Rapid valve opening, Adiabatic compression and Oxygen
Rapid valve opening, Adiabatic compression and Oxygen
(OP)
Hello everyone!
I'm currently on a project involving the oxygen compatibility of alloys. We are building a experimental setup which looks will recreate an quasi-adiabatic compression of oxygen onto a piece of metal (and see if it burns, or not).
The setup looks like this:
1000bar vessel ======|>Valve<|===1meter long tube===|Comb. Chamber|
The fast opening valve (fully opened in under 18ms) releases 1000bar pure oxygen into the (silver coated) combustion chamber (atmospheric pressure).
I'm looking for some way to predict velocities, pressures and temperatures inside the apparatus and have some difficulties selecting the models. For example: Should I consider the fast opening valve as a throttling valve? Or should I apply the Fluid Hammer models? How can I find the velocity in the tube leading to the combustion chamber?
Well, in fact, I think I just don't know where to begin with this problem. So any help/insight will be greatly appreciated.
Thank you for your time!
Denis Maloir
I'm currently on a project involving the oxygen compatibility of alloys. We are building a experimental setup which looks will recreate an quasi-adiabatic compression of oxygen onto a piece of metal (and see if it burns, or not).
The setup looks like this:
1000bar vessel ======|>Valve<|===1meter long tube===|Comb. Chamber|
The fast opening valve (fully opened in under 18ms) releases 1000bar pure oxygen into the (silver coated) combustion chamber (atmospheric pressure).
I'm looking for some way to predict velocities, pressures and temperatures inside the apparatus and have some difficulties selecting the models. For example: Should I consider the fast opening valve as a throttling valve? Or should I apply the Fluid Hammer models? How can I find the velocity in the tube leading to the combustion chamber?
Well, in fact, I think I just don't know where to begin with this problem. So any help/insight will be greatly appreciated.
Thank you for your time!
Denis Maloir





RE: Rapid valve opening, Adiabatic compression and Oxygen
Can you achieve that?
RE: Rapid valve opening, Adiabatic compression and Oxygen
Thanks for your reply!
All calculations have been made so that 1000bars could be achieved, yes. We have acquired a high pressure compressor (Howden - Burton-Corblin).
I'm thinking of some kind of water hammer model, but it's usually applied when a valve is suddenly closed. Can it be applied when a tank is suddenly opened on a dead end (closed combustion chamber)?
RE: Rapid valve opening, Adiabatic compression and Oxygen
So to answer your question, apply the first law of thermo to your tube and consider the gas already in the tube doesn't mix very quickly with the incoming gas.