Login    Register
User Information
We are a free and open
community, all are welcome.
Click here to Register
Who is online

In total there are 52 users online :: 5 registered, 0 hidden and 47 guests

Most users ever online was 155 on Mon Aug 15, 2016 1:40 am

Registered users: Bing [Bot], Exabot [Bot], Google [Bot], Google Adsense [Bot], Yahoo [Bot] based on users active over the past 5 minutes

The Team
Global Moderators
global_moderators.png CS

Pressure Instrumentation

A place to ask general spud cannon related questions.
  • Author

Unread postAuthor: jimmy101 » Tue Oct 01, 2013 6:16 pm

What Ramses said.

The problem is that in a combustion chamber (1) the gas temperature is very high but the amount of heat is pretty low and (2) gases loose heat to their container very quickly.

You chamber might have a gram or so of gases heated up to 2000C but the gun itself is much more massive than that. You can do the full heat conservation calculation but you can get the idea if you assume that both the gun and the gases have the same heat capacity. Heat capacity is how much heat energy it takes to heat (or cool) a given mass by one degree. One gram of gases at 2000C versus 1000 g gun at 22C. Final temperature of the gun and gases is about 24C, which you can't even detect with your hand. And, that happens very quickly.

If you put a check valve between the chamber and a gauge what are you actually capturing? Combustion gases (that are hot and will cool) or air in the lines (which is heated by compression but will also quickly cool) or some of both? How fast is the check valve? Can it open/close fast enough?

It is easy to detect that the pressure spiked. Measuring the actual peak is a lot trickier.
  • 0


Lieutenant General
Lieutenant General
Posts: 3124
Joined: Wed Mar 28, 2007 9:48 am
Location: Greenwood, Indiana
Country: United States (us)
Reputation: 7


Return to General Spud Cannon Related

Who is online

Registered users: Bing [Bot], Exabot [Bot], Google [Bot], Google Adsense [Bot], Yahoo [Bot]

Reputation System ©'