Author Topic: Ok, So It's Stupid-Now Tell Me WHY It Won't Work!  (Read 22235 times)

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Offline Tman

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Re: Ok, So It's Stupid-Now Tell Me WHY It Won't Work!
« Reply #45 on: February 07, 2012, 12:47:59 PM »
Barney Navarro metal sprayed the inside of his engine...................with a Stromberg, while playing with oxygen :-o "vaporized" was his exact word for it :wink:

Offline hotrod

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Re: Ok, So It's Stupid-Now Tell Me WHY It Won't Work!
« Reply #46 on: February 07, 2012, 12:50:49 PM »
High pressure pure oxygen and a combustible hydrocarbon do not need an ignition source the reaction is self initiated, and potentially explosive as related in the story. The oxygen begins to oxidize the hydrocarbon and the heat of oxidation sustains the reaction -- true case of spontaneous combustion.

In oxygen compressors they must be absolutely oil free, if the piston tops are contaminated by even an oily finger print it will ignite and then burn the aluminum of the piston crown.

Larry

Offline jacksoni

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Re: Ok, So It's Stupid-Now Tell Me WHY It Won't Work!
« Reply #47 on: February 07, 2012, 01:09:09 PM »
High pressure pure oxygen and a combustible hydrocarbon do not need an ignition source the reaction is self initiated, and potentially explosive as related in the story. The oxygen begins to oxidize the hydrocarbon and the heat of oxidation sustains the reaction -- true case of spontaneous combustion.

In oxygen compressors they must be absolutely oil free, if the piston tops are contaminated by even an oily finger print it will ignite and then burn the aluminum of the piston crown.

Larry
[/quote
But Larry, generally is said combustion needs heat, O2, and fuel. In your compressor example, I will buy it as the oxygen is being compressed and therefore, heated. Some chemical reactions of course produce heat. Just mixing O2 and a hydrocarbon wouldn't do that usually would it? What is the heat source of only high pressure O2 and the fuel. Not questioning your statement, just trying to understand the chemistry. If you mixed the O2 and the hydrocarbon at low pressure, and then, raised the pressure but did it in a way to not heat it,(slowly allowing the heat to dissapate) would it spontaneously combust?  Again my example of a cutting torch. I can see someone with a hose cleaning the tank making sparks somehow as McRat related.
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McRat

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Re: Ok, So It's Stupid-Now Tell Me WHY It Won't Work!
« Reply #48 on: February 07, 2012, 01:50:07 PM »
Jacksoni:

There was no spark.  The compressed oxygen hit the stoddard's solvent + dirty engine oil, and exploded.  For real.


Offline jacksoni

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Re: Ok, So It's Stupid-Now Tell Me WHY It Won't Work!
« Reply #49 on: February 07, 2012, 02:21:33 PM »
Jacksoni:

There was no spark.  The compressed oxygen hit the stoddard's solvent + dirty engine oil, and exploded.  For real.


I believe, just trying to understand the chemistry.
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McRat

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Re: Ok, So It's Stupid-Now Tell Me WHY It Won't Work!
« Reply #50 on: February 07, 2012, 02:30:36 PM »
Oxygen is very powerful oxidizing agent, look at what it does to steel.  Rust is burning steel.  It's just a slow reaction.

The reason the world around us just doesn't ignite, is because our O2 is at low pressure, and heavily diluted.

When you get it pure, and under a lot of pressure can force the issue. 


Offline Peter Jack

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Re: Ok, So It's Stupid-Now Tell Me WHY It Won't Work!
« Reply #51 on: February 07, 2012, 03:25:27 PM »
There's a reason that all oxygen regulators say "Use No Oil". Many people in the welding business can tell stories of oxygen hitting hydrocarbons and causing violent ignition with no known ignition source.

Pete

Offline oz

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Re: Ok, So It's Stupid-Now Tell Me WHY It Won't Work!
« Reply #52 on: February 07, 2012, 03:43:30 PM »
Ok just a thought
My bike is (on a flow bench) is able to flow around 140-160 cfm a minuite per cyl WOT if you wanted to charge at 1 atmosphere on top of that would you not be using around the 280-320 cfm.
If the bottle that it is to be stored in has a specific volume to start with which it will,would it not make sense to assume that if it is compressed in multiples of atmospheric pressure 2-300 bar divided by the cfm the engine uses at WOT would this not give an estimate of run time per bottle.

or have I got it all wrong

our calculations ho hum reckon an internal dimension of around .8ftx.8ftx.8ft@300 bar gives about a min damm wish i was more clued up!!! and so does beck!!!
« Last Edit: February 07, 2012, 04:11:33 PM by oz »
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Offline hotrod

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Re: Ok, So It's Stupid-Now Tell Me WHY It Won't Work!
« Reply #53 on: February 07, 2012, 07:17:20 PM »
To figure total air required:

For the NA engine  ---- ((CID x rpm/2 )/1728) x minutes x VE


CID = cubic inch displacement
rpm/2 because the engine is a 4 cycle and only intakes air on every second down stroke of the piston
1728 = number of cubic inches in a cubic foot
VE = volumetric efficiency of the engine at peak power. For a well designed head and cams with some ram effect taking place this is often 110% or so.

Multiply that by your intended manifold pressure ratio. That would give the a rough approximation of how much air at standard inlet conditions the engine would need to maintain boost. Then just figure out the tank volume you have and find the required pressure to fit it all in the bottle.

That does not account for the fact that the bottle would lose pressure as the pressure blew down, so you would also have to add enough pressure/volume so when you get to the end of the run the bottle would still be over your design manifold pressure.

You would also have to figure out how to regulate a high volume flow of air to that manifold pressure. Most air pressure regulators are only designed to handle maybe 10-30 CFM flow as in a compressed air regulator for a paint gun or sand blaster.

Then you would need to add a safety factor for the pressure drop in the lines due to friction at that flow velocity.

By the time you get done I think you will find you end up with either a very short time at boost or a very big air tank.

You could shrink the tank size a bit by using a flapper valve so the engine could start and run on atmospheric air, but only when the compressed air is flowing it would force this valve closed, allowing you to pressurize the manifold.

All that of course only useful for a time only attempt but might be useful experiment for a very small displacement engine like a 50cc motorcycle.

Larry

Offline zenndog

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Re: Ok, So It's Stupid-Now Tell Me WHY It Won't Work!
« Reply #54 on: February 14, 2012, 03:07:55 AM »
This thread and the talk about the volatile nature of oxygen reminded me about this story about PEPCON were an oxygenated solid rocket fuel plant exploded. It was a very interesting set of poor decisions that led to one huge disaster. I saw an interview with one of the firemen and he said they got the alarm and were racing to the address when the shock wave hit them on the road and they just pulled over, realizing that they needed to find out exactly what was going on before proceeding. Another part of the story covered safety training at the factory, what to do in case of fire....run away as fast as you can.

Offline Dean Los Angeles

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Re: Ok, So It's Stupid-Now Tell Me WHY It Won't Work!
« Reply #55 on: February 14, 2012, 10:39:29 AM »
The conversation about oxygen use in an engine is making assumptions about using large amounts of pure oxygen.
Even small percentages would increase oxygen content in the cylinder without the dire consequences noted.
Nitrous oxide is the better choice, but that puts you in the fuel class.
In the gas class compressed air or oxygen would absolutely develop more power.
Compressed air is a trade off to reduce drag from the supercharger. It can't put more oxygen into the system than the supercharger. Compressed oxygen would put in more oxygen and develop more power.

But you can expect the same development curve as the Jim Hall Chaparral Can-Am cars. Nope, not the super sucker.
Prior to that the 2C and 2E were the first car with really effective tall wings. In-car adjustable angle with the wings attached directly to the rear hubs.
The wing was adjustable from a foot pedal in the cockpit. That's right, no clutch pedal because it ran an automatic.

When the wings were outlawed the 2J super sucker was developed. Brilliant design to use atmospheric pressure to create traction. Way before its time.  The first race showed the true potential when it qualified 2 seconds faster than the competition. The car ran for one year and then was banned.

The rules do state that you have to have an engine driven supercharger/turbo, but don't specifically rule out compressed air/oxygen. But it won't be allowed.
Well, it used to be Los Angeles . . . 50 miles north of Fresno now.
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It's bigger than life or death! It's RACING.