What happens when hydrogen meets oxygen?

[Ki Man]

i'm trying to design somewhat of a jet engine but running off of hydrogen... i'll post it on here when I'm don't but before that can anyone tell me what happens to hydrogen when it meets oxygen? does it burn immediately or do you need some type of charge or something to ignite it?

blame my horribly obvious question on my teachers for not teaching me this in school yet

i know hydorgen is very unstable and will very likely start fire but is it imediate or do you need some type of spark to start it

 

[Ki Man]

21 views and no replies...

*cricket chirping*

 

[Cyrus]

LOL! Please explain how your jet engine would work in practicality? Is it going to fly through a hydrogen rich atmosphere?

 

[Ki Man]

no. I'm going to try to use it as a fuel for flying around Earth's atmosphere because economically and environmentally hydrogen is a very good alternative to jet fuel. it won't cause pollution and is easy to produce

 

[Ki Man]

maybe not designing a new engine but redesigning/modifying the existing engine designs.

 

[faust9]

it won't cause pollution and is easy to produce

Elaborate on the process for H2 production, transportation and storage please.

 

[Ki Man]

H2 separates from water when you add electricity. the water separates into hydrogen and oxygen, you can take the hydrogen and then put it into a special tank that won't leak, like the ones used to transport chlorine or something if people are really that worried. when you transport the hydrogen its going to be treated like any other flammable hazmat material and for storage, the tanks can be stored in a medium sized concrete, well ventilated storage shacks about 20 feet wide and be kept a good few dozen yards away from anything else in the area.

maybe not the best way to put things but you get the basic picture right

 

[Danger]

You might be better off going with a rocket converted to air-breathing rather than a turbojet. I'm not sure about that, but it seems to me that the existing fuel storage and delivery systems, as well as nozzle design, would be easier to use than trying to alter a system that's designed for liquid fuel.

 

[Ki Man]

yea I've already thought of that its not really that complicated. I've thought of air-breathing rockets before. you can probably meld together the concept of a pulse detonation engine with an air breathing rocket to create a new line of air craft.

i think i have designs for both of them down already. i just need to jot down my horrible horrible sketches now

 

[Q_Goest]

can anyone tell me what happens to hydrogen when it meets oxygen? does it burn immediately or do you need some type of charge or something to ignite it?

There is a small amount of energy needed to ignite hydrogen and oxygen. You can have them together without igniting. Something as small as a static electric spark is sufficient to ignite them.

 

[sid_galt]

tell me what happens to hydrogen when it meets oxygen? does it burn immediately or do you need some type of charge or something to ignite it?

It needs to reach the appropriate temperature to burn.

i know hydorgen is very unstable and will very likely start fire but is it imediate or do you need some type of spark to start it

In jet engines, some special provisions are made so that when the flame starts, it does not blow out. Initially a source of energy to ignite the mixture of H and 02 is needed in jets but after that the flame provides that energy.


Why do you want to make an H2 powered jet. It will not decrease pollution because H2 itself needs electricity to make (unless you are not using electrolysis). Electricity comes from coal. And storage is a huge problem with H2.


As for pulse detonation engines, I would seriously advise you against experimenting with them unless you have access to a proper lab. Should a disaster occur, it may be fatal.

 

[Spectre32]

It needs to reach the appropriate temperature to burn.



In jet engines, some special provisions are made so that when the flame starts, it does not blow out. Initially a source of energy to ignite the mixture of H and 02 is needed in jets but after that the flame provides that energy.


Why do you want to make an H2 powered jet. It will not decrease pollution because H2 itself needs electricity to make (unless you are not using electrolysis). Electricity comes from coal. And storage is a huge problem with H2.


As for pulse detonation engines, I would seriously advise you against experimenting with them unless you have access to a proper lab. Should a disaster occur, it may be fatal.

Yeah i'd tend to agree with this statement. H2 is a poor choice for fueling(at least in natural aspirated engines, to which are not in a more "durable" enviroment..IE an automobile engine). If i were you I'd suggest looking at other petrolum based designs, or further into the RAM/SCRAM jet region. I'm not saying your desgin is impossible, but a lot of research and money has gone into Hydrogen. If it was a feasble idea to have a jet engine run on it, there be talk about it in the news and such. I'd do a search and see his anyone has conducted expirments with such an idea, and then go from there.

 

[faust9]

H2 separates from water when you add electricity. the water separates into hydrogen and oxygen, you can take the hydrogen and then put it into a special tank that won't leak, like the ones used to transport chlorine or something if people are really that worried. when you transport the hydrogen its going to be treated like any other flammable hazmat material and for storage, the tanks can be stored in a medium sized concrete, well ventilated storage shacks about 20 feet wide and be kept a good few dozen yards away from anything else in the area.

maybe not the best way to put things but you get the basic picture right

I asked my question(s) for a reason. 1) H2 is a little hard to store. H2 molecules are small---small enough to migrate through a crystal lattice with some ease---and as such lopng-term storage can be a problem. Another problem with the size of the H2 molecule is a corrosion mechanism called hydrogen embrittlement. Essentially, H2 will leech into a material(especially when the material is heated) and change the xtal structure resulting in a more brittle material.

As for production, it requires electricity, as you said, so simply converting to a hydrogen buring does not mean less pollution. The source of electricity used to split the H2O may actually pollute more then a conventional engine---I have an oil fired emergency substation near my house as an example.

Well, good luck with your project and keep H2 corrosion in the back of your mind.

[edit] I wrote this last night but I closed my laptop before it posted. I opened it today and my laptop left off where it was before I closed it so some information was repeated. Sorry.

 

[FredGarvin]

To chime in here and reiterate what has already been said, you need a spark source to initiate the combustion of H2 and air. We use small torches as a start mechanism in testing on our engines that do not have igniters in them. Of course, I am sure that since you are even thinking about H2 that you are well versed in the safety precautions required with H2 usage.

BTW...what exactly is "somewhat of a jet engine?"

 

[Cliff_J]

To reiterate again but focus the attention on the real problem, the pollution given off by jets seems really bad if you watch a plane taking off and see the giant plume of smoke with visible particulate matter.

But overall electricity generation creates a LOT more bad pollution than aircraft and cars and ships and forest fires and just about everything else put together. The media likes to focus on a car tailpipe, but the real problem is in the coal power plants and the places with fast growth like China are going to really complicate the problem.

So its like a sad irony that the typical enviromentalist answer to pollution is electric cars or a hydrogen economy without a plan for clean generation that makes sense. I personally like the idea of distributed solar but it has its own problems in the current technology where the construction of the silicon panel has a large electricity requirement to produce the panels in the first place.

A complex problem like energy management needs a comprehensive solution and those don't fit into media soundbites and campaign pledges very well at all.

 

[Ki Man]

i have an idea that will generate electricity without pollution, but i still need to test it. its my science fair project. it'll be done in a few weeks.

AND hydrogen is a bad idea now that i think about it i was just considering the possiblities.

 

[sid_galt]

i have an idea that will generate electricity without pollution, but i still need to test it.

The best way to generate electricity without high levels of pollution is nuclear power.

As for electricity without pollution, what fuel will you be using? I hope you are not talking about some idea which violates the laws of thermodynamics.

AND hydrogen is a bad idea now that i think about it i was just considering the possiblities.

Don't give up. There is intensive research going on to solve the storage problems of hydrogen because of its potential to be used in fuel cells.

 

[Cyrus]

As for electricity without pollution, what fuel will you be using? I hope you are not talking about some idea which violates the laws of thermodynamics.

My solution is rickshaws, lots of them. :-)

 

[Ki Man]

technically i don't think it breaks any laws of thermodynamics. if it works i'll post it on here ASAP and nobody take my idea i have at least 6 witnesses that will testify that it was mine. as long as the Earth is in tact it will work.

i think there's a 75% chance of it working. i'll see if i can get it to work this weekend.

 

[blimkie]

if your idea works will it be able to provide large amounts of electricity or atleat enough for one household? That would be neat if it hasnt been thought of before and it WORKs.

 

[Ki Man]

hmm... i have some free time on my hands right now... maybe i can get it done tonight.

how much power it will produce depends on the scale of it. i will explain more later. i am not giving anything away right now.

 

[blimkie]

well get on it lol! my brother made an electric generator for his science fair but his was just a windmill with copper coils powerd by a hair dryer. (since he wouldn't be able to make wind blow in a classroom!)

 

[Ki Man]

darn. air leaks have stopped progress for today. i need to find a better way to stop air bubbles, but I'm only using household items because i lack the proper supplies. my dad won't let me go home depot and get pipes and junk so I'm stuck using straws, a waterbottle, and chewing gum. i think I've solved one of the air bubble leaking areas so i just need to do the same thing to the other area and it should work.

 

[Danger]

my dad won't let me go home depot and get pipes and junk

Tell him that you have to disassemble his VCR for parts and he'll drive you there.
By the way, if the formula hasn't changed much in the last 40 years, Juicy Fruit gum hardens to the consistency of JB Weld and seals just about anything.

 

[Ki Man]

hmm... juicy fruit gum?

 

[jaap de vries]

i'm trying to design somewhat of a jet engine but running off of hydrogen... i'll post it on here when I'm don't but before that can anyone tell me what happens to hydrogen when it meets oxygen? does it burn immediately or do you need some type of charge or something to ignite it?

Hypergolic propellants are a fuel and oxydizer which ignite spontaneously on contact with each other. Hydrogen is not Hypergolic but has a very low activation energy and is exstremely exthothermic in its reaction with oxigen. Storage is the main problem with hydrogen as a liquid fuel since it needs to be cryogenically stored and it has a very low molecular weight. (Ask yourself why the spaceshuttle main fule tank is so big in comparison to the SRB's)

 

[Danger]

For safe storage of hydrogen, I'd be inclined to go with magnesium hydride. It traps 1g/cc when chilled, and releases it when heated. Much cheaper, but less efficient, is iron-titanium hydride.

 

[Danger]

hmm... juicy fruit gum?

A quite tasty concoction of Wrigleys.

 

[Ki Man]

straws are very bad. I'm going to force my dad into taking me to home depot this weekend somehow and buy the proper platic tubes and maybe some kind of small tank because i can't seem to get the waterbottle just right.

science fair projects aren't going the way they should. this isn't much of a science fair... its more like creating a presentation on some kind of stupid poll like other groups and having the teacher grade you on your use of the scientfic method. we are the most original group with our concept. everyone else is doing pointless studies like, which works better, gatorade or water.

when they said science fair i was thinking more science and less... pointless data and charts that holds tons of room for human error.

are all science fairs like this or is it just the best my peers can come up with at our level

 

[Cliff_J]

Ki Man - I think it sounds like you are expecting to have an Earth'shattering discovery with your science fair project. Let's say you did, if you couldn't tell people about it, what good would it do? There are many examples in history of people with insights that went unused for years or were forgotten when someone else came along and did a better job of presenting their findings. Da Vinci is probably one of the most cited for this, a lot of his inventions were practical long before they were ever used. How different would life for us be if his plans for scuba or parachutes or whatever had been implemented during his lifetime?

The expectation with a science fair is not to create something new but instead to learn how to do something. Correctly demonstrating the ability to use the scientific method to determine A instead of B and explaining those findings is very important, even if its about something some people would be aware of or could find published already.

Regardless, would you not want to practice the process with something small first, even if less than a completely new perspective on a problem that needs solving? That is the point, that if you did discover something new and insightful, that you could explain it in a way that would allow your discovery to accepted by others and utilized whether it be for the common good or commercial success.

 

[Ki Man]

i'm not expecting anything Earth'shattering from my project or from the other projects, i just think the other projects could have aimed a bit higher than water vs gatorade, which is an important study, nonetheless, but is very highly cliched as an expirement

 

[Danger]

On the other hand, you could try using Gatorade as a fuel. How well does it burn compared to water?

 

[Lapin Dormant]

Ever seen the guy with the "Rocket backpack" he's using Silver Ag as a catalyst, and reacting Hydrogen Peroxide H₂O₂ to achieve a good discharge rate, for thrust, but caution is needed as the temperature can easily hit 750° F

 

[Lapin Dormant]

Oh Yes, Gatorade is simply the "Cure" (Discovered) for Dehydration, a Liter of Water, a Handfull of Sugar, and a Pinch of Salt .. .. .. Roughly <plus coloring and Vitamin C etc.>

 

[Danger]

Ever seen the guy with the "Rocket backpack"

But of course. Here he be:https://www.physicsforums.com/showthread.php?t=71717&page=2&highlight=Captain+Rollerball"

 

[Lapin Dormant]

**[/color]Ahem**[/color] This is what I had meant, How Stuff Works and it does work.

 

[Danger]

I've been seeing those things for decades, but never a practical one. I still like the Captain better.

 

[Ki Man]

they don't have a practical one because you can only fly for about 30-60 seconds usually. 5 minutes would be a major breakthrough.

 

[FredGarvin]

My company developed and flew a turbine engine version of that back in the early '60's. It worked pretty well. I have seen a fair amount of video of it flying.

http://www.uncleodiescollectibles.com/img_lib/Jetpack 1 10 6-15-4.jpg

 

[Ki Man]

what was its maximum airtime and speed

 

[FredGarvin]

If I remember correctly it was about 70 mph for about 30 minutes. I do remember someone saying that it did have some controll issues over water though. I'd have to ask some of the "seasoned" folks around here for more particulars.

 

[Danger]

Thanks for the pic, Fred. I vaguely remember reading something about it a few decades back, but never saw it before. That sucker must weigh a couple of hundred pounds, though. I'm guessing that both it and the rocket type would probably be frowned upon for commuter transport based solely upon the noise involved. Such things might have to stick with helicopter rotors until someone comes up with a way to put a muffler on a jet.

 

[Ki Man]

see with jet powered cars and stuff for everyday use, there comes a bunch of problems

problem: birds and small animals like nearby cats getting sucked into engine (this problem is solved a lot in the commercial airliners and stuff with small birds, but we've never had to deal with scruffy climbing up on your back while you put on your jetpack)
problem: humans getting sucked into engine (whoa! i knew i shouldn't have worn this baggy jacket. oh well. i'll just sit and wait for the paramedics)
problem: noise level of having a jet engine in a neighborhood (keep it down over there! don't make us shoot you out of the sky)

wouldn't a modified and enlarged version of a rifle's silencer help decrease the noise level made by a jet just a little at least

 

[Danger]

wouldn't a modified and enlarged version of a rifle's silencer help decrease the noise level made by a jet just a little at least

Yeah, but it wouldn't provide any propulsion then. Also, there's no such thing as a silencer, just suppressors. Keep in mind that an effective one for a .45 auto pistol is from 2 - 4 inches in diameter and 10 -14 inches long. One for a high-power rifle is much larger. The whole point of the thing is to capture all of the expanded propellant gas and then release it slowly. You need enough internal volume, plus baffles, reversal plates, etc. to accomplish that. Think of how much gas is coming out of a turbojet.

 

[Danger]

My 'edit' button still isn't working. I meant to add that a jet engine will not continue to run when its exhaust is blocked, any more than a piston type will.

 

[sid_galt]

see with jet powered cars and stuff for everyday use, there comes a bunch of problems

problem: birds and small animals like nearby cats getting sucked into engine (this problem is solved a lot in the commercial airliners and stuff with small birds, but we've never had to deal with scruffy climbing up on your back while you put on your jetpack)
problem: humans getting sucked into engine (whoa! i knew i shouldn't have worn this baggy jacket. oh well. i'll just sit and wait for the paramedics)
problem: noise level of having a jet engine in a neighborhood (keep it down over there! don't make us shoot you out of the sky)

wouldn't a modified and enlarged version of a rifle's silencer help decrease the noise level made by a jet just a little at least

Even if you solve all the above problems, you are never going to see widespread use of jet engines in cars. They are too expensive and require much more maintainence than ordinary engines.

Some sort of a gas turbine engine might already exist in cars though. You have a turbocharger which increases air pressure and you have a turbine which runs on exhaust gas. But these are centrifugal compressors and turbines. For a good efficiency jet engine you will need axial compressors and turbines which are more expensive than their centrifugal counterparts.

Jet powered cars have been made e.g. Spirit of America but they are for specialized purposes only.

 

[FredGarvin]

Even if you solve all the above problems, you are never going to see widespread use of jet engines in cars. They are too expensive and require much more maintainence than ordinary engines.

That's true and not so true. Many turbines today are operating with thousands of hours between overhauls. The issues would then become would the average person really be willing to be more vigilant with their day to day responsibilities in general maintenance and when the repairs/overhauls do happen, they would be more extensive than, say, a v-6 would. That being said, the major gripe most people have today is that many feel engines are too complicated now and that they can't be worked on by the lay person. So I think there's a bit of a tradeoff there. However, the cost factor is what is going to be the killer. Until production numbers get very large, indeed the cost will be pretty high.

Again, not to toot our horn, but my company, among others, developed and tested a vehicle with a turbine driven alternator. This was the initial vault into the hybrid technology. The turbine drove a alternator that kept the batteries charged. It worked well because the turbine could operate at constant speed at or near it BEP. The batteries did the actual vehicle moving.
The noise was not terribly bad, but it was noticeable. Personally, I think this configuration would hold the most hope for vehicles with turbines in them. I also think that they would be today's best bet at an almost zero emissions vehicle.

 

[FredGarvin]

wouldn't a modified and enlarged version of a rifle's silencer help decrease the noise level made by a jet just a little at least

Not really. Turbines are usually pretty sensitive to back pressure. We do tests where we intentionally do that and the increase in back pressure has the most notable side effect of an increase in turbine temps which now throws your cycle off and puts more stress on the turbines. The most notable method of silencing today is the mixing assemblies at the rear of the engine. The idea is that mixing the colder bypass flow with the exhausted core flow does help to decrease the noise.

 

[Lapin Dormant]

If you would want to silence it, use a Counteracting sound wave as to annul the emiting wave.

Means use a microphone and computer to pick up on the sound emitted, generate a Counterwave to it, broadcast it back at the originating sound wave, the Two cancel each other, and the noise, disappears.

Practical solution.

 

[FredGarvin]

If you would want to silence it, use a Counteracting sound wave as to annul the emiting wave.

Means use a microphone and computer to pick up on the sound emitted, generate a Counterwave to it, broadcast it back at the originating sound wave, the Two cancel each other, and the noise, disappears.

Practical solution.

Not so practical. The noise being emitted is a broadband frequncy, it's not a nice, simple single frequency. That means whatever is doing it has to have the computing power, plus the output power to be able to mimic what is coming out in real time.