Автор frigate, 14.01.2009 20:51:32
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ЦитироватьЦитата 2-х летней давности.Pratt & Whitney Wins Contract for Future Exploration In-Space Cryogenic Propulsion SystemWednesday June 29, 11:45 am ETWEST PALM BEACH, Fla., June 29 /PRNewswire-FirstCall/ -- Pratt & Whitney (P&W) Space Propulsion announced today that it has begun work on a multi-year $40 million program (including options) from NASA's Exploration Systems Mission Directorate to develop the Common Extensible Cryogenic Engine (CECE), a deep throttling 15 thousand-pound thrust-class demonstrator liquid-oxygen and hydrogen cryogenic rocket engine.Это что за двигатель такой? А то тут пишутьhttp://www.physorg.com/news103210759.htmlчто все ок!
ЦитироватьPratt & Whitney Wins Contract for Future Exploration In-Space Cryogenic Propulsion SystemWednesday June 29, 11:45 am ETWEST PALM BEACH, Fla., June 29 /PRNewswire-FirstCall/ -- Pratt & Whitney (P&W) Space Propulsion announced today that it has begun work on a multi-year $40 million program (including options) from NASA's Exploration Systems Mission Directorate to develop the Common Extensible Cryogenic Engine (CECE), a deep throttling 15 thousand-pound thrust-class demonstrator liquid-oxygen and hydrogen cryogenic rocket engine.
ЦитироватьA technology development engine that may help NASA safely return astronauts to the lunar surface has successfully completed its third round of testing. The goal of these tests is to reduce risk and advance technology for a reliable and robust rocket engine that could enable America's next moon landing.The tests by Pratt & Whitney Rocketdyne in West Palm Beach, Fla., helped gather data on this concept engine that might play a role in the next stage of human exploration of the moon. Most rockets make spacecraft travel faster. The goal of a lunar lander descent engine is to slow the vehicle so astronauts can land safely.The Common Extensible Cryogenic Engine, or CECE, is a deep-throttling engine, which means it has the flexibility to reduce thrust from 100 percent down to 10 percent — allowing a spacecraft to gently land on the lunar surface. The 13,800-pound thrust engine uses extremely cold liquid oxygen and liquid hydrogen as propellants.During the test, the engine was successfully throttled from a high of a 104 percent of the engine's potential down to eight percent, a record for an engine of this type. A cryogenic engine is needed to provide high performance and put more payload on the surface of the moon. The CECE demonstrator has evaluated two engine configurations during three rounds of hot-fire testing."The first test series in 2006 was a challenge but showed promise," said Tony Kim, Deep Throttling Engine project manager at NASA's Marshall Space Flight Center, Huntsville, Ala. "Testing in 2007 provided an in-depth examination of low-power-level throttling and engine performance characteristics. This third cycle we actively addressed and found solutions to the challenges we faced."The team carefully assessed test results that showed pressure oscillations in the engine at lower throttle levels called "chugging." Chugging may not be a concern for the engine itself, but the resulting vibrations could have the potential to resonate with the structure of the rocket and cause problems for the lander or crew.Injector and propellant feed system modifications successfully eliminated engine chugging by controlling liquid hydrogen and liquid oxygen flow to the combustion chamber. The latest engine configuration incorporates a new injector design and propellant feed system that carefully manages the pressure, temperature and flow of propellants."The technology developed from this effort will help engineers successfully design future cryogenic engines to meet the throttling requirements of the Constellation Program's Altair lunar lander," Kim said.The CECE is based on the existing Pratt & Whitney Rocketdyne RL10 upper stage rocket engine. Previous first-hand flight experience, as well as this data, will allow engineers to develop simulation models that can focus testing for efficiency and effectiveness.The CECE collaboration includes engineers from Marshall, NASA's Glenn Research Center in Cleveland, and Pratt & Whitney Rocketdyne. NASA has invested in CECE technology since 2005 as part of the Propulsion and Cryogenics Advanced Development project at Glenn. The project is funded by the Exploration Technology Development Program in NASA's Exploration Systems Mission Directorate.
ЦитироватьЭто наследник RL-10?http://cobweb.ecn.purdue.edu/~propulsi/propulsion/rockets/liquids/rl10.html
ЦитироватьThe CECE is based on the existing Pratt & Whitney Rocketdyne RL10 upper stage rocket engine. Previous first-hand flight experience, as well as this data, will allow engineers to develop simulation models that can focus testing for efficiency and effectiveness.
ЦитироватьНеет! Это практически самостоятельная разработка. Началась она еще в конце 80-х годов. Не знаю как сейчас (может у Frigate есть более свежая информация) но в 90-х годах в этом безгенераторном ЖРД возможность глубокого дросселирования достигалась за счет газификации обоих компонентов в рубашке охлаждения камеры и сопла. А также там турбина ТНА кислорода работала на газообразном кислороде, ну а водородный ТНА на водороде. Также там использовался дополнительный теплообменник для нагрева водорода. . У меня даже есть отчеты 91-94 годов по испытаниям этого ЖРД скачанные с сайта архива НАСА.
ЦитироватьEngine Model: RL-10A-5. Designer: Pratt and Whitney. Propellants: Lox/LH2. Thrust(vac): 64.700 kN (14,545 lbf). Thrust(sl): 54.800 kN (12,320 lbf). Isp: 373 sec. Isp (sea level): 316 sec. Burn time: 127 sec. Mass Engine: 143 kg (315 lb). Diameter: 1.02 m (3.33 ft). Length: 1.07 m (3.51 ft). Chambers: 1. Chamber Pressure: 39.12 bar. Area Ratio: 4.00. Oxidizer to Fuel Ratio: 6.00. Thrust to Weight Ratio: 46.85. Country: USA. First Flight: 1993. Last Flight: 1996. Flown: 48.Throttleable to 30% of thrust, sea level version of RL10. Four engines were built and were used on the McDonnell Douglas DC-X and the upgraded DC-XA VTOVL SSTO launch vehicle demonstrators.
ЦитироватьНАСА протестировало двигатель для лунной посадки (20:51) 14.01.2009В пресс-службе НАСА сегодня сообщили о завершении процесса тестирования нового ракетного двигателя, который будет использован по время посадки будущими лунными аппаратами. В ведомстве говорят, что двигатель Common Extensible Cryogenic Engine (CECE) прошел три раунда тестирования и в каждом к нему не было претензий.Эксперты отмечают, что большинство ракетных двигателей необходимы для того, чтобы разогнать космический аппарат, однако в случае CECE задача другая - он должен обеспечить медленную и плавную посадку тяжелого космического аппарата на песчаную поверхность Луны. Методика работы двигателя противоположна традиционным моделям - он начинает работать с полной мощности и постепенно сбрасывает ее до 10% от номинальной.В основе CECE находятся жидкие кислород и водород, охлажденные почти до минус 270 градусов.Во время тестов мощность двигателя варьировалась от 108% до 8% от номинальной мощности. "Данное устройство относится к классу криогенных двигателей и позволяет добиваться высокой эффективности, даже при большой нагрузке. Первые испытания CECE прошли в 2006 году и с тех пор двигатель выглядит многообещающе", - говорит проектный менеджер НАСА Тони Ким.
ЦитироватьThe CECE development contract, which was originally awarded in June 2005, extends through March 2009. During this next phase of the program, Pratt & Whitney Rocketdyne will design, manufacture and test a new, enhanced injector to support stable combustion at very low thrust.
ЦитироватьYes, you're seeing this image correctly. There are icicles forming at the rim of this rocket engine bell, and this particular engine generates a scalding 2,760 C (5,000 F) degree steam and a whopping 13,000 lbs of thrust. How can that happen? Cryogenics. NASA is developing the engines that will be used for the next generation lunar lander, the Altair. These engines are called the Common Extensible Cryogenic Engine (CECE). CECE is fueled by a mixture of -182 C (-297 F) liquid oxygen and -253 C (-423 F) liquid hydrogen. The engine components are super-cooled to similar low temperatures–and that's where the icicles come from. As CECE burns its frigid fuels, hot steam and other gases are propelled out the nozzle. The steam is cooled by the cold nozzle, condensing and eventually freezing to form icicles around the rim.
ЦитироватьИнтересно лед видеть на срезе сопла работающего ЖРД
ЦитироватьЦитироватьИнтересно лед видеть на срезе сопла работающего ЖРД :)Интересно, этот лед нужно учитывать как меняющий центровку при прилунении?
ЦитироватьИнтересно лед видеть на срезе сопла работающего ЖРД :)
ЦитироватьThe CECE achieved a throttling range from 104 percent down to 8 percent of its maximum power of 13,800 pounds of thrust.
ЦитироватьSpacecraft attempting to land on an unfamiliar surface need to perform a maneuver called "deep throttling" - a step that allows the vehicle to precisely throttle down to perform a smooth, controlled landing. NASA, in partnership with Pratt and Whitney Rocketdyne (PWR) headquartered in Canoga Park, Calif., has demonstrated this type of engine control capability to help design a more reliable and robust descent engine that could be used to land space explorationvehicles on the moon, an asteroid or another planet.The Common Extensible Cryogenic Engine, also known as CECE, recently completed the fourth and final series of hot-fire tests on a 15,000-pound thrust class cryogenic technologydemonstrator rocket engine, increasing the throttling capability by 35 percent over previous tests.This test series demonstrated this engine could go from a thrust range of 104 percent power down to 5.9 percent. This equates to an unprecedented 17.6:1 deep-throttling capability, which means this cryogenic engine can throttle up and back down quickly.Another key objective of this test series and a successful first for this type rocket engine was to test a closed loop control system using a fuel mixture ratio component that controls the amount of liquid oxygen and liquid hydrogen entering the combustion chamber.This system also monitors the combustion chamber pressure feedback during throttling. Precise control of propellant and thrust will reduce the amount of fuel needed to land future space vehicles, reducing launch cost and weight, opening more payload capability.Landing a space vehicle on an unknown location, can be a little like driving at night where unforeseen challenges present themselves and drivers have to be able to react quickly and accurately to avoid a collision. The same is true for a spacecraft when they come upon a rock or boulder before landing.The spacecraft has to be able to throttle up quickly and accurately to avoid damaging the craft. The CECE team has worked to increase the engine's ability to throttle quickly and precisely to decrease the risks associated with landing humans and expensive space hardware."An outstanding team of NASA and Pratt and Whitney Rocketdyne engineers worked diligently to get us to this milestone," said Tony Kim, Deep Throttling Engine Technology Development manager at NASA's Marshall Space Flight Center in Huntsville, Ala. "I couldn't be more pleased with the test results we achieved. Our collaborative teaming environment allowed our members to stretch the boundaries of engine operations."NASA will benefit from the advancements made to this technology, and I'm confident that the cosmos will be opened and available to humanity, in no small part, because of these achievements," said Frank Peri, director of the Exploration Technology Development Program at NASA's Langley Research Center, in Hampton, Va.The total test time for the technology demonstration 1.7 test series was 2,403 seconds, which, when combined with the previous three test series, brings the program's total engine test time to 7,436 seconds, or 124 minutes, providing a large amount of test data to quantify CECE performance and capability. All of the tests were conducted at a NASA owned; Pratt and Whitney Rocketdyne's operated facility in West Palm Beach, Fla.The CECE is based on the existing Pratt and Whitney Rocketdyne RL10 upper stage rocket engine. The previous RL10 track record as well as the recent technology demonstrations provides confidence and buys down risk for a possible future throttling engine development to support space exploration.The test data will allow engineers to develop simulation models to help predict engine behavior based on design parameters.The CECE collaborationincludes engineers from Marshall, NASA's Glenn Research Center in Cleveland, and Pratt and Whitney Rocketdyne. NASA has invested in CECE technology since 2005 as part of the Propulsion and Cryogenics Advanced Development project at Glenn. The project is funded by the Exploration Technology Development Program in NASA's Exploration Systems Mission Directorate.