Controlling fluid Flow under pressure?

In summary, the conversation discusses the problem of stepping down pressure and fixing the flow at 10 gallons per minute in a 100 gallon tank constantly filled and pressurized by a pump to 1000psi. The solution proposed is to have a pipe connecting the tank to a hydraulic motor, but the required diameter and length of the pipe is unknown. The relationship between pressure and flow in fluid dynamics is mentioned, and pressure drop calculators may be used to determine the required pipe dimensions. However, if the flow rate through the motor is adjusted, the pressure may also change. It is suggested to also consider controlling the pump that pressurizes the tank.
  • #1
Frangelo
18
0
this is not a homework problem, its a practical problem for a system I'm working on, but its looks pretty much like a homework problem so posting here.

Homework Statement



Assume a 100 gallon tank is filled with water, constantly filled and pressurized by a pump to 1000psi

Assume a hydraulic powered motor which operates with intake required at 300psi, flow of 10 gallons per minute.

Can the problem of stepping down the pressure and fixing the flow at 10 gallons per minute be solved by having a pipe connecting the tank to the motor of a given diameter, or a valve at the tank end, where the pipe is of fixed diameter, say 1"? The tank and the and motor are in close proximity, the pipe can be set to the length required.

How generally to determine the diameter required? Is the length of the pipe relevant? Or is there some other step required to fix both the pressure and flow between the tank and motor?

Homework Equations



No sure.

The Attempt at a Solution



Flummoxed.

I assume there is a relationship between pressure in the pipe and resistance to flow provided by the hydraulic motor. I know I can adjust raise pressure in the pipe by opening the value at tank end and/or using a smaller diameter pipe, but I'm not sure how/if its possible to control both pressure and flow independently as I'd guess they are related as in electricity flow, viz V=IR which in this case I'd guess would be something like pressure = flow x resistance, or Flow = Pressure/Resistance or something like that, but not really sure of units and the like.
 
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  • #2
Fluid dynamics isn't my area of expertise but there are pressure drop calculators around on the web. They might allow you to calculate the length and diameter of pipe required to drop 700psi at 10gpm. However if you then load up the hydraulic motor so that the flow rate through it is lower then 10gpm the pressure will rise. For example if you stall the motor so there is zero flow you might see 1000psi at the motor (no pressure loss in the pipe).
 
  • #3
PS Perhaps look at controlling the pump that's pressurising the tank?
 

1. How does pressure affect fluid flow?

Pressure is a key factor in controlling fluid flow. When pressure is increased, the molecules in the fluid are pushed closer together, increasing their kinetic energy and causing them to flow faster. On the other hand, decreasing pressure will result in slower fluid flow.

2. What is the relationship between fluid viscosity and flow under pressure?

Viscosity, or the thickness of a fluid, also plays a role in fluid flow under pressure. Higher viscosity fluids, such as honey, will flow slower under pressure compared to lower viscosity fluids like water. This is because the molecules in high viscosity fluids have a stronger attraction to each other, making it more difficult for them to move past each other.

3. How is fluid flow under pressure controlled in industrial applications?

In industrial applications, fluid flow under pressure is often controlled using valves, pumps, and other devices. These tools can regulate the pressure and flow rate of the fluid to achieve the desired result. Additionally, pipelines and tubing can be designed to withstand certain levels of pressure to ensure safe and efficient flow.

4. What factors can cause changes in fluid flow under pressure?

Aside from pressure and viscosity, there are several other factors that can affect fluid flow under pressure. These include the size and shape of the container or pipeline, the type of fluid being used, and the temperature. Additionally, external forces such as gravity or friction can also impact fluid flow.

5. How can fluid flow under pressure be optimized?

To optimize fluid flow under pressure, it is important to consider all the factors involved, including pressure, viscosity, and external forces. Properly designed and maintained equipment, as well as regular monitoring and adjustments, can help achieve optimal flow rates. Additionally, selecting the right type of fluid for the specific application can also improve efficiency and control of fluid flow under pressure.

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