Compressed air discharge calculation for CFM and volume

In summary, the conversation is about determining the cost of air based on pipe size and CFM, with a system that includes lead pipes, one inch pipes, and a vacuum hopper. The speaker is looking for a formula to calculate the volume of air being used, and the expert suggests using Bernoulli's equation to calculate the volume based on pressure and velocity.
  • #1
Dustin WSS
1
0
Ok here is my problem. We have a static value that we use for determining the cost of air based on the pipe size and the CFM used.

What I have is the size of the pipe openings and what my constant static pressure is. The air is being blown into a vacuum.

System details:

Lead pipes is 4 inches. It feeds two one inch pipes that for all intensive purposes is 100 % open. It discharges into a 12ftx12ftx30ft vacuum hopper that maintains a 16 inches of water vacuum in the chamber.

My problem:
I have figured my total discharge area out of the system to be 1.57 square inches of discharge.
My system maintains 90 psi with significant fluctuation. The vacuum system will drop at most .5 inches of water pressure during a hit.
The discharge time is 1.5 seconds.

What I don't know how to do is how to figure out is the volume of air use I have.
 
Physics news on Phys.org
  • #2
I have tried looking for formulas online but I can't seem to find what I am looking for. Any advice or help would be greatly appreciated. Thank you.The formula you are looking for is called Bernoulli's equation. This equation states that the pressure in a system remains constant as long as there is no loss of energy. This means that if you know the pressure at the inlet and outlet of the pipe, you can calculate the volume of air flowing through it. The equation looks like this: Pressure inlet - Pressure outlet = (Air density x Velocity2)/2. You will need to know the air density and velocity of the air in the pipe. Once you have those values, you can calculate the volume of air flowing through the pipe.
 

Related to Compressed air discharge calculation for CFM and volume

1. How do I calculate the CFM of compressed air?

To calculate the CFM (cubic feet per minute) of compressed air, you will need to know the pressure (in PSI) and volume (in cubic feet) of the compressed air. Use the following formula: CFM = (volume in cubic feet x pressure in PSI) / 14.7. For example, if you have a volume of 100 cubic feet and a pressure of 100 PSI, your CFM would be (100 x 100) / 14.7 = 680.27 CFM.

2. What is the difference between CFM and volume when it comes to compressed air?

CFM (cubic feet per minute) is a measurement of the rate at which compressed air is flowing. Volume, on the other hand, is a measurement of the amount of compressed air stored in a tank or container. While CFM indicates how quickly air is being released, volume indicates the total amount of air available.

3. How do I convert CFM to other units of flow, such as liters per minute?

To convert CFM (cubic feet per minute) to liters per minute, you can use the following formula: CFM x 28.32 = liters per minute. For example, if you have a CFM of 200, your flow rate in liters per minute would be 200 x 28.32 = 5664 liters per minute.

4. What factors can affect the accuracy of my compressed air discharge calculation?

Some factors that can affect the accuracy of a compressed air discharge calculation include changes in temperature, humidity, and altitude. These can impact the density of the air and therefore affect the CFM calculation.

5. How can I ensure that my compressed air discharge calculation is accurate?

To ensure accuracy in your compressed air discharge calculation, it is important to measure and record the pressure and volume of the compressed air as accurately as possible. Additionally, taking into account any changes in temperature, humidity, or altitude can also help improve the accuracy of the calculation.

Similar threads

Pressure required for water discharge
    • Electromagnetism
Replies
17
Views
1K
Do Dual Fans Increase Radiator Efficiency More Than a Single Larger Fan?
    • Mechanical Engineering
Replies
6
Views
609
I Compressed air Pushing a Column of Water
    • Classical Physics
Replies
11
Views
1K
Underground pump vault airflow considerations
    • Mechanical Engineering
Replies
15
Views
952
Order of calculations for an air bubble system for dock de-icing
    • General Engineering
Replies
14
Views
2K
Hospital Air Handler, Discharge Airflow vs. Static Pressure
    • Mechanical Engineering
Replies
6
Views
1K
Unstable Static Pressure in Exhaust Duct
    • Mechanical Engineering
Replies
4
Views
1K
Flow rate of air through constriction
    • Aerospace Engineering
Replies
10
Views
805
On-demand steam engine idea
    • Mechanical Engineering
Replies
13
Views
422
I Graduation of air flow inside a vacuum chamber
    • Classical Physics
Replies
4
Views
1K

Hot Threads

Recent Insights

Back
Top