Understanding Pressure Regulators: Static & Dynamic Pressure

• K41
In summary, the manometer before the pressure regulator reads 10 Bar, indicating a barely moving flow. If the manometer is after the pressure regulator, it would read zero bar. If the valve is closed, the reading on the manometer would be 10 Bar.
K41
I'm struggling to understand how pressure regulators work (and total pressure in general). I currently have an open system. So the pressurized air goes through the regulator and afterwards (after going through some further pipe), enters the atmosphere. I will assume the hydrostatic variations in pressure are negligible. The gas is incompressible and at room temperature.

I placed a manometer gauge before the pressure regulator. It measures the static pressure. It reads 10 Bar. This is where I start to get confused:

1) Does the reading of 10 Bar on the manometer before the regulator mean that the flow is barely moving? Or better worded, would I need a pitot tube the determine the total pressure, subtract the two to find the dynamic pressure and find the velocity..

2) Can anyone explain how the regulator works specifically in terms of static and dynamic pressure? I've seen plenty of explanations but they just refer to "pressure" and I need something in terms of static and dynamic to make things clearer for me. I'm thinking when the regulator is "fully open", does that mean the dynamic pressure is lowest (large area opening therefore lower velocity) and so the static pressure is highest?

3) If I placed the same manometer AFTER the pressure regulator, would it read zero bar?

4) If the manometer after the regulator had some small value of pressure, would that mean there is something downstream of the regulator (i.e. between the regulator and the atmosphere) that was causing some "resistance". Is this "resistance" restricting the dynamic pressure and therefore increasing the static pressure or is it dissipating the energy into heat and therefore reducing the total pressure? In the latter, why would the pressure gauge still read an increase in static pressure?

5) If I had a valve, placed after the regulator, which was closed, what would the reading on the manometer be? I originally thought it would read 10 Bar if the regulator was fully open. But if the regulator was half open, what would it read?

6) Just a general thing. When people refer to "pressure drop", do they mean that the total pressure has reduced? How does this effect the pressure gradient in the Navier-Stokes eqns?

Last edited:
Yes i also need more details on it...

What is a pressure regulator?

A pressure regulator is a device used to control and maintain the pressure of a fluid or gas within a system. It works by reducing the incoming pressure to a desired level and maintaining it at a constant value, even as the upstream pressure changes.

How does a pressure regulator work?

Pressure regulators typically consist of a spring-loaded valve that opens and closes in response to changes in pressure. When the upstream pressure increases, the valve opens to allow excess pressure to escape, thus maintaining a constant downstream pressure.

What is static pressure and why is it important to understand?

Static pressure refers to the pressure of a fluid or gas when it is not in motion. It is important to understand because it is the initial pressure that a pressure regulator must reduce and regulate.

What is dynamic pressure and how does it differ from static pressure?

Dynamic pressure refers to the pressure of a fluid or gas when it is in motion. It differs from static pressure because it takes into account the speed and direction of the fluid or gas. Dynamic pressure can fluctuate and affect the performance of a pressure regulator.

How do I choose the right pressure regulator for my system?

There are several factors to consider when choosing a pressure regulator, such as the type of fluid or gas being regulated, the desired pressure range, and the flow rate. It is important to consult with a professional and carefully consider the specific needs of your system before selecting a pressure regulator.

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