Air breathing engines question

[mikeemmert]

<blockquote><font class="small">In reply to:</font><hr /><p>...nitrous oxide. I was under the impression that that was primarily a transient state, at least for combustion products in fuel combustion streams, as hydrogen has a higher affinity for the oxygen than nitrogen does.<p><hr /></p></p></blockquote>...nit<b><font color="yellow">ric</font></b><font color="white"> oxide. Anyway, your impression is the same as mine, it's a transient product, the LOX/air reaction cools the compressor cone. 2 H2 + 2 NO = H2O + N2. Nitric oxide is actually a stronger oxidizer than oxygen, oxygen burns in NO as the fuel.<blockquote><font class="small">In reply to:</font><hr /><p>... I don't see this as affecting ground level smog interactions.<br /><br /><font color="yellow">???*~<font color="white">...<img src="/images/icons/crazy.gif" /> <br /><br />Anyways, I don't see us flying more than 50-100 sorties a year at best, so I'd point the protesters<p><hr /></p></font></font></p></blockquote>Nah, pointing protesters is like herding cats.<br /><br />You got the wrong guy, dude. My protests concern warfare between human tribes and are confined to Free Space, where they are vociferous and eloquent. You are still thinking nuke protesters, and I <i>told</i> you, they use all kinds of pseudoscience. These guys showed me they were idiots.</font>

 

[propforce]

<font color="yellow">I have figured out that you, me, and propforce are talking past each other. ............. Good luck with your X-106 project! This sounds like something you might actually be able to do! </font><br /><br />I have not read the X-106 thread. Are you proposing using the MIPCC technique to improve jet performance? <div class="Discussion_UserSignature"> </div>

 

[mlorrey]

Yes, it allows jets of any kind, turbine, ram, scram, to be operated at higher altitudes and speeds than otherwise, because adding cold oxidizing mass to the airstream ahead of the compressor makes the jet believe it is operating in a denser atmosphere and a lower speed. Here's a graphic showing real v apparent speed and altitude with MIPCC.

 

[scottb50]

Yes, it allows jets of any kind, turbine, ram, scram, to be operated at higher altitudes and speeds than otherwise, because adding cold oxidizing mass to the airstream ahead of the compressor makes the jet believe it is operating in a denser atmosphere and a lower speed<br />I think that is a given..... <br /><br />As long as you provide fuel and Oxygen a V-8 would operate in Space, though afuel cell is probably a better way to go.I do think it would be a lot easier to use fuel cells and rocket engines. Once your out of the atomosphere that's pretty much all you have anyway.<br /><br /> I wouldn't mind having a Hydrogen fueled 59 Cadillac though.<br /><br />I would also think it simple to convert to a rocket from an air-breathing Scram-Jet, the problem becomes getting to a speed those engines would start working. If you use a rocket you might as well use it to get to orbit, if you start out with air breathing engines you add a lot of weight. <div class="Discussion_UserSignature"> </div>

 

[mlorrey]

Adding LOX and H2O, or H2O2, need never exceed 20% of the airstream mass. What results is that it ups the O2 amounts enough that the airbreathing engine is still able to combust atmospheric O2 as well as that added to the airstream. For this reason, it retains the higher Isp of an air breather, rather than the low Isp of a rocket engine. Starting out with air breathing engines gives you so much more Isp that it more than makes up for the weight. Besides those facts I have repeatedly informed you that ramjet T/W ratios range from 20-50. LH2/LOX rocket engines can't do any better than 50 either, so hydrogen rockets really have no weight advantage over ramjets. While hydrocarbon engines can get over 100, their lower Isp detracts from their T/W advantage.

 

[why06]

Propforce <blockquote><font class="small">In reply to:</font><hr /><p>Better yet, I'd just take off with the LOX tank empty. Pull up behind a KC-135 tanker and filled up my LOX before I fired up my rocket and take off to space. <font color="yellow"> [endquote] <font color="white"><br /><br /><br /><br /><br /><br />If your trying to get to Leo it's bad to use another source of take off as this would limit your payload. I say the craft could have two sets of wings.<br /><br />1. at the beggining the two modules are connected. the one with the big wings accelerate the craft as fast as possible, all the time scraping up fuel. When the tanks are fuel and a high speed and altitude are reached the lower section detaches.<br />2. the rocket module with smaller wings that carries the payload boosts up to space.<br /><br />Sure the carrier structure would be huge,but it would be reusable.<font color="yellow"></font></font></font></p></blockquote> <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>

 

[mikeemmert]

Hydrogen peroxide can detonate at above 70 degrees C.. Peroxide could probably be a pretty good turbojet booster at "low" speeds (< Mach 3). I think LOX would be better.

 

[mlorrey]

H2O2 can detonate above 70 C AS A VAPOR. As a liquid it is quite stable. Keeping it that way requires using nitrogen or helium in tank ullage space and when used in cooling applications to keep it under pressure.

 

[drwayne]

At 70 C isn't hydrogen peroxide into runaway decomposition?<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[rocketman5000]

which would basically be a detonation...

 

[mlorrey]

H2O2's boiling point is 141 C at 100 kPa ambient pressure and 90% concentration. I doubt that this temperature would be obtainable if it detonated at 70 C. The 70 C point is for peroxide exposed to ambient air, which will evaporate peroxide into the atmosphere and detonate the vaporized peroxide at that point. If instead you use an inert gas like helium to fill tank ullage under higher than ambient pressure, the risk of detonation is controlled.

 

[drwayne]

I was not referring to boiling. (Nor directly referring to detonation)<br /><br />Hydrogen peroxide decomposes - there is really not a *lot* you can do about that. (You can make it worse with contaminants, slightly better with certain stabilizers). The decomposition rate is a function of temperature - a rough rule of thumb is that it doubles for every 10 degrees C.<br /><br />Decomposition gives you water and oxygen. The process is exothermic, which means it can run away, which was why I asked the question I did.<br /><br />Wayne<br /><br /> <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[propforce]

<i>Hydrogen peroxide decomposes -...</i><br /><br />Which is why it is sometimes used as a <font color="yellow">mono</font>ropellant. <div class="Discussion_UserSignature"> </div>

 

[drwayne]

Yep, in that role it decomposes really fast - in the presense of a catalyst....<br /><br />Therein lies a challenge in monoprops - for something to be a good monoprop, it has to have an energetic decomposition path - which can make it tricky to handle.<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[propforce]

Yeah. One lesson learned in handling highly concentrated H2O2 is not to have it store in an open container outdoors. Wait till one bug drops into the H2O2.... KABOOM !! <div class="Discussion_UserSignature"> </div>

 

[drwayne]

There's a bug in the system!<br /><br />I don't know why, but the descriptions of the fuels used in the Me 163 Komet which included hydrogen peroxide - sounded so cool on the program "Wings of the Luftwaffe" when the particular narrator talked about them - yes, it is weird to think its cool when someone talks about calcium permanganate - but what can I say - I am strange....<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>