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SpaceX's New Combustion Technologies
An anonymous reader shares this story that takes a look at some of the advances SpaceX is working on. "Getting a small group of human beings to Mars and back is no easy task, we learned at the recent GPU Technology Conference in San Jose hosted graphics chip and accelerator maker Nvidia. One of the problems with such a mission is that you need a very large and efficient rocket engine to get the amount of material into orbit for the mission, explained Adam Lichtl, who is director of research at SpaceX and who with a team of a few dozen programmers is try to crack the particularly difficult task of better simulating the combustion inside of a rocket engine. You need a large engine to shorten the trip to Mars, too....Not only do you need a lot of stuff to get to Mars and sustain a colony there, but you also need a way to generate fuel on Mars to come back to Earth. All of these factors affect the design of the rocket engine....As if these were not problems enough, there is another really big issue. The computational fluid dynamics, or CFD, software that is used to simulate the movement of fluids and gases and their ignition inside of all kinds of engines is particularly bad at assisting in rocket engine design. 'Methane is a fairly simple hydrocarbon that is perfectly good as a fuel,' Lichtl said. 'The challenge here is to design an engine that works efficiently with such a compound. But rocket engine CFD is hard. Really hard.'"
rocket science?
They think what they're doing is "hard"? What the hell do they know? I once had to scale a Ruby on Rails web app so it'd handle more than 8 requests per second. Let me tell you, that makes fluid dynamics and rocket engines and trips to Mars look easy-peasy!
Rocket science is soooooo hard!
The shepherds did so well protecting the flock that the sheep no longer believed that wolves existed.
It's time to stop jetting around the solar system on chemical rockets. Designers and funding should be directed towards lofting and running multi-megawatt reactors. They would be used to power multiple ION engines and once at the destination, provide power.
When Fascism comes to America, it will call itself Anti-Fascism, and tell you to give up your guns.
I can't even read the damn summary with its lacks of punctuation and basically disorganized format.
Worst summary ever. I'm glad the editors are doing their jobs (or not).
This is the first article I've seen that explains well how GPUs can/are being used for practical applications along with what can be achieved and some of the issues. Well worth the read even if you're not into this stuff.
I'm sure that there is a significant cost in developing this new approach to CFD (as well as pushing the envelope on GPU operation) but the result is going to be usable for different applications. TFA says there's irony in what SpaceX is doing here as it has applications with automotive Internal combustion engines but I see that as SpaceX/Musk having a secondary revenue stream for this work that doesn't mean he's helping out his direct competitors.
Along with that, they are driving the development of high speed inter GPU communications which I'm sure has value as well.
All this means is that Musk returns to his home planet, not only is the trip going to be fully funded, but he's going to have some money to throw around when he gets there.
myke
Mimetics Inc. Twitter
It's kind of the nature of research that you have to do research. Plus, if you think its hard to design rockets and "rolling your own" CFD models, just imagine how it was when you didn't have the computing power to go beyond the rudiments.
Those troglodytes designing say, the F1 might have had a bit harder of a time designing with limited knowledge and experience than now when can try rolling out likely designs based on good CFD models. Channeled explosions are not terribly forgiving of bad design in that way.
Rather, Spacex is able to make better rockets, less expensively, by using extensive CFD, modeling using models they developed. This will allow for optimization of designs, and reduce reliance on the old process dreaming up a design, building and test firing it, and if it didn't explode, analyze the parts for incremental improvements.
And rather than whine about how hard it is, maybe we should marvel at just how damn cool it is to have modern computing power and new flow and design models to work with to make better rockets. Too freaking cool!
The shepherds did so well protecting the flock that the sheep no longer believed that wolves existed.
Umm, rocket science is...rocket science?
Combustion CFD is a very difficult area. The problem is that there are so many interlinked phenomena all requiring special modeling methods that one really isn't quite certain of the accuracy of the result unless they can compare it to a physical model test, which is what is frequently done. Simply getting the correct boundary conditions can be very challenging. Failing to apply appropriate modeling and boundary situations leads to a garbage in/garbage out situation, but the numerical solution may look plausibly correct.
CFD is not use exclusively in design work except for very basic cases where the modeling accuracy is well understood. However, CFD for more complicated situations is still useful as it may illustrate behaviors and trends in performance in situations where physical observations are difficult (like in a rocket nozzle). The CFD results can be used to guide and interpret the results of physical testing.
Understanding CFD really requires PhDs who understand fluid dynamics as well as the limitations of the numerical models used. This is true in many industries, not just rocket surgery.
Left MS Windows for Linux Mint and never looked back!
Vote for Bernie in 2016!
Reading this made me appreciate what geniuses Goddard and Von Braun were - they didn't have all these fancy schmancy computers to simulate anything.
They built stuff, tested, gathered data and went back to the drawing board. Maybe these guys should build a prototype of what they think will work and go from there. At the very least, they'd get some real life data to work with.
Problems with injector design and combustion instability go back to to the Germans and the V2. They may have even been a problem for Goddard. The V2 engine is really a bunch of small combustion chambers at the top feeding into the main engine bell. I believe this was done, at least in part, to reduce the problems with combustion instability.
A much better and more efficient way to accurately simulate this process can really offer a lot in many areas, not just rocket engines.
Isn't the combustion chaotic?
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
Last year the National Research Council and National Academy of Science released a damming report on the prospects of the USA or any other country/society on Earth to mount a human space mission to the Moon or Mars. The verdict, 50 years at least and likely 150 years needed. Why? The humans/economy/society/education-training system/infrastructure/GDP do not currently exist and will not, until very likely 150-years from now.
As a matter of economic pragmatism, all current efforts, even writing code, will fail, so it is better to kill-off all national/state Federal departments engaged in the continuing failures that will persist until the humans/economy/society/education-training system/infrastructure/GDP exist and are capable to support such missions to the Moon or Mars. Using the savings from the Federal/State divesture and re-assinging the monies into banking/economy/education/finance/society would be better spend in order to build the national economy/society/education-training system/infrastructure/GDP in anticipation that in the future the humans not yet born will be able to use and figure out a solution.
Problem: the dynamic range of interest is high
both in time and space
A normal sim would handle this with LOTS of grid points and time steps.
Computers can't do this. (Not enough zeros.)
So they make the gird (and time scales?) variable and concentrate the mips where interesting stuff is happening.
I wonder what figure of merit they use to pick what will be interesting?
Maybe a fixed amount of energy or mass, or change gradient in each grid point.
Likely a combination of all this and more.
They don't seem to say.
I guess a good test to see if it works is to try slightly different merit functions and see if they get the same answer.
Or sim the engine with lots of test points as part of the design and see if the sim matches the real engine with visability.
Again, likely a combination of both.
It's kind of neat to think that upstart commercial space is causing traditional aerospace to step up it's game.
I wonder if this is the case, or if the trad stuff is just kept under wraps?
Nope. Unpowered flight already existed by the time the Wright brothers headed to Kitty Hawk, and powered flight was right on the edge of possibility. The drives you propose, aren't. The problem is, you don't grasp that fundamental difference and thus assume that people who aren't as egregiously ignorant as you are the ones in the wrong.
True. But those solutions must fall within the bounds of physics and chemistry - and nuclear reactors and ion engines, for the reasons I outlined, don't. Absent new physics, they never will.
Only to someone who doesn't grasp physics in general as well as the mathematics behind orbital mechanics. Absent new physics, all vehicles in space are going to spend far more time coasting than under power.
It may be worth waiting for technology like the EM drive or Nasa warp drive theory to pan out before we attempt a two way trip to Mars.
(Closer than you think!? http://emdrive.com/.)
A realistic version of this trip might look like could be: Use combustion to lift the project into Earth orbit then use an EM drive tech for the trek to Mars orbit and vice versa.
Cause humping a few hundred thousand square feet of fossil fuels around the galaxy would suck.
Go to Mars. *Stay there*. Don't return the Presbyterian astronauts back home to Ohio. Keep lobbing supplies at the colonists until they can sustain themselves. Why on earth do we keep trying to re-enact the Apollo fiasco? Colonize, or don't go. Plenty of older folk such as myself who would be glad of a few years of low G before we die while we build up the place for later arrivals. Dying there? The horror! Um, of course you'd die if you stay on Earth anyway. Dying on Mars would be more scenic, and your knees wouldn't hurt when you stand up.
Of course, Mars won't pay for itself as far as Earth is concerned, the way orbiting terraria and factories would. Less room, less opportunity, and yet another gravity trap on any planet. Mars is a place to colonize. It can't produce wealth for the old country. And colonies don't care about the old world much, so we're building a suburb that will home-rule faster than a town next door to a impoverished city.
Well, limited vision, but at least we'd have two baskets to put our eggs in.
"Getting a small group of human beings to Mars and back is no easy task, we learned at the recent GPU Technology Conference in San Jose hosted graphics chip and accelerator maker Nvidia.
It hardly gets spammier than that, congrats.
This guy walks into SpaceX.
Elon Musk says "You here for the interview?"
"Naw... just here to put in the Brawndo fountain."
E
just make sure you have a huge chem rocket engine firing at the same time...and you can leave orbit using an ion engine, a steam engine, or a bunch of hamsters.
My God can beat up your God. Just kidding...don't take offense. I know there's no God.
Was ULA making any investment in propulsion technology? Well they started using the Russian RD-180 in 2000 and didn't start looking for a replacement until 2014. This was after SpaceX starting to compete with them for heavy launch contracts and everyone realized that Russia could stop deliveries because of political considerations.
Meanwhile, Space has been continuously investing in new rocket technology, primarily with their own money. They haven't made any profit yet, it's ongoing reinvestment.
As this article shows, they are even working on extending the state of the art by extending CFD technology so that rocket engine design can benefit from advanced computation capabilities.
So how much new technology did ULA produce? What did the taxpayers get for the $1 billion per year above and beyond paying for actual launches? Sound of crickets...
Welcome to our post capitalism system. Entrenched special interests get guaranteed profit and government subsidies, obscene tax breaks and use government regulation to keep out any competition. SpaceX just got hit by the regulation trap: US Air Force Overstepped in SpaceX Certification. The report came out about two weeks ago well after the damage was already done. Business as usual. No one will be held to account.
This obvious sabotage resulted because the USAF/Lockheed/Boeing are for all practical purposes a unified conglomerate. They are all insiders, The military and government employees know that as soon as they leave the US payroll they will go to the (not really) civilian side and make even more money. When they retire from their civilian jobs they get two retirement packages: double dipping.
Why is Snark Required?
I'm not a native speaker, but even I can see that the grammar in the summary is just plain awful. Who edited this piece? Kids from kindergarten?
Man, I hated that class. One equation taking up half a page, with the audacity of including an error range of +/- 500%
Waa.... waaa... waiitttt! Where are the adults hiding in this game? OK, I get it April 1st only two days off.