Calculating Velocity for Pressure Testing Chamber Design

[costa_1205]

Hey,

I am brand new to this Forum, and I am trying to design a pressure testing chamber. The plan is to test a sample cylinder that is fitted with two needle valves and a quick connect fitting for leaks. I want to do this by pressuring it up to 1800 psi with air and putting it in the chamber which will be filled with water so I can watch for bubbles.

The cylinder is a DOT 3E 1800 and is double sided. All nozles are 1/4". I need to find out the velocity with which a valve or a fitting would hit the sides of the chamber so I can decide of an applicable material.

How can I calculate this?

 

[Achy47]

Hello, welcome to the forum! Designing a pressure testing chamber is a great project. To calculate the velocity of a valve or fitting hitting the sides of the chamber, you will need to use the ideal gas law and Bernoulli's equation.

First, you will need to know the volume of air that will be inside the chamber at 1800 psi. This can be calculated using the ideal gas law, which states that PV = nRT, where P is the pressure, V is the volume, n is the number of moles of gas, R is the ideal gas constant, and T is the temperature. Since you know the pressure and volume, you can rearrange the equation to solve for n, which will give you the number of moles of gas.

Next, you will need to use Bernoulli's equation, which relates the pressure, velocity, and height of a fluid. Since air is a fluid, this equation can be applied to calculate the velocity of the air as it exits the valve or fitting and hits the sides of the chamber. The equation is P + (1/2)ρv^2 + ρgh = constant, where P is the pressure, ρ is the density of the fluid (in this case, air), v is the velocity, g is the acceleration due to gravity, and h is the height.

To calculate the velocity, you will need to know the density of air at the given pressure and temperature. You can find this information in a table or use an online calculator. Once you have the density, you can rearrange the equation to solve for v, which will give you the velocity of the air.

Keep in mind that this calculation will give you the maximum velocity of the air as it exits the valve or fitting. The actual velocity may be lower due to factors such as friction and turbulence. You may also want to consider using a material that can withstand higher velocities to ensure the safety and durability of your pressure testing chamber.

I hope this helps with your project. Good luck!