Air-independent propulsion ( AIP ) is a marine propulsion technology that allows non-nuclear submarines to operate without access to atmospheric oxygen (by coating or using a snorkel). AIP may supplement or replace a non-nuclear diesel-electric propulsion system.
The United States Navy uses the "SSP" stomach classification symbol to designate AIP-supported vessels while retaining the "SSK" for classic electric diesel attack submarines.
Modern non-nuclear submarines are potentially more hidden than nuclear submarines; the nuclear vessel reactor must constantly pump the coolant, producing a certain amount of noise that can be detected (see acoustic signals). Non-nuclear submarines that operate on battery power or AIP, on the other hand, can be completely silent. While nuclear-powered designs still dominate during submerged periods and deepwater performance, low-tech non-nuclear attack submarines are extremely effective in coastal operations and pose a significant threat to less-concealed and less maneuverable nuclear submarines.
AIP is usually implemented as an additional source, with traditional diesel engines handling surface propulsion. Most of these systems produce electricity which in turn drives an electric motor to drive or recharge the boat battery. This submarine electrical system is also used to provide "hotel services" - ventilation, lighting, heating, etc. - though this consumes a small amount of power compared to that required for propulsion.
AIP can be reassembled into an existing submarine by entering additional stomach parts. AIP typically does not provide durability or power to replace atmospheric dependent drivers, but allows submerged longer than conventional driven submarines. Conventional power plants generally provide a maximum of 3 megawatts, and an AIP source of about 10% of it. A nuclear submarine propulsion plant is usually much larger than 20 megawatts.
Video Air-independent propulsion
Histori
In the development of submarines, the problem of finding a satisfactory form of propulsion under water has lasted a long time. The earliest submarines were human-powered with a hand-cranked propeller, which quickly used the air inside; these ships must move for most of the time on the surface with open hatches, or use some form of respiratory tube, both inherently dangerous and result in a number of initial accidents. Then, the ship is mechanically driven using compressed air or vapor, or electricity, which must be recharged from the shore or from an on-board aerobic machine.
The earliest efforts on fuel to be burned anaerobically were in 1867, when NarcÃÆ's Monturiol succeeded in developing anaerobic or chemically driven independent aerospace steam engines.
In 1908 the Russian Imperial Navy launched a Pochtovy submarine using a gasoline engine fed with compressed air and underwater fatigue.
Both of these approaches, the use of fuels that provide energy for open cycle systems, and the provision of oxygen to aerobic engines in closed cycles, characterize AIP today.
Maps Air-independent propulsion
Type
Open cycle system
During World War II, the German company Walter experimented with submarines using concentrated hydrogen peroxide as a source of oxygen under water. It uses a steam turbine, using steam heated by burning diesel fuel in the vapor/oxygen atmosphere created by the decomposition of hydrogen peroxide by potassium permanganate catalyst.
Several experimental vessels were produced, although the work did not mature to a decent warship. One disadvantage is the instability and scarcity of the fuel involved. Another is that while the system produces high underwater speeds, it is wasteful with fuel; the first vessel, V-80 , requires 28 tons of fuel to travel 50 nautical miles, and the final design is slightly better.
After the war of a Type XVII ship, U-1407 , which had been traced back to the end of World War II, was rescued and handed back to the Royal Navy as HMS
The Soviet Union also experimented with technology and an experimental boat was built that used hydrogen peroxide in a Walter machine.
The United States also received a Type XVII vessel, U-1406 , and then used hydrogen peroxide in an experimental dwarf submarine, X-1 . It was initially supported by hydrogen peroxide/diesel engines and battery systems until the explosion of hydrogen peroxide supply on May 20, 1957. X-1 was later converted to diesel electricity.
The Soviet Union, Britain and the United States, the only country known to experiment with technology at the time, left it when the latter developed a nuclear reactor small enough for submarine propulsion. Other countries, including Germany and Sweden, will then restart the development of AIP.
It was retained to encourage torpedoes by Britain and the Soviet Union, despite being hastily abandoned by the former following the tragedy of HMSÃ, Sidon . Both this and the loss of the Russian submarine Kursk are due to accidents involving torpedoes powered by hydrogen peroxide.
Closed cycle diesel engine
This technology uses submarine diesel engines that can be operated conventionally on the surface, but which can also be supplied with oxidants, usually stored as liquid oxygen, when submerged. Because the machine's metal will burn in pure oxygen, oxygen is usually diluted with recycle flue gas. Argon replaces the exhaust when the engine is turned on.
In the late 1930s the Soviet Union experimented with closed cycle engines, and a number of small class M vessels were built using the REDO system, but nothing was resolved before the German invasion of 1941.
During World War II, Kriegsmarine experimented with such a system as an alternative to Walter's peroxide system, designing variants of their XVII type vessels and their Type XXVIIB Seehund submarine, Type XVIIK and Type XXVIIK respectively, though not resolved before the end of the war.
After the war, the Soviet Union developed a small class submarine with a capacity of 650 tons consisting of thirty built between 1953 and 1956. It has three diesels - two conventional and one closed cycle using liquid oxygen.
In the Soviet system, called a "single propulsion system", oxygen is added after the flue gas has been filtered through a chalk-based chemical absorber. Submarines can also run dieselnya using a snorkel. Quebec has three driving shafts: diesel 32D 900Ã, bhp (670 kW) on the central shaft and two M-50P 700 b bhp (520Ã, kW) diesel on the outer shaft. In addition, a 100-hp "creep" motor (75-kW) is coupled to the central axis. Boats can be run at slow speeds using only midline diesels.
Since liquid oxygen can not be stored indefinitely, these ships can not operate away from the base. That is dangerous; at least seven submarines were explosive, and one of them, M-256 , drowned following an explosion and a fire. They are sometimes nicknamed cigarette lighter. The last submarine using this technology was canceled in the early 1970s.
The German Navy Type 205 submarine U-1 is equipped with an experimental 3,000 hp (2,200 kW) unit.
Closed cycle steam turbine
The French MESMA system (Module d'Energie Sous-Marine Autonome) is offered by the French shipyard DCNS. MESMA is available for Agosta 90B and ScorpÃÆ'¨ne-class submarines. This is essentially a modified version of their nuclear propulsion system with heat generated by ethanol and oxygen. In particular, conventional steam turbine power plants are supported by steam generated from ethanol combustion and stored oxygen at atmospheric pressure. These pressures enable the disposal of carbon dioxide to be discharged into the sea at any depth without a compressor.
Each MESMA system costs about $ 50-60 million. As it is installed on ScorpÃÆ'¨nes, it requires the addition of 8.3-meters (27Ã, ft), 305 tons of hull parts to the submarine, and results in a submarine capable of operating for more than 21 days under water, depending on variables such as speed.
An article in Undersea Warfare Magazine notes that: "although MESMA can provide higher output power than other alternatives, inherent efficiency is the lowest of the four AIP candidates, and the rate of oxygen consumption is also higher. "
Engine drive cycle
Swedish shipbuilder Kockums built three Gotland submarines for a Swedish Navy equipped with an additional Stirling engine that burns liquid oxygen and diesel fuel to power a 75-kilowatt electric generator for either power or battery charging. The boat's durability of 1,500 tonnes is about 14 days at 5 kn (5.8 mph, 9.3 km/h).
Kockums has also updated/upgraded class VIII-VÃÆ'¤stergÃÆ'¶tergÃÆ'¶tland submarines with the AIP Styling plugin section. Two ( SÃÆ'¶dermanland and ÃÆ' â € "stergÃÆ'¶tland ) operates in Sweden as the SÃÆ'¶dermanland class, and the other two are in service in Singapore as Archer ( Archer and Swordsman class).
Kockums also sends a Stirling machine to Japan. The new Japanese submarine will all be equipped with a Stirling engine. The first submarine in class, S? Ry? , was launched on December 5, 2007 and delivered to the navy in March 2009.
The new Swedish A26 submarine has the AIR Stirling system as its primary energy source. The submerged durability will be more than 18 days at 5 knots using AIP.
Fuel cell
Siemens has developed a 30-50 kilowatt fuel cell unit, a device that converts chemical energy from fuel to electricity. Fuel cells differ from batteries because they require continuous fuel sources (such as hydrogen) and oxygen to maintain chemical reactions, carried in vessels in pressurized tanks. Nine of these units were incorporated into the Howaldtswerke submarine of Deutsche Werft AG U-31 , the flagship vessel for Type 212A of the German Navy. Other vessels of this class and AIP export submarine are equipped with HDW (Dolphin class , Type 209 mod and Type 214) using two 120 kW modules (160 hp), also from Siemens.
After the success of Howaldtswerke Deutsche Werft AG in its export activities, some builders developed a fuel cell helper unit for submarines, but in 2008 no other shipyards had contracts for submarines that were equipped.
The AIP implemented in the Spanish Navy's S-80 class is based on a bioethanol processor (provided by Hynergreen of Abengoa, SA) consisting of a reaction chamber and several intermediate coprox reactors, which convert BioEtOH into high purity hydrogen. This output provides a series of fuel cells from UTC Power (which also supplies fuel cells for the Space Shuttle).
The reformers are fed with bioethanol as fuel, and oxygen (stored as a liquid in a high pressure cryogenic tank), produces hydrogen as a sub-product. The resulting hydrogen and more oxygen are fed to the fuel cell.
The Indian Defense Research and Development Organization has developed an AIP-based Phosphoric Acid Fuel Cell (PAFC) system to power two submarines of Calvary-the last class based on the ScorpÃÆ'¨ne design.
The Portuguese Tridente Portuguese submarine submarine is also equipped with fuel cells.
Nuclear power
Air-independent propulsion is a term normally used in the context of improving the performance of a conventionally-driven submarine. However, as an additional power supply, nuclear power falls into AIP's technical definition. For example, a proposal to use a small 200 kilowatt reactor for additional power - collected by the AECL as a "nuclear battery" - could improve the submarine capability of a Canadian submarine.
Nuclear reactors have been used since 1950 to drive submarines. The first submarine was the USS Nautilus commissioned in 1954. Currently, China, France, India, Russia, the United Kingdom and the United States are the only countries to successfully build and operate nuclear-powered submarines.
Non-nuclear AIP submarine
In 2017, about 10 countries are building AIP submarines with nearly 20 countries that operate AIP-based submarines:
References
Note
Further reading
Thornton, LCDR Grant B. (1994). Design Tool for Evaluation of Atmospheric Independent Drive in Submarine (PDF) (M.S. Sea Assembly Engineering and Marine Engineering and M.S. Mechanical Engineering). Massachusetts Institute of Technology. Ã, Whitman, Edward C. (Fall 2001), "Air-Independent Repair: AIP Technology Makes New Lower Threats", Undersea Warfare , Undersea Warfare United States Navy (13), archived from the original on December 8, 2007Source of the article : Wikipedia
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