ULA Innovation: Integrated Vehicle Fluids (IVF)

[Damon Hill]

Good to know that problem was solved.  I haven't had the best experiences with aluminum engines.  The development engine has iron sleeves because that was a cost effective solution and reasonably light; it will be interesting to see what all the flight hardware finally looks like.

I've seen impressive videos of multi-axis CNC machines ripping out complex engine blocks from solid aluminum blocks.  Certainly this isn't any more expensive than fuel cells; micro-turbines were considered and rejected as well.  In general, IVF development tries to avoid complex, maximum performance solutions in favor of cost-effective and reliable.  I think that's a sign of a well-run program.
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[jongoff]

1) what is the weight saving of IVF?

Weight savings through elimination of hydrazine, He, and most batteries have been suggested as 500 kg, but for longer duration missions with additional tankage and batteries thus no longer required, the savings should be even greater.  I've seen suggestions that payload increases could amount to a ton on some missions.  Better management of boiloff would contribute, too.

Presumably the final figures will vary a lot with specific missions and further development of systems.  It will be interesting to see how this translates to essentially free additional payload capability without any changes to the RL10 and the Centaur stage basic design.

I thought the paper suggested a 10% dry mass savings for normal missions, which would be closer to 250kg. Still a respectable savings. Hopefully as the design matures, they'll have a better handle on the performance increase.

~Jon

[Lar]

I love IVF, you've heard me rave about it before. I just have one complaint...   what is taking ULA so long

[Newton_V]

I love IVF, you've heard me rave about it before. I just have one complaint...   what is taking ULA so long

They had a proposed mission for first flight.  That customer essentially said: "not on my mission".
I suspect this will be the response for most DoD/NASA missions....

[Robotbeat]

Sounds like it'd make Centaur (or whatever the new upper will be called) into basically a ready-to-go crasher (or uncrasher!) stage for a lunar lander.

[john smith 19]

They had a proposed mission for first flight.  That customer essentially said: "not on my mission".
I suspect this will be the response for most DoD/NASA missions....

This is why I wondered if it's possible to test smaller sections of IVF on other missions. Thrusters, battery pack, starting and stopping of the IC engine.

Otherwise it looks like IVF is an all or nothing  proposition. In which case you need a mission that's got enough spare launch capacity to carry it as a secondary payload.

I suspect the number of missions that could carry a whole package in addition  to the standard GHe, batteries and Hydrazine and the full IVF test package is quite limited. 

[kevin-rf]

Just throw another Solid on the Barbi and you have the margin you need

[dror]

What makes the choice of piston internal combustion engine?
Why not fuel cells or wankle or others?

[Jim]

This is why I wondered if it's possible to test smaller sections of IVF on other missions. Thrusters, battery pack, starting and stopping of the IC engine.

The thrusters (ACS and ullage) can be tested on other missions after payload separation

[Jim]

What makes the choice of piston internal combustion engine?
Why not fuel cells or wankle or others?

read the documents

[acsawdey]

What's so very interesting to me is how much they've pulled together off-the-shelf automotive technology in IVF:

* The ignition coils are used on the GM 5.3 v8 as found in chevy pickup trucks:
http://www.rockauto.com/catalog/moreinfo.php?pk=1002325&cc=1445445&jnid=972&jpid=4
* Dry sump lubrication is a pretty standard thing in many forms of racing or for piston aircraft engines that must operate in any orientation. For IVF they make additional use of this to make sure that any hydrogen that bypasses the piston rings is scavenged and burned. Standard design for scavenge pump, probably the oil/gas separator is unusual in that it needs to operate in zero g.
* The flathead configuration was chosen because it gives them an extremely simple valve train, and the ability to extract more heat from the exhaust into the coolant.
* HV LI-ion battery system & starter/generator similar to hybrid vehicles
* off-the-shelf piston rods
* Off the shelf roller bearings for crank & camshaft (reading between the lines a little on this one)
* crankshaft, camshaft, and pistons are all similar enough to normal automotive practice that there are any number of suppliers you could hand specs to and get back finished parts for a very modest amount of money (by space standards).
* picking a company like Roush leverages all this because they know where to get everything needed to build a custom IC piston engine completely from scratch already.

[Damon Hill]

What makes the choice of piston internal combustion engine?
Why not fuel cells or wankle or others?

This question has been asked and answered multiple times: enthalpy.

[the_roche_lobe]

Is the twin engine setup shown in those simulations just notional or is the first flight actually going to use a twin engine Centaur? Would a single engine Centaur need only one ICE?

P

[kevin-rf]

I wonder, the rendering to me looked like the two engines had nozzle extensions that had not yet been deployed...

[Damon Hill]

I've seen illustrations of single-engine Centaurs with two IVF platforms; I presume dual units are for redundancy and to locate thrusters symmetrically.   IVF isn't for the RL10 only, it supports the entire stage including multiple engines.

It appears nearly all of the hardware is located on the compact platforms, a marked contrast from the clutter of tanks and sundry boxes on the current Centaur and Delta upper stage.  This include an internal combustion engine, a battery, two not very large tanks to hold moderately compressed hydrogen and oxygen gas, inverters and control electronics, and various attitude control thrusters, and one or two settling thrusters.  Power for various functions is both electrical (300 volts) via an alternator/starter that also functions as a flywheel, and a mechanical takeoff from the crankshaft for pumps.   The system could support a much larger thruster and propellant pumps for maneuvers that don't require the full power of a RL10 engine.

About the only thing IVF lacks are horns, headlights and windshield wipers.  Perhaps these are options, too.  Consult your ULA dealer.

[sdsds]

IVF works beautifully in concert with fuel cells and solar electric systems.  You let those systems handle long-duration low-level power demands and turn IVF on when you need to do heavy lifting. This enables them to be compact and light since they don't have to handle peak loads.  You can even eliminate dedicated controllers and power processing units which are major elements in the cost of those systems. The mission transition time is dependent on tank thermo, power level and other stuff but its usually after many days. 

I didn't understand this bit about "mission transition time." What exactly happens "after many days?"

Thanks!

[Jim]

Is the twin engine setup shown in those simulations just notional or is the first flight actually going to use a twin engine Centaur? Would a single engine Centaur need only one ICE?

2 pods with thrusters are required on every stage.  The numbers of each item in the pods is determined by the redundancy scheme they want to employ.

[MP99]

An aluminum block might be fine here.  Even the Vega came with a 50,000 mile (~80,000 km) warranty.

That's OK then. Super Synchronous goes to ~80,000 km.

Cheers, Martin

[mikes]

This engine runs so rich (GOX/GH2 has an amazingly wide flammability range) that I think it might not even need steel sleeves, though I might be wrong.

Do you know what mixture ratio it's designed for?

I believe Earth ICEs usually run pretty close to stoichiometric but they're kept cool by all the nitrogen in air. Even to match typical Earth ICE temperatures you'd need tons of unburned hydrogen so I'm skeptical of the no-steel-needed conjecture (but am not an engineer). It's certainly plausible that they might run it that fuel-rich so I'm not saying it's wrong, just I'd like to see more evidence before I'm convinced.

From http://tinyurl.com/ula-ivf2012 page 5
"Approximately 2 kg/hr of hydrogen and half that amount of oxygen will be consumed at low power settings"

I make that 16x richer than stoichiometric.

[TrevorMonty]

An ICE stage without main engine ie no RL10 could be used as a fuel tanker. Deliver it to orbit as payload on any LV eg FH,D4H. Once in orbit it can wait for a upper stage which needs topping up or deliver its self to a fuel depot using small thrusters. One of the papers stated the ICE driven pumps could feed a 500kg thrust engine, which should be enough for station keeping of 20mt-40mt plus enable it to be deorbited once empty.

ULA had an article on fuel depot article where a SLS class LV was launched with upper stage tanks partially loaded with LOX but fully loaded with LH. It topped its tanks up with LOX from a fuel depot before going to BLEO. The idea was to enable it to carry a heavier payload. The reasoning behind full load of LH was a) it was lite and b) it was harder to store in fuel depot without boiling off. For this situation the ICE stage would only carry enough LH for station keeping.