Pressure Added to a Flow Loop by a Pump?

In summary, the conversation is about setting up a flow loop for a university experiment on the Bernoulli equation. The loop has a pump and pressure transducers, and the speaker is trying to calculate the pressures at different points using a specific formula. They had to reverse the pump's position to get accurate pressure readings, and are now unsure how it affects the overall pressure. The speaker is seeking help on how to match their recorded pressures with calculations, and whether they should consider turbulent frictional pressure drops in their calculations.
  • #1
shauntur
3
0
Hi there,

I have set up a flow loop for a uni experiment that will teach other students about the bernoulli equation. The loop will use a few working section that will increase and decrease pressure due to diameter, velocity and height changes.

I first set-up my loop with the pump at the end, pulling the water through the system so that i wouldn't have to worry about any discharge pressures. However i had to reverse this to get the pressure readings in the range of the pressure transducers.

I have been calculating the pressures at a point using:
p = density*gravity*height - 0.5*density*(velocity^2)
where height is the distance below the water level to the transducer.
I want to be able match the recorded pressures with some calculations, But now i have the pump at the start i am unsure how this adds to the pressures?
I am able to calculate the flow rate, as the difference p2-p1 will cancel the constant out. If i use the pump curve to find the pressure head at this flow rate, is this the discharge pressure that i can add to the equation above to obtain the actual pressure at each point.

Any help would be appreciated,
Thanks

Shaun
 
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  • #2
shauntur said:
Hi there,

I have set up a flow loop for a uni experiment that will teach other students about the bernoulli equation. The loop will use a few working section that will increase and decrease pressure due to diameter, velocity and height changes.

I first set-up my loop with the pump at the end, pulling the water through the system so that i wouldn't have to worry about any discharge pressures. However i had to reverse this to get the pressure readings in the range of the pressure transducers.

I have been calculating the pressures at a point using:
p = density*gravity*height - 0.5*density*(velocity^2)
where height is the distance below the water level to the transducer.
I want to be able match the recorded pressures with some calculations, But now i have the pump at the start i am unsure how this adds to the pressures?
I am able to calculate the flow rate, as the difference p2-p1 will cancel the constant out. If i use the pump curve to find the pressure head at this flow rate, is this the discharge pressure that i can add to the equation above to obtain the actual pressure at each point.

Any help would be appreciated,
Thanks

Shaun
Yes. The head is the outlet pressure minus the inlet pressure divided by ρg. Don't forget to include the turbulent frictional pressure drops, if these are significant (which they probably are).

Chet
 

What is a flow loop and how does it work?

A flow loop is a closed system used to simulate and study fluid flow in various industrial, mechanical, and chemical processes. It consists of a pump, piping, valves, and instruments that create a continuous flow of fluid. The fluid can be water, oil, or any other liquid or gas. The pump provides the force to circulate the fluid through the loop, and the flow rate and pressure can be controlled by adjusting the valves.

What is the role of a pump in a flow loop?

A pump is an essential component of a flow loop as it is responsible for adding pressure to the fluid and maintaining a constant flow rate. It creates the driving force to circulate the fluid through the loop and enables the study of different flow conditions and their effects on the system. Without a pump, the fluid would not be able to flow, and the loop would not be functional.

How does a pump add pressure to a flow loop?

A pump adds pressure to a flow loop by creating a difference in pressure between its inlet and outlet. When the fluid enters the pump at a lower pressure, it is forced through the pump's impeller, which increases its velocity. As the fluid exits the pump at a higher velocity, it converts into pressure energy. This pressure energy is then used to overcome any resistance in the loop and maintain a constant flow rate.

What factors affect the pressure added by a pump in a flow loop?

The pressure added by a pump in a flow loop can be affected by several factors, including the pump's speed, the diameter and length of the piping, the type of fluid being pumped, and the resistance of the system. Additionally, the pump's efficiency and the type of impeller used can also impact the pressure added to the flow loop.

How can the pressure added by a pump in a flow loop be measured and monitored?

The pressure added by a pump in a flow loop can be measured and monitored using pressure gauges or sensors placed at different points in the loop. These instruments can provide real-time data on the pressure at various locations, allowing for adjustments to be made to maintain a desired pressure and flow rate. Additionally, flow meters can also be used to measure the flow rate and indirectly infer the pressure added by the pump.

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