Flow rate of air in discharging reservoir

In summary, the most effective way to determine the volume flow rate of air discharged through a hose after opening a tank with volume V, pressure P, and temperature T is to use Boyle's Law to calculate the compressed volume of air in the tank. By measuring the pressure at regular intervals and calculating the average flow rate, it is possible to estimate the instantaneous flow rate. Alternatively, looking into flow through an orifice or using compressible flow theory for a crude converging nozzle may also provide helpful insights.
  • #1
rcummings89
19
0
If I have a tank of volume V, pressure P, and temperature T, what is the most effective way to determine the volume flow rate if I were to suddenly allow the air to discharge through a hose?

My first thought was that I could use Boyle's Law to determine the compressed volume of air in the tank:

Vc = Va*(Pc/Pa)

Where Va is the volume of the non-pressurized vessel, and Pa is atmospheric pressure. Then I could measure the pressure at certain time intervals (say, once every 5 seconds) and calculate a new compressed volume. From there I could calculate the average flow rate during that period as

Q = (Va,2 - Va,1) / (t2 - t1)

And if I take the measurements at even shorter time intervals I believe the result should tend toward the instantaneous flow rate.

Am I on the right track with this? Should I be looking at compressible flow theory for a crude converging nozzle instead? Any help or feedback is greatly appreciated in advance!
 
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  • #2
I had a similar question regarding air flow through a nozzle. The best bet is to look into flow through an orifice, also choked flow.
 

Related to Flow rate of air in discharging reservoir

1) What factors affect the flow rate of air in a discharging reservoir?

The flow rate of air in a discharging reservoir can be affected by several factors, including the pressure difference between the reservoir and the surrounding environment, the size and shape of the reservoir opening, and the viscosity of the air.

2) How is the flow rate of air in a discharging reservoir calculated?

The flow rate of air in a discharging reservoir can be calculated using the Bernoulli's equation, which takes into account the pressure difference, density of the air, and the area of the opening. It can also be estimated using empirical formulas based on experimental data.

3) Does the temperature of the air affect the flow rate in a discharging reservoir?

Yes, the temperature of the air can affect the flow rate in a discharging reservoir. As the temperature increases, the density of the air decreases, resulting in a higher flow rate. This is because warmer air can hold more energy, allowing it to escape more quickly through the opening of the reservoir.

4) How does the shape of the reservoir opening impact the flow rate of air?

The shape of the reservoir opening can have a significant impact on the flow rate of air. A larger opening will result in a higher flow rate, while a smaller opening will result in a lower flow rate. Additionally, the shape of the opening can affect the air's velocity and turbulence, which can also impact the flow rate.

5) Can the flow rate of air in a discharging reservoir be controlled?

Yes, the flow rate of air in a discharging reservoir can be controlled by adjusting the pressure difference, changing the size or shape of the opening, or using devices such as valves or regulators. These methods can be used to increase or decrease the flow rate as needed for different applications.

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