Flow through pipes and throttling valves .NEED HELP

In summary, the conversation discusses a real-life problem involving gravity flow from a water collection tank to a lower elevation. The desired outcome is to deliver the same flow rate with reduced pressure using a throttling valve or nozzle. The equations for flow rate and pressure are mentioned, and there is some uncertainty about how the throttle valve will affect the flow rate and pressure. Using a nozzle is suggested as a possible solution.
  • #1
JPEng
2
0
Flow through pipes and throttling valves...NEED HELP!

I need some help with a real-life problem

I have an open topped water collection tank at elevation. The water is distributed by gravity flow from the tank via a pipe to a lower elevation. At the point of delivery, the pressure head is 18psi. However I need to deliver the water at the same flow rate that is filling the tank but at a reduced pressure of 7 psi. Can i use a throttling valve to achieve this?
 
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  • #2


not sure if this will help but flow rate is calculated as: Q=VA

so the flow rate Q is equal to the velocity of the water times the area of the head.



if the opening is round the area, A, is computed as:3.1415/4 * D^2


Also the equation for pressure is: P = F/A so in your case it would work out to

A* 7psi= F

Hope this helps you in some way.
 
  • #3


Thanks bro...although i understand flow rate calculations, I still can't relate it to the proposed throttle valve...would the flow remain constant after passing the throttle? Would there be a pressure drop across the throttle?
 
  • #4


using a reducer or nozzle will lower the pressure head and flow rate will remain constant...
Throttle valve as far as i know, is a flow control valve, so will reduce the flow rate...Im not sure though.
 
  • #5


As R Power says, use a nozzle to reduce pressure.
 

Related to Flow through pipes and throttling valves .NEED HELP

1. What is flow through pipes and throttling valves?

Flow through pipes and throttling valves is the movement of fluid (such as water, gas, or oil) through a system of pipes and valves that control the flow rate. Throttling valves are used to regulate the flow rate by adjusting the size of the opening through which the fluid passes.

2. How is the flow rate affected by the size of the pipe?

The flow rate through a pipe is directly proportional to the size of the pipe. In other words, as the size of the pipe increases, the flow rate also increases. This is because a larger pipe allows for more fluid to pass through at a given time, resulting in a higher flow rate.

3. What factors affect the flow rate through pipes and throttling valves?

The flow rate through pipes and throttling valves can be affected by several factors, including the size and shape of the pipe, the type of fluid being transported, the pressure and temperature of the fluid, and the design and condition of the valves.

4. How does the Bernoulli's principle apply to flow through pipes and throttling valves?

The Bernoulli's principle states that as the velocity of a fluid increases, the pressure decreases. This principle applies to flow through pipes and throttling valves as well, as the fluid's velocity can increase or decrease depending on the size and shape of the pipe and the design of the valves. This can result in changes in pressure and flow rate within the system.

5. How can I calculate the flow rate through a pipe?

The flow rate through a pipe can be calculated using the continuity equation, which states that the flow rate (Q) is equal to the cross-sectional area of the pipe (A) multiplied by the velocity of the fluid (v). In other words, Q = A x v. The flow rate can also be determined by measuring the pressure and flow rate at different points along the pipe and using the Bernoulli's equation.

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