Burning acetylene with oxygen in water

[NeoPTLD]

I've seen a picture of it somewhere. If oxygen is provided along with fuel, it can burn in water.

Fire just goes out as soon as its put in water though. How do I get it to burn in water?

 

[fralexandr]

i'm a bit rusty, but from my understanding:
fire doesn't get put out by simply being in water
water "suffocates" fires by preventing contact with sufficient amounts of O2 to react during combustion, as well as by absorbing energy (high heat capacity)

http://www.newton.dep.anl.gov/askasci/chem03/chem03311.htm
that professor describes how it's possible better than I do

 

[metril]

It all has to do with flame holding. If you have never taken a Combustion class, I suggest you do.

You need an attached flame. You need a premixed fuel/oxidizer by the time the flow exits the tube. However, a premixed fuel/oxidizer is very dangerous and susceptible to flashback. So, you need to compartmentalize your tube. In the lower part, you would have only the fuel flowing. Closer to the exit (region closest to water), you would inject your oxidizer. You need this flow to go through some sort of swirler and flow rectifier before exiting. Also, the flame you create must start somewhere inside the tube but after the flow rectifier. (Aerospace Major specializing in combustion/propulsion)

 

[Modelworks]

oxy/acetylene cutting torches are used all the time underwater. When you go deeper they switch out the acetylene for hydrogen . The combustion is started with something like a car battery and a welding rod, once the arc is struck the oxygen mix ignites and the battery power can be removed and it will burn as long as oxygen is present.

 

[Selenium_Glow]

As long as the temperature of the flame is high enough to melt/weld the steel/metal under-water, yes, it can be used.

And let us stick to some basics. As long as you have the following 3 conditions, a flame/fire will burn -
1> Temperature high enough to cause combustion
2> the fuel which will burn
3> Enough (gaseous) Oxygen supply.

Basically, underwater, Temperature and oxygen gas would be difficult to get. However, acetylene flame is created inside a closed chamber (where a fuel and oxygen are mixed, then spark ignites the flame) and thrown out of a narrow nozzle. This solves the oxygen gas problem. Now the temperature of an acetylene flame is way to high. so the impact water has on the flame temperature is overall less, and thus, you can melt/weld under water.