Calculating Compressed Air Propulsion: Methods and Formulas for Model Torpedoes

[Gepard]

Hi,

I'm currently designing a model torpedo and plan to use compressed air for it's propulsion and am working out if it's feasible.

At the moment I'm trying to calculate how long it takes for X volume of compressed air at Y pressure to leave (IE return to atmospheric pressure) through a hole or vent of Z diameter. I've had a Google but I'm not quite sure how to phrase it but so far the best way I can think of it is to break it down into groups of milliseconds and then use the Venturi Effect to give me a rough idea but it seems a little crude.

Anyone care to suggest a better method? I'm presuming there is some 'magical formula' that I'm not quite getting.

Cheers,

Michael

 

[FredGarvin]

Take a look at Milton Beychok's website here:

http://www.air-dispersion.com/feature2.html

Even though it is labeled for accidental release, it is applicable for the pressurized release to atmosphere of a compressed gas. It's worth your time to read through.

 

[ravenprp]

Hello Michael,

Calculating the propulsion of a model torpedo using compressed air can be a complex task. However, there are some methods and formulas that can help you determine the feasibility of your design. One approach is to use the ideal gas law, which states that the pressure, temperature, and volume of a gas are related by the equation PV=nRT, where P is pressure, V is volume, n is the number of moles of gas, R is the gas constant, and T is temperature. This equation can help you determine the volume of compressed air needed to achieve a certain pressure and how long it will take to release through a specific diameter hole or vent.

Another method is to use the Bernoulli's equation, which takes into account the fluid flow and the Venturi effect you mentioned. This equation can help you determine the velocity of the compressed air as it exits the hole or vent, which can then be used to calculate the time it takes for the air to reach atmospheric pressure.

I recommend consulting with a fluid dynamics expert or researching more in-depth on these equations to get a more accurate estimation. Good luck with your design!