russian products, objects and events, like Saint Basil's Cathedral, Matryoshka dolls, Russian vodka * products and objects with superlative characteristics, like the Tsar Bomba, the AK-47, and the Typhoon-class submarine * scientific and medical discoveries, like the periodic law, vitamins and stem cells This timeline includes scientific and medical discoveries, products and technologies introduced by various peoples of Russia and its predecessor states, regardless of ethnicity, and also lists inventions by naturalized immigrant citizens. Certain innovations achieved internationally may also appear in this timeline in cases where the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soviet Inventions
This timeline of Russian Innovation encompasses key events in the history of technology in Russia, from the Grand Duchy of Moscow up to the Russian Federation. The entries in this timeline fall into the following categories: * indigenous inventions, like airliners, AC transformers, radio receivers, television, artificial satellites, ICBMs * uniquely Russian products, objects and events, like Saint Basil's Cathedral, Matryoshka dolls, Russian vodka * products and objects with superlative characteristics, like the Tsar Bomba, the AK-47, and the Typhoon-class submarine * scientific and medical discoveries, like the periodic law, vitamins and stem cells This timeline includes scientific and medical discoveries, products and technologies introduced by various peoples of Russia and its predecessor states, regardless of ethnicity, and also lists inventions by naturalized immigrant citizens. Certain innovations achieved internationally may also appear in this timeline in cases wher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
