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My understanding of a basic turbo system is that it forces air into the intake at an accelerated rate.
I know for a fact that the expansion of liquid oxygen (LOX) to gaseous oxygen (GOX) is 860 times: basically, 1 ounce of LOX = 860 ounces of GOX.
Because liquid oxygen is so concentrated, it
is
naturally HIGHLY flammable (if anyone questions this, simply look at the warnings on a LOX servicing cart). Ok, I know oxygen's technically not flammable, but it sure as hell supports combustion in a very big way!
Imagine this: a single (very small) drop of LOX in each cylinder
Need I say more?
Liquid Oxygen
http://www.medox.org/liquid.htm
supplying oxygen to the home patient [baconbrain, Jun 29 2006]
Salmon powered engines
http://en.wikipedia.org/wiki/Lox_(salmon)
now I know why they can swim upstream so fast [xenzag, Jun 29 2006]
LOX
http://en.wikipedia.org/wiki/LOX
[BJS, Jun 30 2006]
sphere volume equation
http://www.aaamath....-volume-sphere.html
Simple equation to find the volume of a sphere given it's radius. [Custardguts, Jul 11 2006]
[link]
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and they put this stuff on bagels !!!!! |
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Please, do: Let us know how the liquid O2 would be stored in the vehicle, and how it would be metered into the intake manifold or combustion chamber. |
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I've used liquid oxygen tanks a couple of times before...
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If it was comparable to the price NOX then I'm sure they would be using it for cars.
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Oh and change the name of this idea to "LOX for boost" or something similar, because this doesn't have to use a turbo for its boost. |
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//Because liquid oxygen is so concentrated, it is naturally HIGHLY flammable (if anyone questions this, simply look at the warnings on a LOX servicing cart).//
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Wow very interesting. After 10 years in the Scientific field I am at a complete loss to understand when Oxygen became a Flammable Substance.
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Oxygen does not Burn. It is not Flammable in any way. It is however an Oxidiser(where do you think that word came from) and as such will supply oxygen to a Burning flame allowing it to burn more efficiently and completely.
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I suppose injecting liquid oxygen could work but the giant refrigerator you would need to carry around with you to keep it liquid would kill any performance gain. This is really useless in that you could not pump enough fuel into the engine to take advantage of the oxygen that was available(most engine dont even use up what is injected during a normal engine cycle) |
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Liquid oxygen tanks don't require refrigeration like jhomrighaus said they do, refrigeration is only required to liquify the oxygen before they put it into the tank. And isn't oxygen required for nearly all combustion. There wouldn't be a burning flame without oxygen like jhomrighaus said.
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You wouldn't have to inject the oxygen into the engine as a liquid, you could convert it to a gas first like medical liquid oxygen tanks do. |
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On things technical, I've learned that if [jhomrighaus] says pigs do fly I should invest in a sturdy umbrella. |
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The atmoshpere is about 21% oxygen already. A turbochargers job is to force more air(read more Oxygen) into the cylinder. In a properly operating engine there is always oxygen leftover(thats what Oxygen Sensors are designed to detect) so this is probably redundant to the Turbo or the Nitrous or the nitromethane that you would otherwise run. BJS is correct that for Combustion reactions Oxygen is required(one of the three sides of the fire triangle) BJS you are correct that you do not need to have a refrigerator to store the oxygen but as with all liquid compressed gases you will constantly be losing Oxygen as the tanks vent to keep to a safe pressure(thats why hospital Bulk Oxy tanks tend to hiss all the Time)
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[methinksnot] Thanks for the compliment. |
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If the tank constantly vents, then maybe it could constanly vent to the engine as it leaks. |
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/1 ounce of LOX = 860 ounces of GOX./
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Bad, bad, bad science. 1 ounce LOX = 1 ounce GOX due to conservation of mass. Volume will increase at the same pressure though, which I think is what you are getting at. |
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//hospital Bulk Oxy tanks tend to hiss all the Time//
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Bulk tanks use thinner walls, thermal insulation and occasional venting. That combination is known as 'cryogenic storage', I think. The LOX is cold, the tank pressure is low. The LOX boils off to keep the temperature low.
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I found a link about portable medical LOX tanks. They seem to do much the same. |
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So if there is oxygen left over after complete combustion, would adding more fuel make more power? Not really. The reason a turbo makes more power is because it compresses the intake charge. This charge will expand again in the cylinder which adds to the power output. If you think of the engine as a pnumatic (air) driven motor this makes sense. |
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/1 ounce of LOX = 860 ounces of GOX./ 'Ounce' is sometimes used to mean 'fluid ounce'. But it wouldn't hurt to use unambiguous units.
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If you did this continuously, you could also burn much less flammable fuel, such as kerosine. The engine would also run in space. And under water. |
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What [wittyhoosier] said. |
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//The reason a turbo makes more power is because it compresses the intake charge. This charge will expand again in the cylinder which adds to the power output. If you think of the engine as a pnumatic (air) driven motor this makes sense.//
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[wittyhoosier] The boost pressure of a turbo charged engine generally is in the 10 to 15 psi range and might be up in the 20 to 25 psi range for high performance motors(same for Supercharged Motors). The pressure of the incoming air has absolutely nothing to do with the extra horsepower output of a turboed engine(the HP loss to spin the turbo is greater than the HP you would gain from its re-expansion in the engine). The power comes from the fact that the increased presure means more oxygen is available which means more fuel can be injected for each cycle of the piston, more fuel and air(oxygen) means more power. Turbo charged engines have almost nothing in common with compressed air engines. Your typical Air tool(small pnuematic engine) operates at 60 to 100psi and they are incredibly inefficient.
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[witty] you need to do a lot more research on how turbos work. |
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//The engine would also run in space.//
Not for very long. The radiator still requires an ambient fluid source to dump waste heat into. And good luck getting thrust without a reaction mass. |
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What [jh] said. High power outputs (on race engines, for instance) are sometimes achieved by running the engine rich (higher fuel:air ratio than is chemically correct, ie extra fuel). All of the power comes from burning fuel to release energy, so you get as much fuel in there as you can burn. That value is governed by how much oxygen you have available, so a turbo pumps air in under pressure to increase the amount of fuel that can be burnt. |
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//the giant refrigerator you would need to carry around with you to keep it liquid would kill any performance gain.//
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You don't need a "giant refrigerator" to store it. The LOX converter on MC-130E aircraft holds 25 liters and is only about 2 feet in diameter (it's a sphere). I don't know exactly what materials the container is made of, but it consists of an inner sphere and an outer sphere, with a vacuum gap between the 2 layers. It's not a large container at all. For something much smaller, like a car, you'd only need a liter or so, and you could easily fit something that small under the hood of many vehicles (I can store a 2-liter Coke bottle in mine).
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As far as metering into the combustion chamber, I admit I have no idea how that works having never done any work with metering devices, but I know it can be done.
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Also, perhaps I was erroneous in using the term "turbo". This wouldn't necessarily require constant metering if it is only used for quick boosts, the way NOX is. |
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By very quick mental maths,a two foot sphere has a volume approaching 120 litres - that's over four times 25 liters [sic] - what is the rest of the volume doing [21]? |
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I don't claim to know exactly what's (aside from LOX) IN the sphere, copro. I've never opened one, that was a job for the electro-environmental specialists. Perhaps most of it consisted of the vacuum insulation layer. I also may have slightly overstated the size. I've never been very good at eyeballing size estimates... I remember it was slightly larger than my head, however... and some would quote 2 feet as a close estimate of THAT...
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I'll call a friend at the base tomorrow and find out exactly how large it is. |
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By the way, copro, your math is off. There's no way a 2-foot sphere holds 120 liters. The converter is indeed 2 feet, and holds 25 liters. Do the math again, and take your time. |
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Take a 2-ft diameter globe and try to dump 60 2-liter coke bottles iside. It isn't going to happen. |
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I get 113 litres. V (sphere) = 4/3*Pi*r^3
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-see link for reference if it makes you feel better-
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[21 quest] I'm really not meaning to pick on you, but do you actually own a 2-foot diameter globe? they're bloody huge, easily over a hundred litres just by looking at them. It's cool that you don't know the math, but generally simple equations don't lie.
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I'd imagine the oxygen-storing sphere you talk about has a very generous insulating layer. I'm guessing about 12 cm, in fact, given that the inner sphere holds 25 litres. |
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Thanks [custardguts] - like I said, I estimated. I was seven litres out - I must try harder.
I was leaving it as an exercise for the reader to guess where the rest of the volume had gone, mostly to get the OP to understand how difficult it is to carry that stuff around.
I failed.
//Liquid oxygen tanks don't require refrigeration // Maybe, but make sure those burst disks don't vent anywhere dangerous. Many common substances, even metal filings, will spontaneously combust in pure oxygen. |
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Ill ignore the storage issue, as it has already been discussed. The issue with LOX as stated above, is that it oxidizes everything when under enough temperature and pressure. This includes the aluminum in your engine top end. Even under normal operating conditions, which after you inject LOX it would no longer be normal, a concentrated oxygen source will oxidize the aluminum in the runners, and iron in the valves, valves seats, etc. The result being loss in compression or catastrophic failure. Thats before you mix with fuel.
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Now after you mix with the fuel this oxidation is much less likely but still there. This is because even the best engines only have a 95% perfect fuel to air (or oxygen) mixing ratio. Again, this is why adding more fuel for the same air gets you more power. The leftover LOX in the combustion chamber would oxidize the piston, head, rings, and cylinder wall which eventually would create a failure. (Anyone ever seen a windowed piston, its kinda cool:)
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All that being said, I take my experience from use of NO2 which is similar in context. (Although it requires pressure and temp to crack the extra O off, so its a little easier on the engine.) NO2 still creates the same problems as LOX, but the effects are slower. In the end its a good Idea, an alternative for NO2 as it has a higher potential power density. But I dont think it would work for anything but racing. |
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Certainly the engine would run in space. Anyone with a little understanding of thermodynamics could design a radiator that would dump the waste heat effectively - it would be enormous - but why would you bother? Not much traction on those asteroids... |
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By the time you built an engine beefy enough to handle the sudden jolt of power and a direct injection system for the oxygen, as well as a secondary fuel system so the oxygen doesn't destroy your pistons and a storage system for the LOX, you could have built an engine that makes more power more reliably than this system. The long and short of it? It would take way too much design and custom machining and such to ever be feasible. If you want power like this, get nitrous or better yet, a blower and nitromethane. |
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//But I dont think it would work for anything but racing.//
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That's the whole point. You don't use NOS for normal driving, and neither would you use this. |
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Adding oxygen instead of nitrous oxide probably produces less acid-rain, asthma and greenhouse effect inducing NOx in the exhaust gases, so now you can be a more environmentally aware fuel waster. :) |
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Worries aside... if we're injecting the LOX in liquid form, it's going to need to evaporate in order to react with the fuel... is the evaporation process not going to absorb so much heat out of the intake charge it won't burn correctly? |
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21_quest - I can see this working in one of two ways. You could create an entirely new kind of ICE in which there are no intake ports. LOX and H2o, and gasoline would be direct injected into the engine and burned. Then the resulting steam, because that's all you would get, could be pushed out the exhaust ports. It would be a two stroke engine of course. The water phase changing into steam would suck up all the heat of the combustion so you wouldn't need a cooling system.
The reason you couldn't just inject LOX and air into the engine and burn it is because it would burn too hot. The inert gasses in regular air expand, absorb heat and create pressure in the cylinder. With just LOX you would have one hell of a hot, low pressure cylinder!
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The other option is you could take a regular turbocharged engine and inject LOX and h2o. Water is commonly injected in turbocharged vehicles to absorb some of the heat but you would take this a step further. The only problem with this is it would be really hard to meter the LOX and h2o.
Either way this is really going to take a lot of engineering to get it to work. |
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//Then the resulting steam, because that's all you would get//
Steam contains carbon now? </sarcasm> |
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