Pressure change and area ratio help

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Discussion Overview

The discussion revolves around the dynamics of pressure release from a container, specifically focusing on the escape velocity of air when released into another container with an obstruction. Participants explore variables affecting this process, including container sizes and nozzle designs, in the context of building a spud gun operating at 120 psi.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant inquires about the escape velocity of air when released from a container at 120 psi and asks for relevant variables.
  • Another participant identifies the size of the containers and the orifice as critical factors in determining the escape velocity.
  • A different participant seeks advice on optimal barrel to air container ratios for maximizing velocity in a spud gun, emphasizing the importance of operating at 120 psi.
  • One participant mentions that without a converging-diverging (C-D) nozzle, the valve on the tank may choke, limiting maximum velocity.
  • Another participant acknowledges the concept of choked flow and notes that achieving a supersonic airstream may not be beneficial if the focus is solely on mass flow.

Areas of Agreement / Disagreement

Participants express varying views on the importance of nozzle design and flow characteristics, indicating that there is no consensus on the optimal approach for maximizing velocity in the context of the spud gun.

Contextual Notes

Discussion includes assumptions about flow dynamics, the impact of nozzle design on performance, and the specific conditions under which the pressure is released. There are unresolved aspects regarding the relationship between mass flow and velocity in this context.

Who May Find This Useful

Individuals interested in fluid dynamics, engineering applications related to pressure systems, and hobbyists building pneumatic devices may find this discussion relevant.

sokolomi
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so if you put about 120 psi in a container and then instanly release it into another with something blocking the way, how fast would that escape, what are the variables in this
 
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do guys know any good barrel to air container ratios or anything i should know befor i go building a spud gun because i want maximum velocity out of it with like 120 psi
 
Unless you can make a C-D nozzle, you'll probably end up choking the valve on the tank and that will set your max velocity.
 
I forgot about choked flow, but in any case, a C-D nozzle still involves choked flow...(i know you know that). If he only cares about mass flow, getting a supersonic airstream doesn't actually do anything for him.
 

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