Merlin-1

[Александр Ч.]

.

[Salo]

http://spacenews.com/ses-rethinking-being-first-to-fly-on-a-full-throttle-falcon-9/

Second Thoughts about Being First

SpaceX has been working since then to coax more thrust out of the Merlin 1D engine, which the company said before the SES-8 launch was operating at only 85 percent of its potential.
In a briefing with reporters here Jan. 22, SES officials said they retain full confidence in SpaceX and have seen the data showing the Merlin 1D engine's improved performance on the ground.
But the SES-9 satellite scheduled for launch this year is not SES-8, and the cost-benefit trade-offs on whether to be the first to trust your satellite to an upgraded rocket engine are not the same, either, said Martin Halliwell, SES's chief technical officer.
"The situation we have now with SpaceX is that we are awaiting manifest updates," Halliwell said. "You know SpaceX is introducing into their manifest a new engine, or a modification of the current engine, with about a 20 percent increase in thrust. We're making a decision internally as to whether we want to be the first to fly it."
SES-9, a Boeing Space and Intelligence Systems 702-HP spacecraft expected to weigh 5,300 kilograms at launch, is near the limit of what the current Falcon 9 v1.1 vehicle can carry and was to be placed into a subsynchronous orbit.SES-9 then would use its on-board propulsion to climb to final geostationary orbit.
SES-9 carries 81 transponder, 53 of which are designed to capture new business in the Indian Ocean region, including maritime customers, from is operating slot at 108.2 degrees east.

[Salo]

Интересно, как форсировли? Подняли давление до 120 атм?

[Salo]

http://spaceflightnow.com/2015/02/22/100th-merlin-1d-engine-flies-on-falcon-9-rocket/

100th Merlin 1D engine flies on Falcon 9 rocket       
Posted on February 22, 2015 by Stephen Clark  

File photo of a Merlin 1D engine. Credit: SpaceX
 
Depending on how you count it, SpaceX launched its 100th kerosene-fueled Merlin 1D rocket engine on a Falcon 9 rocket Feb. 11, underscoring what it says is an accelerated flight regime for the centerpiece of the company's propulsion shop.
The Falcon 9 rocket uses 10 Merlin engines on every mission — nine standard Merlin 1D powerplants on the launcher's first stage and a single modified Merlin 1D optimized for firing outside the atmosphere on the second stage.
If you're a purist, the 100th flight of a Merlin 1D engine on the Falcon 9's booster stage will come this weekend with the launch of two communications spacecraft for Eutelsat and Asia Broadcast Satellite — a mission currently targeted for no sooner than Feb. 27.
Accounting for Merlin 1D flights in all its variants, the 100th unit of the engine flew Feb. 11 when a Falcon 9 rocket blasted off from Cape Canaveral with NOAA's Deep Space Climate Observatory.
The Merlin 1D burns a mixture of kerosene and liquid oxygen, and it is an upgrade of previous Merlin engine versions flown in a base configuration on earlier Falcon 9 rockets and the lightweight Falcon 1 launcher.
At sea level, the engine generates 147,000 pounds of thrust at sea level, rising to 161,000 pounds in vacuum.
The upper stage derivative of the Merlin 1D engine is fitted with a larger nozzle for in-space firings.
The Merlin 1D engines fly on SpaceX's Falcon 9 v1.1 rocket and will power the company's Falcon Heavy launcher when it makes its first flight later this year.
SpaceX says the Merlin 1D engine has the highest thrust-to-weight ratio — 155-to-1 — of any operational booster engine. The Falcon 9 rocket's nine main engines together burn about 540 gallons of propellant per second, enough to drain a typical home swimming pool in less than a minute.

Nine Merlin 1D engines power the first stage of the Falcon 9 rocket, as seen in this file photo from a July 2014 launch. Credit: SpaceX
 
In a press release last year touting the production of the 100th Merlin 1D engine, SpaceX said it produced an average of four engines per week at the company's headquarters and fabrication center in Hawthorne, California.
The engine has a near-perfect flight history, with only one minor hiccup on record when an upper stage Merlin 1D engine failed to re-ignite on the Falcon 9 v1.1's first test flight. The issue occurred after the rocket successfully deployed all its satellite payloads in orbit, when SpaceX attempted to demonstrate a restart capability needed for future launches.
SpaceX says the Merlin 1D's flight heritage exceeds the records amassed by engines used on rival launch vehicles.
The hydrogen-burning Aerojet Rocketdyne RS-68 and RS-68A engines used on United Launch Alliance's Delta 4 rockets have successfully flown 44 times, and the Russian-made RD-180 engine has a flawless record of 58 launches on Atlas rockets since May 2000.
Production variants of Aerojet Rocketdyne's RL10 upper stage engine used on Atlas, Delta, Titan and Saturn rockets have flown 455 times since the 1960s.

Follow Stephen Clark on Twitter: @StephenClark1.

[cavia]

Salo пишет:
Интересно, как форсировли? Подняли давление до 120 атм?

Исходя из того, что они не сменили модель двигателя (1D), (единственное, что я встречал в качестве отличия от стандартной модели, это добавление литеры "+"    . двигатель получил минимальные конструктивные изменения (возможно на уровне ТНА или форсунок). но если не были изменены габариты камеры сгорания (иначе бы назвали его 1E  ) , то единственное за счет чего можно изменить тягу это как Вы правильно сказали , увеличить давление в камере сгорания. Похоже прочностные характеристики элементов  двигаеля изначально взяты с большим запасом.

Но это лишь мои предположения.

[triage]

Salo пишет:
http://spaceflightnow.com/2015/02/22/100th-merlin-1d-engine-flies-on-falcon-9-rocket/

100th Merlin 1D engine flies on Falcon 9 rocket       
Posted on February 22, 2015 by Stephen Clark

на заголовок было дежа вю

 http://www.spacex.com/news/2014/10/16/spacex-completes-100th-merlin-1d-engine
October 22, 2014
SPACEX COMPLETES 100TH MERLIN 1D ENGINE

только в октябре про производство, а сейчас про его запуск

[cavia]

http://www.b14643.de/Spacerockets_2/United_States_2/Falcon-IX/Merlin/index.htm

[Владимир Шпирько]

Двигатель проектировался как многоразовый,  двумя, тремя запусками за один полет....  Ракета - фактически одноразовая, посадка не планируется, даже её имитация, второго и последующих полетов не будет.   И запуск в полете только один - можно и запас прочности  использовать...  Удивительно другое - что за 5 лет впервые использовали ракету, как одноразовую - какой она и на данный момент и является.

[Salo]

cavia пишет:
http://www.b14643.de/Spacerockets_2/United_States_2/Falcon-IX/Merlin/index.htm

По ходу Норберт завысил вакуумный УИ и тягу у 1D.

 

[Salo]

cavia пишет:

Salo пишет:
Интересно, как форсировли? Подняли давление до 120 атм?

Исходя из того, что они не сменили модель двигателя (1D), (единственное, что я встречал в качестве отличия от стандартной модели, это добавление литеры "+"    . двигатель получил минимальные конструктивные изменения (возможно на уровне ТНА или форсунок). но если не были изменены габариты камеры сгорания (иначе бы назвали его 1E ) , то единственное за счет чего можно изменить тягу это как Вы правильно сказали , увеличить давление в камере сгорания. Похоже прочностные характеристики элементов двигаеля изначально взяты с большим запасом.

Но это лишь мои предположения.

Пишут, что переходят на переохлаждённые компоненты топлива, что позволит увеличить РЗТ при неизменном объёме баков и массовый расход через ТНА при неизменном объёме прокачки. Давление в КС естественно возрастёт.

http://space.stackexchange.com/questions/8009/what-is-changing-between-the-merlin-1d-engine-and-the-uprated-merlin-1d-engine
 

There isn't a lot of publicly available information.
I think they are planning to subcool the LOX in addition to the fuel. The increased density results in an increased propellant mass flow rate for the same turbopump speed. This will give increased chamber pressure and thus higher thrust and probably higher Isp. Hardware changes to the engine might include stronger thrust chamber structure - or they might use up some of the margin built into the existing structure. Likewise, perhaps the regenerative cooling will need to be improved. They might or might not increase the turbopump speed also, to further increase propellant mass flow rate.
Because the thrust increase was always planned for, some or all of these changes may have been anticipated at the time of the original engine design so they might not need to be made.

[Salo]

Salo пишет:

cavia пишет:
 http://www.b14643.de/Spacerockets_2/United_States_2/Falcon-IX/Merlin/index.htm

По ходу Норберт завысил вакуумный УИ и тягу у 1D.

Впрочем эти цифры он взял тут:
http://forum.nasaspaceflight.com/index.php?topic=32983.msg1131598#msg1131598
https://docs.google.com/spreadsheet/ccc?key=0Av6Zu8Wm_3cqdEdrRVZHenVYMWxNX0gzRVNGN2tVWlE&usp=drive_web#gid=7

[cavia]

Salo пишет:
 

There isn't a lot of publicly available information.
I think they are planning to subcool the LOX in addition to the fuel. ...

Это он так полагает,  не думаю, что охладив Liquid oxygen (куда его еще охлаждать, дальше плотность практически не меняется насколько я помню в плоть до кристаллизации ) или может керосин ( температура начала кристаллизации керосина -50 градуов), можно на 20 процентов поднять эффективность конкретного двигателя.

The increased density results in an increased propellant mass flow rate for the same turbopump speed

Думаю уменьшится в объеме он не более,чем на 0.01% или меньше, что пренебрежимо мало.

А если им это и каким то образом удастся сделать, я имею ввиду значительно увеличить плотность компонентов, то увеличится и стартовая масса. как бы ракета не развалилась  

Хотя возможно, я в чем то ошибаюсь.

[Salo]

Плотность компонентов можно поднять на 10%.
Обсуждали здесь: http://novosti-kosmonavtiki.ru/forum/forum13/topic7898/

[Salo]

Плотность RP-1 при охлаждении до -39°С возрастает с 820 кг/м3 до 867 кг/м3.
Плотность ЖК при переохлаждении до -209°С возрастает с 1140 кг/м3 до 1262 кг/м3.
При соотношении компонентов Км=2,36 получаем увеличение плотности топлива с 1021 кг/м3 до 1111 кг/м3, или на 8,8%. 

[Salo]

Из первоисточника о форсировании Merlin-1D:
http://shitelonsays.com/transcript/spacex-ses-8-pre-launch-conference-2013-11-24

With respect to the future potential for the rocket, I do think we've got.. I'm really happy with this rocket design. It's an incredibly capable vehicle. It's actually one of the biggest rockets in the world, it's worth noting, at about 1.3 million pounds of thrust, and we're only actually operating the engines at about 85% of their potential. Down the road, in future missions, we anticipate being able to crank them up to their full thrust capability, which would give about 165,000 pounds of sea-level thrust per engine.

[cavia]

Salo пишет:
Плотность RP-1 при охлаждении до -39°С возрастает с 820 кг/м3 до 867 кг/м3.
Плотность ЖК при переохлаждении до -209°С возрастает с 1140 кг/м3 до 1262 кг/м3.

Интересные цифры, по ссылке про их происхождение ничего нет. За керосином этого не замечал, но все возможно. В будущем буду покупать керосин в самые морозные дни  

[Salo]

"Как много нам открытий чудных готовит просвещенья дух..." (с) А.С.Пушкин.
Переохлаждённое топливо использовали ещё на Н-1.

[Salo]

cavia пишет:

Salo пишет:
Плотность RP-1 при охлаждении до -39°С возрастает с 820 кг/м3 до 867 кг/м3.
Плотность ЖК при переохлаждении до -209°С возрастает с 1140 кг/м3 до 1262 кг/м3.

Интересные цифры, по ссылке про их происхождение ничего нет.

Были тут dunnspace.com
В кэше возможно остались.

[Искандер]

Falcon Heavy Launch Vehicle Overview
 

Merlin 1D+ & Propellant Densification

Using improved manufacturing techniques and materials, the Merlin 1D engine was developed with a great margin in operational conditions and a high degree of durability which would enable the engine to operate at higher thrust levels, pressures and temperatures than originally envisioned. In a 2013 press briefing, Elon Musk stated that Merlin 1D could be operated at a sea level thrust of 734 Kilonewtons, representing about a 12% increase in thrust (other unconfirmed numbers that floated around indicated thrust increases up to 20%). Perhaps SpaceX was already looking toward Falcon Heavy when designing the Merlin 1D for operation at this increased thrust setting. 
 Running the engine at a greater propellant mass flow rate will lead to a higher chamber pressure and combustion temperature, increasing the overall stress on the engine. When flying on Falcon Heavy, this M1D+ engine would set up the proper initial thrust to weight ratio and reduce gravity losses in the early ascent phase.
Another technique to be employed by Falcon Heavy is propellant densification for an improved propellant mass fraction and a longer burn time with associated performance increase.
Elon Musk stated that propellant densification capability would be added to all SpaceX launch facilities and it is likely that all Falcon Heavy missions will rely on densification. Densifying propellants is possible through cooling – increasing the mass than can be loaded into the limited tank volume of the launcher. 
 NASA studies have shown that LOX densification can increase the oxidizer mass by 8 to 10% compared to boiling-point LOX at –183°C. Cooling LOX below its boiling point is possible through the use of a Nitrogen subcooler that employs a Liquid Nitrogen bath (either at boiling point or sub-cooled) through which the LOX lines are running to allow an exchange of heat. 
LOX temperatures of below –200°C are achievable, however, an economic consideration is necessary when choosing the desired LOX temperature. Operational launchers that employ sub-cooled LOX are Antares (in its original version, using LOX at –196°C) and Soyuz 2-1v (-192°C LOX). Using sub-cooling, the oxidizer mass held in the central core stage's tank of Falcon Heavy could be increased by ~24,000 Kilograms. 

Sub-cooling the fuel, Rocket Propellant 1, is also possible, although its high freezing temperature of approximately –37°C and changes in viscosity as a function of temperature represent limitations when sub-cooling the fuel. Through sub-cooling the RP-1 to –25° to –30°C, the first stage could take on ~6 metric tons of additional fuel which will not match up with the increase in LOX. This could be compensated by filling an unused portion in the RP-1 tank (if part of the design) or have the M1D+ engines operate less fuel-rich, leading to increased temperatures and raising demand on the regenerative cooling system of the engine. 
 Equipment for propellant densification including LOX subcoolers has been spotted at the SpaceX launch pad at Vandenberg Air Force Base in 2014 and the addition of this type of equipment at SLC-40 at CCAFS and LC-39 at KSC is likely planned or already in progress.

[Настоящий Искандер]

del