Author Topic: Blue Origin's BE-4 Engine  (Read 102263 times)

Offline Steven Pietrobon

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Blue Origin's BE-4 Engine
« on: 02/25/2016 10:14 PM »
I think its time this engine has its own thread. Here are some images from

https://www.blueorigin.com/be4
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Offline Steven Pietrobon

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Re: Blue Origin's BE-4 Engine
« Reply #1 on: 02/25/2016 10:17 PM »
Here is the fact sheet. Not much technical information, but sea level thrust is 2.45 MN (550 klbf). Propellants are liquid oxygen and liquid methane (liquified natural gas). Cycle is oxygen rich staged combustion.
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Offline Steven Pietrobon

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Re: Blue Origin's BE-4 Engine
« Reply #2 on: 02/26/2016 12:22 AM »
Images of the BE-4 configurations.
« Last Edit: 02/26/2016 12:23 AM by Steven Pietrobon »
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline Apollo100

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Re: Blue Origin's BE-4 Engine
« Reply #3 on: 02/26/2016 03:32 PM »
The relative sizes of the hardware in the pictures is a bit off from the 3D models. Looks like the main turbopump shown on the floor and in the test stand is the smaller 400K version. Not sure why they would test it in the horizontal orientation if it is vertical in the engine.

Offline ethan829

Re: Blue Origin's BE-4 Engine
« Reply #4 on: 02/26/2016 04:33 PM »
Tory Bruno just said on reddit that two BE-4s will cost less than a single RD-180. Obviously that's a ballpark estimate and could very well change, but it's nice to know the target prices are competitive.

https://www.reddit.com/r/ula/comments/47jsfy/new_be4_information_page_from_blue_origin/d0erahf
Quote
However, as a pair, BE4 or AR1 will offer around 30% more thrust than a single RD180. The pair will cost less than a single RD180 and with increased tank size, there will be fewer SRMs for the same mission.

Offline Prober

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Re: Blue Origin's BE-4 Engine
« Reply #5 on: 02/26/2016 04:45 PM »
Tory Bruno just said on reddit that two BE-4s will cost less than a single RD-180. Obviously that's a ballpark estimate and could very well change, but it's nice to know the target prices are competitive.

https://www.reddit.com/r/ula/comments/47jsfy/new_be4_information_page_from_blue_origin/d0erahf
Quote
However, as a pair, BE4 or AR1 will offer around 30% more thrust than a single RD180. The pair will cost less than a single RD180 and with increased tank size, there will be fewer SRMs for the same mission.


strange he has listed the AR1 in that comment.   The final papers must not be signed and the AR1 is the backup?

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Offline kch

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Re: Blue Origin's BE-4 Engine
« Reply #6 on: 02/26/2016 04:58 PM »
Tory Bruno just said on reddit that two BE-4s will cost less than a single RD-180. Obviously that's a ballpark estimate and could very well change, but it's nice to know the target prices are competitive.

https://www.reddit.com/r/ula/comments/47jsfy/new_be4_information_page_from_blue_origin/d0erahf
Quote
However, as a pair, BE4 or AR1 will offer around 30% more thrust than a single RD180. The pair will cost less than a single RD180 and with increased tank size, there will be fewer SRMs for the same mission.


strange he has listed the AR1 in that comment.   The final papers must not be signed and the AR1 is the backup?

Right!  :)

From the Blue Origin Update and Discussion Thread:


Tory Bruno has mentioned on reddit that Blue Origin agreed to ULA's target cost for BE-4, although no mention of any specific number.

https://www.reddit.com/r/ula/comments/43v33x/be4_forgings_assemble_full_engine_testing_later/czq86eb
Quote
BE4 is our primary path because it started first, is fully funded, and Blue has signed up to our target cost. AR1 is our back up because engines are complicated, risky, and BE4 will be the largest methane engine ever built (so there's technical risk). I plan to downselect after BE4's full scale static testing in about a year. That's when we'll know if the technology will work and can be on schedule.

Offline Damon Hill

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Re: Blue Origin's BE-4 Engine
« Reply #7 on: 03/02/2016 03:17 AM »
Where is the engine being built, and tested?  I doubt it's the Kent, WA facility because of the noise, though Kent has equipment in the back of the main building that suspiciously suggests an engine test facility.

--Damon

Offline jongoff

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Re: Blue Origin's BE-4 Engine
« Reply #8 on: 03/02/2016 03:34 AM »
Where is the engine being built, and tested?  I doubt it's the Kent, WA facility because of the noise, though Kent has equipment in the back of the main building that suspiciously suggests an engine test facility.

--Damon

The engine is probably being built in Kent, but the stand for BE-4 is in West Texas. There was a picture of the stand in one of these threads.

~Jon

Offline GreenShrike

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Re: Blue Origin's BE-4 Engine
« Reply #9 on: 03/09/2016 04:41 PM »
Ars Technica reports that the combustion chamber pressure of the BE-4 is 1950 psi.

Quote
Bezos explained his philosophy on how to build a successful reusable engine: Our strategy is we like to choose a medium-performing version of a high-performance architecture. Heres what that means: The Russian RD-180 engine is a high-performing version of a high performance architecture. It uses the best materials and pushes the performance envelope. It is the Ferrari of engines. But that comes with a cost. When it fires, the RD-180 engines produces extremely high chamber pressures of up to 3,700 psi. By comparison, the BE-4 engine produces a chamber pressure of 1,950 psi.

http://arstechnica.com/science/2016/03/behind-the-curtain-ars-goes-inside-blue-origins-secretive-rocket-factory/
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Offline baldusi

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Re: Blue Origin's BE-4 Engine
« Reply #10 on: 03/09/2016 05:39 PM »
Ars Technica reports that the combustion chamber pressure of the BE-4 is 1950 psi.

Quote
Bezos explained his philosophy on how to build a successful reusable engine: Our strategy is we like to choose a medium-performing version of a high-performance architecture. Heres what that means: The Russian RD-180 engine is a high-performing version of a high performance architecture. It uses the best materials and pushes the performance envelope. It is the Ferrari of engines. But that comes with a cost. When it fires, the RD-180 engines produces extremely high chamber pressures of up to 3,700 psi. By comparison, the BE-4 engine produces a chamber pressure of 1,950 psi.

http://arstechnica.com/science/2016/03/behind-the-curtain-ars-goes-inside-blue-origins-secretive-rocket-factory/
Yes, and the RD-180 is still rated for 10 missions. No wonder it is not even close to the RD-180 in performance.

Offline Ronsmytheiii

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Re: Blue Origin's BE-4 Engine
« Reply #11 on: 03/12/2016 12:43 PM »
Quote
CULBERSON COUNTY, Texas (Blue Origin PR) BE-4 testing is well underway at Blue Origin. To date, weve completed more than 170 staged-combustion tests including 51 starts on a single regeneratively cooled chamber and nozzle. The preburner performed flawlessly and the main injector consistently demonstrated performance at the high end of our predictions, giving us confidence that well get good specific impulse when we go to full-scale engine testing later this year.

Also includes news on more test stand construction:

Quote
One of the many benefits of a privately funded engine development is that we can make and implement decisions quickly. Building these two new test cells is a $10 million commitment, and we as a team made the decision to move forward in 10 minutes.

http://www.parabolicarc.com/2016/03/11/be4-engine-testing-update-jeff-bezos/
« Last Edit: 03/12/2016 12:44 PM by Ronsmytheiii »

Offline J-V

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Re: Blue Origin's BE-4 Engine
« Reply #12 on: 03/12/2016 07:24 PM »
FYI The article in Parabolicarc is essentially an email from the BO mailing list, sent few days ago. You can subscribe in https://www.blueorigin.com I subscribed several weeks ago and this was the first mail from Jeff so far. Sorry for not sending it here, but mobile...

Offline sanman

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Re: Blue Origin's BE-4 Engine
« Reply #13 on: 03/14/2016 01:30 AM »
Old press conference from Sept-2014



PS: that first pic Steve posted has such a beautiful blue flame - I'll bet it makes night launches look spectacular
« Last Edit: 03/14/2016 01:33 AM by sanman »

Offline Nilof

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Re: Blue Origin's BE-4 Engine
« Reply #14 on: 03/17/2016 12:59 PM »
...so now that we have the chamber pressure information available, we could start speculating about other numbers. Plugging it into MPA, assuming an Isp-optimized O/F ratio and assuming that the nozzle is optimized for maximum thrust at sea level (more likely it'll be optimized for a somewhat lower pressure since Vulcan stages late) , I get a theoretical ideal specific impulse of 327 s SL and 351 s vac.

MPA lite gives me a likely "as it turns out" specific impulse of 315 s SL and 339 s vac. This is where having the full version of the program would be nice to better approximate staged combustion efficiency and get an approximate T/W ratio. But either way, it seems to predict a somewhat lower specific impulse with the BE-4 than with the RD-180, and with a less dense fuel composition. Then again, SpaceX's Raptor development seems to suggest that Methane performs above their initial expectations, so it may be the case that the BE-4 performance will also be closer to its theoretical ideal.

Here's the full output from MPA: # Engine name: BE-4
# Thu 17. Mar 14:46:58 2016
#
#***************************************************************************************************
# Propellant Specification
#---------------------------------------------------------------------------------------------------
#    Component  Temp.          Mass          Mole
#                 [K]      fraction      fraction
#---------------------------------------------------------------------------------------------------
#       CH4(L)  111.6     0.2286613     0.3715842
#        O2(L)   90.2     0.7713387     0.6284158
#---------------------------------------------------------------------------------------------------
#              Total:     1.0000000     1.0000000
#---------------------------------------------------------------------------------------------------
#    Exploded formula:   (O)1.257 (C)0.372 (H)1.486
#                O/F:     3.3732812
#              O/F 0:     3.9892635 (stoichiometric)
#              alpha:     0.8455900 (oxidizer excess coefficient)
#---------------------------------------------------------------------------------------------------
#
# Table 1. Thermodynamic properties
#---------------------------------------------------------------------------------------------------
#          Parameter      Injector    Nozzle inl    Nozzle thr    Nozzle exi          Unit   
#---------------------------------------------------------------------------------------------------
            Pressure       13.4000       13.4000        7.7479        0.1013           MPa   
         Temperature     3633.4053     3633.4053     3449.6604     2120.8213             K   
            Enthalpy    -1584.7448    -1584.7448    -2320.7245    -6733.3422         kJ/kg   
             Entropy       11.9543       11.9543       11.9543       11.9543     kJ/(kgK)   
Specific heat (p=const)        6.4073        6.4073        6.2065        2.3677     kJ/(kgK)   
Specific heat (V=const)        5.4605        5.4605        5.3268        2.0007     kJ/(kgK)   
        Gas constant        0.3818        0.3818        0.3771        0.3559     kJ/(kgK)   
    Molecular weight       21.7772       21.7772       22.0482       23.3617                 
 Isentropic exponent        1.1344        1.1344        1.1315        1.1828                 
             Density        9.6596        9.6596        5.9559        0.1342         kg/m   
      Sonic velocity     1254.4618     1254.4618     1213.2454      944.8885           m/s   
            Velocity        0.0000        0.0000     1213.2454     3208.9242           m/s   
         Mach number        0.0000        0.0000        1.0000        3.3961                 
          Area ratio        0.0000        0.0000        1.0000       16.7747                 
           Mass flux        0.0000        0.0000     7225.9842      430.7661     kg/(ms)   
#---------------------------------------------------------------------------------------------------
#
#---------------------------------------------------------------------------------------------------
#
# Table 2. Fractions of the combustion products
#---------------------------------------------------------------------------------------------------
#            Species      Injector      Injector    Nozzle inl    Nozzle inl    Nozzle thr    Nozzle thr    Nozzle exi    Nozzle exi   
#                       mass fract    mole fract    mass fract    mole fract    mass fract    mole fract    mass fract    mole fract   
#---------------------------------------------------------------------------------------------------
                  CO     0.2310086     0.1796041     0.2310086     0.1796041     0.2202208     0.1733472     0.1561277     0.1302175   
                 CO2     0.2642280     0.1307480     0.2642280     0.1307480     0.2812219     0.1408886     0.3819814     0.2027683   
                COOH     0.0000486     0.0000235     0.0000486     0.0000235     0.0000281     0.0000138     0.0000000     0.0000000   
                   H     0.0008998     0.0194399     0.0008998     0.0194399     0.0007611     0.0166498     0.0000418     0.0009684   
                  H2     0.0074850     0.0808590     0.0074850     0.0808590     0.0070773     0.0774057     0.0065192     0.0755498   
                 H2O     0.4123624     0.4984720     0.4123624     0.4984720     0.4216903     0.5160903     0.4545258     0.5894158   
                H2O2     0.0000482     0.0000308     0.0000482     0.0000308     0.0000280     0.0000181     0.0000000     0.0000000   
     HCHO,formaldehy     0.0000011     0.0000008     0.0000011     0.0000008     0.0000006     0.0000004     0.0000000     0.0000000   
                 HCO     0.0000277     0.0000208     0.0000277     0.0000208     0.0000150     0.0000114     0.0000000     0.0000000   
               HCOOH     0.0000099     0.0000047     0.0000099     0.0000047     0.0000056     0.0000027     0.0000000     0.0000000   
                 HO2     0.0002153     0.0001421     0.0002153     0.0001421     0.0001292     0.0000863     0.0000000     0.0000000   
                   O     0.0060003     0.0081672     0.0060003     0.0081672     0.0045170     0.0062247     0.0000058     0.0000084   
                  O2     0.0282713     0.0192404     0.0282713     0.0192404     0.0232214     0.0160003     0.0000382     0.0000279   
                  O3     0.0000003     0.0000001     0.0000003     0.0000001     0.0000000     0.0000000     0.0000000     0.0000000   
                  OH     0.0493935     0.0632464     0.0493935     0.0632464     0.0410836     0.0532605     0.0007599     0.0010438   
#---------------------------------------------------------------------------------------------------
#
#---------------------------------------------------------------------------------------------------
#
# Table 3. Theoretical (ideal) performance
#---------------------------------------------------------------------------------------------------
#          Parameter     Sea level    Optimum ex        Vacuum          Unit   
#---------------------------------------------------------------------------------------------------
Characteristic velocity        0.0000     1854.4200        0.0000           m/s   
Effective exhaust velocity     3208.9200     3208.9200     3444.1400           m/s   
Specific impulse (by mass)     3208.9200     3208.9200     3444.1400        Ns/kg   
Specific impulse (by weight)      327.2200      327.2200      351.2100             s   
  Thrust coefficient        1.7304        1.7304        1.8573                 
#---------------------------------------------------------------------------------------------------
#
#---------------------------------------------------------------------------------------------------
#
# Table 4. Estimated delivered performance
#---------------------------------------------------------------------------------------------------
#          Parameter     Sea level    Optimum ex        Vacuum          Unit   
#---------------------------------------------------------------------------------------------------
Characteristic velocity        0.0000     1834.4100        0.0000           m/s   
Effective exhaust velocity     3092.1300     3092.1300     3327.3500           m/s   
Specific impulse (by mass)     3092.1300     3092.1300     3327.3500        Ns/kg   
Specific impulse (by weight)      315.3100      315.3100      339.3000             s   
  Thrust coefficient        1.6856        1.6856        1.8139                 
#---------------------------------------------------------------------------------------------------
#
#Ambient condition for optimum expansion:  H=0.00 km, p=1.000 atm
#
#
« Last Edit: 03/17/2016 01:08 PM by Nilof »
For a variable Isp spacecraft running at constant power and constant acceleration, the mass ratio is linear in delta-v.   Δv = ve0(MR-1). Or equivalently: Δv = vef PMF. Also, this is energy-optimal for a fixed delta-v and mass ratio.

Offline GreenShrike

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Re: Blue Origin's BE-4 Engine
« Reply #15 on: 03/17/2016 04:18 PM »
Yes, and the RD-180 is still rated for 10 missions. No wonder it is not even close to the RD-180 in performance.

...so now that we have the chamber pressure information available, we could start speculating about other numbers. Plugging it into MPA, assuming an Isp-optimized O/F ratio and assuming that the nozzle is optimized for maximum thrust at sea level (more likely it'll be optimized for a somewhat lower pressure since Vulcan stages late) , I get a theoretical ideal specific impulse of 327 s SL and 351 s vac.

MPA lite gives me a likely "as it turns out" specific impulse of 315 s SL and 339 s vac. This is where having the full version of the program would be nice to better approximate staged combustion efficiency and get an approximate T/W ratio. But either way, it seems to predict a somewhat lower specific impulse with the BE-4 than with the RD-180, and with a less dense fuel composition.

The ISP of the RD-180 is around 312s/338s, according to SpaceLaunchReport, which is pretty much what you calculate for the BE-4. From baldusi's comments -- and what I understand about chamber pressure versus ISP -- I was expecting the BE-4 to be clearly under the RD-180's numbers.

Is the BE-4's supposed lower performance due to the lower density of methane versus RP-1?
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Offline baldusi

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Re: Blue Origin's BE-4 Engine
« Reply #16 on: 03/17/2016 06:46 PM »
Methane usually has a 10s to 15s isp advantage wrt RP-1 with everything else being equal. RD-180 not only has amazing isp, it also has 79:1 T/W. Since propulsion is usually 35% to 50% of a first stage dry mass, that also counts a lot. Then you have the lower density of CH4. So anything using the BE-4 won't be as efficient as the RD-180. Oversizing overcomes the inefficiencies.

Offline Nilof

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Re: Blue Origin's BE-4 Engine
« Reply #17 on: 03/17/2016 07:41 PM »
Main reason why predicted isp for BE-4 is lower than predicted isp for RD-180 is the lower chamber pressure. For a vacuum optimized engine methalox will always give that 10-15 sec Isp advantage since you can have any expansion ratio you want. At sea level the chamber pressure affects Isp much more more than propellant choice because it limits the expansion ratio you can have.
« Last Edit: 03/17/2016 07:42 PM by Nilof »
For a variable Isp spacecraft running at constant power and constant acceleration, the mass ratio is linear in delta-v.   Δv = ve0(MR-1). Or equivalently: Δv = vef PMF. Also, this is energy-optimal for a fixed delta-v and mass ratio.

Offline STS-200

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Re: Blue Origin's BE-4 Engine
« Reply #18 on: 03/18/2016 10:56 AM »
I would be amazed if the engine they end up producing used such a low expansion ratio as 16.7.

For a booster engine, the criteria is usually closer to maximising efficiency over the flight while avoiding flow separation at sea level, rather than absolute maximum thrust. I would expect an ER of more like 25-35, depending on what they are optimising it for.

At ER=25, I would expect to see more like SL~310s, Vacuum~345s in a "real world" engine.
In absolute Isp numbers, I suspect they'll exceed the RD-180 on average. Whether they beat it in T/W or in other measure remains to be seen.

They appear to be trading the inherent efficiency of Methane as a fuel for a lower chamber pressure, which makes for a "less stressed" engine; probably easier to build and allowing for longer component or cycle life - they state they're building it to be re-usable.

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Offline TrevorMonty

Re: Blue Origin's BE-4 Engine
« Reply #19 on: 03/18/2016 11:31 AM »
The BE4 should have high T/W as it uses additive manufacturing which helps to keep weight down.

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