SpaceX семейство метановых двигателей Raptor

[Искандер]

Apollo13 пишет:

alicia hamblin ‏ @leechy3 14h14 hours ago

I heard new alloys...I'm interested! What types of alloys are you currently using on the rocket?

 https://twitter.com/elonmusk/status/1008385171744174080

Elon Musk ‏Verified account @elonmusk

Replying to @leechy3 @kausthav_ray @SpaceX

SX 300 & soon SX 500. Kind of a modern version of Inconel superalloys. High strength at temperature, extreme oxidation resistance. Needed for ~800 atmosphere, hot, oxygen-rich turbopump on Raptor rocket engine.

И каким образом они собираются обеспечить 1000-кратность с такими параметрами??? 8-. Петарда похлеще семейства РД-170.

Кстати, кто нибудь в курсе, газ-газ уменьшает проблемы с акустикой? 

[Старый]

Искандер пишет: 
Кстати, кто нибудь в курсе, газ-газ уменьшает проблемы с акустикой?

В камере сгорания уменьшает. Но переносит их в газогенераторы.

[Apollo13]

Chris B - NSF‏ @NASASpaceflight 23 Dec 2018

While we have you, Elon.... How well is Raptor performing during test stand firings at McGregor? On track to support your Super Heavy/Starship schedule?

Elon Musk‏Verified account @elonmusk 23 Dec 2018

Replying to @NASASpaceflight @_Synders and 6 others

Yes. Radically redesigned Raptor ready to fire next month.

[Apollo13]

Elon Musk‏Verified account @elonmusk 23 Dec 2018

Replying to @Erdayastronaut @NASASpaceflight and 6 others

Yes, full flow, gas-gas, staged combustion. Will take us time to work up to 300 bar. That is a mad level.

[Apollo13]

Elon Musk‏Verified account @elonmusk 23 Dec 2018

Replying to @Robotbeat @Jon128123 and 8 others

SpaceX metallurgy team developed SX500 superalloy for 12000 psi, hot oxygen-rich gas. It was hard. Almost any metal turns into a flare in those conditions.

Elon Musk‏Verified account @elonmusk 23 Dec 2018

Replying to @elonmusk @Robotbeat and 9 others

Our superalloy foundry is now almost fully operational. This allows rapid iteration on Raptor.

[Apollo13]

Thomas Burghardt‏ @TGMetsFan98 31 Dec 2018

Well, well, well, what do we have here... Via NSF user bocachicagal: https://forum.nasaspaceflight.com/index.php?topic=47022.msg1894673#msg1894673 ...

[axxenm]

Это явно не экспериментальная версия Старшипа, как некоторыми заявляется.так как с его конструкцией нет ничего общего, кроме может быть диаметра.
Скорее "прыгающий" стенд для проверки работы Раптора 
Отсюда столь небрежный до смешного вид и сборка в чистом поле.

Молодцы.
Очень интересно насколько прототипы Раптора на этом "прыгающем".стенде.будут близки к целевым параметрам : 250(300) атм , 180тс тяги УМ, схема газ-газ.

[Seerndv]

SpaceX metallurgy team developed SX500 superalloy for 12000 psi, hot oxygen-rich gas.

12000 psi  = 817 атм

Типа, запас есть.  :|

[axxenm]

Seerndv пишет:

SpaceX metallurgy team developed SX500 superalloy for 12000 psi, hot oxygen-rich gas.

12000 psi = 817 атм

Типа, запас есть.  :|

Означают ли такие заявления Маска то , что они снова в начале долгого этапа по достижению заранее заявленных параметров?
Может разобьют Раптор на 2 линейки -  движки с рекордными, давно заявленными параметрами ,и то ,что получается на данный момент?

[Seerndv]

axxenm пишет:

Seerndv пишет:

SpaceX metallurgy team developed SX500 superalloy for 12000 psi, hot oxygen-rich gas.

12000 psi = 817 атм

Типа, запас есть.  :|  

Означают ли такие заявления Маска то , что они снова в начале долгого этапа по достижению заранее заявленных параметров?
Может разобьют Раптор на 2 линейки - движки с рекордными, давно заявленными параметрами ,и то ,что получается на данный момент?

- а почему бы нет?
И да, чой то не видно генератора сладкого газа у Маска.
Опять не "газ-газ", а "кислый" ГГ + газификация метана? Опять же, будь я на его месте внимательно бы следил за Безосом, вплоть до промышленного шпионажа и перекупки разработчиков. Хотя, возможно всё происходит наоборот 

[Apollo13]

https://www.reddit.com/r/spacex/comments/ab9w94/lower_bfh_section_with_raptor_nozzles_showing_via/ecywfhq/

//[–]Senno_Ecto_Gammat r/SpaceXLounge Moderator 1897 points 1 day ago*x5x5x2 

In a rocket nozzle, the pressure of the exhaust drops as it flows fr om the throat to the nozzle exit. There is high pressure in the chamber to push everything out and then by the time it gets to the exit the pressure is low.
If the pressure of the exhaust at the exit is the same as the ambient pressure, the exhaust coming out of the nozzle will form an orderly, compact, and narrow plume as it moves away fr om the rocket, because the pressure of the exhaust gases will balance exactly with the pressure of the ambient environment. This balance is called the design condition of the rocket engine and it is the most efficient operating condition for the nozzle. 

 shows a Soyuz rocket with its engines firing near the design condition - the exhaust plume under each engine is a compact column of flame travelling straight down and away fr om the rocket.
If the pressure inside the exhaust plume is greater than the ambient pressure, the plume will expand rapidly in all directions after it exits the nozzle until it reaches an equilibrium pressure with the environment. This condition is called underexpansion or underexpanded flow, because it is created by a nozzle expansion ratio that is too low. Underexpansion can be corrected by re-engineering the engine with a larger nozzle exit to increase the expansion ratio, lowering the exhaust pressure at the exit to more closely match the ambient pressure. An engine that is underexpanded sacrifices performance - further expansion inside the nozzle to reduce exhaust pressure increases the velocity of the exhaust and thus the thrust and efficiency of the engine.
If the exit pressure is below ambient pressure, the exhaust plume will be pressed in on itself by the imbalance. Instead of leaving the nozzle and forming a smooth column, the exhaust will collapse inward and bounce against itself, forming a series of standing shockwaves inside the plume called shock diamonds or sometimes mach diamonds. These shockwaves give the plume a knotted or braided appearance and are caused by overexpansion of the flow inside the nozzle. The remedy is to engineer a smaller nozzle, reducing expansion ratio and thus increasing the exit pressure to more closely align with the ambient pressure. An overexpanded plume with the characteristic braided appearance can be seen in 

.
In all of the cases so far, the exhaust flow follows the contours of the nozzle smoothly fr om the combustion chamber to the exit, and only separates fr om the nozzle as it exits. However, in a special case of overexpansion, when the exhaust pressure at the nozzle exit is much lower than the ambient pressure, the air from the environment outside the nozzle can impinge on the flow exiting the nozzle and can creep up the inside of the nozzle wall, coming between the wall and the exhaust flow and causing the flow to separate from the nozzle well before the nozzle exit. At the point wh ere the flow separates from the nozzle, a powerful shock wave is formed which can damage or destroy the nozzle. In addition to the danger, this flow separation drastically reduces the efficiency of the engine. For these reasons, no rocket engines are designed to operate in a state of flow separation. 

Some minor and transient flow separation is common during the ignition sequence, as shown in 

 of the space shuttle main engines' ignition. The shockwave is visible as a jagged and broken line inside the engine nozzles, with the nozzle on the left side of the image experiencing greater flow separation due to staggered timing of the ignition of each engine.
The characteristics of underexpansion, overexpansion, and flow separation have several consequences that must be considered. First, the risk associated with flow separation is one of the things that forms a lim it ability of a rocket to throttle down. Thrust in a rocket engine is reduced by lowering the pressure inside the combustion chamber. Because the drop in pressure between the chamber and the nozzle exit is determined wholly by the nozzle geometry, a reduction in the chamber pressure of a given engine will always correspond with a reduction in exit pressure. While the combustion chamber might be capable of operating at a very low pressure, the downstream effect in the nozzle must be considered, and the threat of flow separation limits how low the pressure at the nozzle can go.
Second, flow through a rocket engine nozzle with a design condition for sea level flight will become increasingly underexpanded as the rocket flies toward space and the ambient pressure falls. If the ambient pressure when the rocket is on the ground matches the nozzle exit pressure, then the ambient pressure at altitude wh ere the air is thinner will be much lower than the nozzle exit pressure, because the nozzle exit pressure does not change in flight. This change from design condition to severe underexpansion is visible during many launches, and very visible on F9 launches. If you watch any launch when the rocket is at sea level, it will at launch produce a narrow and compact column of flame. As the rocket goes up into thin air, the exhaust plume begins to expand outward after it leaves the nozzle, becoming wider and more diffuse - the hallmarks of underexpansion. The expansion of the plume at altitude represents a lost opportunity for greater thrust and efficiency through the use of a much larger expansion ratio in the nozzle to reduce exit pressure.
Third, an engine designed with a very large expansion ratio for use in a vacuum will experience destructive flow separation if operated at sea level. The very thing that makes it ideal for vacuum use - a highly expanded flow and thus very low exit pressure - will lead to collapse of the plume, flow separation, and destruction of the nozzle in the high pressure air on the ground.
Engines designed for use at low altitudes are less efficient at higher altitudes, and engines designed for use at high altitude or in a vacuum cannot be used at low altitude. This is one reason among many why rockets are designed to operate in stages, with the lower stage, often called the boost stage, or simply the booster, using engines designed for operation in the dense atmosphere, and an upper stage using engines designed for operation in the wispy upper atmosphere and the vacuum of space. The boost stage engines operate at a lower expansion ratio, and are used to lift the upper stage out of the dense atmosphere and to high altitude. Once this is achieved, the boost stage is separated and the upper stage continues onward toward orbit using an engine with a high expansion ratio. This type of engine is often called a vacuum engine. The optimum nozzle design for an engine operating in a vacuum is one with an infinite expansion ratio which can bring the exhaust pressure down to zero, matching the ambient pressure. Any smaller and the nozzle suffers from underexpansion. Of course an infinitely large nozzle is not possible, so vacuum engines have to settle for nozzles of a large, but finite size. Typically the nozzle on a vacuum engine is several times the diameter of an equivalent sea level engine.
The Rutherford engine is used on both the boost stage and upper stage of the Electron rocket. As shown 

 the nozzle on the sea-level engine is so compact that the entire engine can easily be held by a single person. Nine Rutherford engines can fit on the base of the 1.2 meter-wide rocket. Despite an identically-sized combustion chamber and throat, 

 and only a single one can fit on the upper stage. And even this is a compromise; a larger nozzle would be better, but would not fit in the adapter between the two stages of the rocket.
The allure of an engine that has the efficiency of a high expansion ratio combined with the ability to operate at sea level has led to several proposals for what are called altitude compensating nozzles. The most conceptually straightforward is the expandable nozzle - a sea-level nozzle with a large extension that can be pulled up and out of the flow for operation at sea level and then extended into the flow for vacuum use. The concept is shown 

. No expandable nozzles have been put into operation for altitude compensation purposes, but some vacuum engines such as the RL-10b-2 use an expandable nozzle to save room inside the rocket before stage separation. The nozzle extension tucks up and away and is only deployed just before the engine ignites at altitude.
Dual-bell nozzles are designed with an abrupt change in the nozzle curvature around the place in the nozzle wh ere the expansion ratio is appropriate for sea level operation. The sharp edge at this place in the nozzle induces predictable and controlled flow separation in sea-level flight. As the rocket climbs, the changing ambient pressure allows the exhaust flow to expand further through the nozzle until the full expansion ratio is achieved. The dual-bell concept is illustrated 

.
You can see that characteristic kink in the image at the top of the thread. 

 showing the kink in the nozzle at the point wh ere they want the flow to separate.

Мне показался интересным этот комментарий.

Кто-то знает как по-русски называется "altitude-compensating dual-bell nozzle"? Речь не о дословном переводе, а об устоявшемся термине. Также интересно где оно ранее применялось.

[Apollo13]

Если диаметр BFH равен 9 м, то диаметр в месте где ступенька 0,8 м, на срезе сопла 1,3 м. Можно сравнить с этим. ИМХО это мини-Рапторы.

[Старый]

Apollo13 пишет:
Кто-то знает как по-русски называется "altitude-compensating dual-bell nozzle"?

Сопло с раздвижным насадком для компенсации недорасширения на высоте. У нас такое предлагали на НК-33.

[opinion]

Старый пишет:

Apollo13 пишет:
Кто-то знает как по-русски называется "altitude-compensating dual-bell nozzle"?

Сопло с раздвижным насадком для компенсации недорасширения на высоте. У нас такое предлагали на НК-33.

Но сопло на фотографии и в цитате, приведенной Apollo13 не раздвижное. В месте, отмеченном зелеными стрелками есть перелом в профиле сопла. В этом месте поток контролируемо отрывается от сопла при работе на уровне земли или дросселировании.

[Apollo13]

Старый пишет:

Apollo13 пишет:
Кто-то знает как по-русски называется "altitude-compensating dual-bell nozzle"?

Сопло с раздвижным насадком для компенсации недорасширения на высоте. У нас такое предлагали на НК-33.

Он не раздвижной. 

The sharp edge at this place in the nozzle induces predictable and controlled flow separation in sea-level flight.

[Дмитрий В.]

Apollo13 пишет:
https://www.reddit.com/r/spacex/comments/ab9w94/lower_bfh_section_with_raptor_nozzles_showing_via/ecywfhq/

][–] Senno_Ecto_Gammat r/SpaceXLounge Moderator 1897 points 1 day ago* x5 x5 x2

In a rocket nozzle, the pressure of the exhaust drops as it flows fr om the throat to the nozzle exit. There is high pressure in the chamber to push everything out and then by the time it gets to the exit the pressure is low.
If the pressure of the exhaust at the exit is the same as the ambient pressure, the exhaust coming out of the nozzle will form an orderly, compact, and narrow plume as it moves away fr om the rocket, because the pressure of the exhaust gases will balance exactly with the pressure of the ambient environment. This balance is called the design condition of the rocket engine and it is the most efficient operating condition for the nozzle.

shows a Soyuz rocket with its engines firing near the design condition - the exhaust plume under each engine is a compact column of flame travelling straight down and away fr om the rocket.
If the pressure inside the exhaust plume is greater than the ambient pressure, the plume will expand rapidly in all directions after it exits the nozzle until it reaches an equilibrium pressure with the environment. This condition is called underexpansion or underexpanded flow, because it is created by a nozzle expansion ratio that is too low. Underexpansion can be corrected by re-engineering the engine with a larger nozzle exit to increase the expansion ratio, lowering the exhaust pressure at the exit to more closely match the ambient pressure. An engine that is underexpanded sacrifices performance - further expansion inside the nozzle to reduce exhaust pressure increases the velocity of the exhaust and thus the thrust and efficiency of the engine.
If the exit pressure is below ambient pressure, the exhaust plume will be pressed in on itself by the imbalance. Instead of leaving the nozzle and forming a smooth column, the exhaust will collapse inward and bounce against itself, forming a series of standing shockwaves inside the plume called shock diamonds or sometimes mach diamonds. These shockwaves give the plume a knotted or braided appearance and are caused by overexpansion of the flow inside the nozzle. The remedy is to engineer a smaller nozzle, reducing expansion ratio and thus increasing the exit pressure to more closely align with the ambient pressure. An overexpanded plume with the characteristic braided appearance can be seen in

.
In all of the cases so far, the exhaust flow follows the contours of the nozzle smoothly fr om the combustion chamber to the exit, and only separates fr om the nozzle as it exits. However, in a special case of overexpansion, when the exhaust pressure at the nozzle exit is much lower than the ambient pressure, the air from the environment outside the nozzle can impinge on the flow exiting the nozzle and can creep up the inside of the nozzle wall, coming between the wall and the exhaust flow and causing the flow to separate from the nozzle well before the nozzle exit. At the point wh ere the flow separates from the nozzle, a powerful shock wave is formed which can damage or destroy the nozzle. In addition to the danger, this flow separation drastically reduces the efficiency of the engine. For these reasons, no rocket engines are designed to operate in a state of flow separation.

Some minor and transient flow separation is common during the ignition sequence, as shown in

of the space shuttle main engines' ignition. The shockwave is visible as a jagged and broken line inside the engine nozzles, with the nozzle on the left side of the image experiencing greater flow separation due to staggered timing of the ignition of each engine.
The characteristics of underexpansion, overexpansion, and flow separation have several consequences that must be considered. First, the risk associated with flow separation is one of the things that forms a lim it ability of a rocket to throttle down. Thrust in a rocket engine is reduced by lowering the pressure inside the combustion chamber. Because the drop in pressure between the chamber and the nozzle exit is determined wholly by the nozzle geometry, a reduction in the chamber pressure of a given engine will always correspond with a reduction in exit pressure. While the combustion chamber might be capable of operating at a very low pressure, the downstream effect in the nozzle must be considered, and the threat of flow separation limits how low the pressure at the nozzle can go.
Second, flow through a rocket engine nozzle with a design condition for sea level flight will become increasingly underexpanded as the rocket flies toward space and the ambient pressure falls. If the ambient pressure when the rocket is on the ground matches the nozzle exit pressure, then the ambient pressure at altitude wh ere the air is thinner will be much lower than the nozzle exit pressure, because the nozzle exit pressure does not change in flight. This change from design condition to severe underexpansion is visible during many launches, and very visible on F9 launches. If you watch any launch when the rocket is at sea level, it will at launch produce a narrow and compact column of flame. As the rocket goes up into thin air, the exhaust plume begins to expand outward after it leaves the nozzle, becoming wider and more diffuse - the hallmarks of underexpansion. The expansion of the plume at altitude represents a lost opportunity for greater thrust and efficiency through the use of a much larger expansion ratio in the nozzle to reduce exit pressure.
Third, an engine designed with a very large expansion ratio for use in a vacuum will experience destructive flow separation if operated at sea level. The very thing that makes it ideal for vacuum use - a highly expanded flow and thus very low exit pressure - will lead to collapse of the plume, flow separation, and destruction of the nozzle in the high pressure air on the ground.
Engines designed for use at low altitudes are less efficient at higher altitudes, and engines designed for use at high altitude or in a vacuum cannot be used at low altitude. This is one reason among many why rockets are designed to operate in stages, with the lower stage, often called the boost stage, or simply the booster, using engines designed for operation in the dense atmosphere, and an upper stage using engines designed for operation in the wispy upper atmosphere and the vacuum of space. The boost stage engines operate at a lower expansion ratio, and are used to lift the upper stage out of the dense atmosphere and to high altitude. Once this is achieved, the boost stage is separated and the upper stage continues onward toward orbit using an engine with a high expansion ratio. This type of engine is often called a vacuum engine. The optimum nozzle design for an engine operating in a vacuum is one with an infinite expansion ratio which can bring the exhaust pressure down to zero, matching the ambient pressure. Any smaller and the nozzle suffers from underexpansion. Of course an infinitely large nozzle is not possible, so vacuum engines have to settle for nozzles of a large, but finite size. Typically the nozzle on a vacuum engine is several times the diameter of an equivalent sea level engine.
The Rutherford engine is used on both the boost stage and upper stage of the Electron rocket. As shown

the nozzle on the sea-level engine is so compact that the entire engine can easily be held by a single person. Nine Rutherford engines can fit on the base of the 1.2 meter-wide rocket. Despite an identically-sized combustion chamber and throat,

and only a single one can fit on the upper stage. And even this is a compromise; a larger nozzle would be better, but would not fit in the adapter between the two stages of the rocket.
The allure of an engine that has the efficiency of a high expansion ratio combined with the ability to operate at sea level has led to several proposals for what are called altitude compensating nozzles. The most conceptually straightforward is the expandable nozzle - a sea-level nozzle with a large extension that can be pulled up and out of the flow for operation at sea level and then extended into the flow for vacuum use. The concept is shown

. No expandable nozzles have been put into operation for altitude compensation purposes, but some vacuum engines such as the RL-10b-2 use an expandable nozzle to save room inside the rocket before stage separation. The nozzle extension tucks up and away and is only deployed just before the engine ignites at altitude.
 Dual-bell nozzles are designed with an abrupt change in the nozzle curvature around the place in the nozzle wh ere the expansion ratio is appropriate for sea level operation. The sharp edge at this place in the nozzle induces predictable and controlled flow separation in sea-level flight. As the rocket climbs, the changing ambient pressure allows the exhaust flow to expand further through the nozzle until the full expansion ratio is achieved. The dual-bell concept is illustrated

.
You can see that characteristic kink in the image at the top of the thread.

showing the kink in the nozzle at the point wh ere they want the flow to separate.

Мне показался интересным этот комментарий.

Кто-то знает как по-русски называется "altitude-compensating dual-bell nozzle"? Речь не о дословном переводе, а об устоявшемся термине. Также интересно где оно ранее применялось.

Сопло с изломом образующей. Рассматривалось для выдвижных насадков (для сокращения длины). В частности, в вариантах 14Д12

[Apollo13]

Дмитрий В., спасибо. А реально такое нигде не применялось (без раздвижных насадков)?

[Сергей]

Apollo13 пишет:


Если диаметр BFH равен 9 м, то диаметр в месте где ступенька 0,8 м, на срезе сопла 1,3 м. Можно сравнить с этим . ИМХО это мини-Рапторы.

Действительно, похоже к прототипу Раптора добавлен кусок сверхзвукового профиля Раптора 35. Излом контура не велик, и как высотное сопло прототипа Раптора обеспечит безотрывное течение на высоте. Формально при снижении и посадке, и уменьшении высоты, данного излома контура не хватает для надежного отрыва выхлопа от стенок профиля Раптора 35. Однако при дросселировании скачком давления в КС при некотором давлении установится безотрывное течение газа только по соплу прототипа. Главный вопрос - устойчивость спускаемого аппарата на переходном режиме. Несимметричные отрывы газа от стенок сопла дают большие возмущающие моменты. Поэтому можно предположить, что особо высоко лететь не придется, как и посадка может быть жесткой.

[S.Chaban]

А возможно такое сопло испытать / отработать на стенде? или только на прототипе в полете?

Маск не зря сказал что полетный софт будут писать по-новому. Все время не понимал в чем с точки зрения полета настолько большая разница межды мерлином и раптором. 

[Salo]

Сопло с формой двойного колокола.

Патент МИЦУБИСИ ХЕВИ ИНДАСТРИЗ:
http://www.findpatent.ru/patent/238/2383769.html


Патент ВОЛЬВО АЭРО КОРПОРЭЙШН:
http://www.freepatent.ru/patents/2156875


Патент Центра Келдыша:
https://edrid.ru/rid/216.013.5013.html