Please Help Me Find the Flow Rate
Please Help Me Find the Flow Rate
(OP)
Hey everyone,
I have a fluid system of water coming from a pressure source. Then there is a converging nozzle, which I have calculated the resistance coefficient using Crane's Manual and it has an outlet to the atmosphere.
I have tried to simplify the system. The full system is a pressure source, converging nozzle which has outlet into original diameter at converging nozzle inlet followed by hose to outlet to atmosphere. (this is like a fire hose system - slightly different for my actual application)
The pressure of the pressure source is my independent variable, I am doing a sweep in excel. So if it helps for simplicity, you can assume the pressure is 100 psi.
How do I calculate the flow rate (in GPM)? Do I need to take away the outlet of the system?
Currently I am thinking using:
hL = [k(v)^2]/(2g)
ΔP = (ρ*hL)/144
then what for q??
Or I am thinking q = K*A*(2*144*g*ΔP/ρ)
but then what is ΔP?? is it the pressure drop across the converging nozzle or is it the pressure drop from the inlet to outlet at atmospheric?
I have a fluid system of water coming from a pressure source. Then there is a converging nozzle, which I have calculated the resistance coefficient using Crane's Manual and it has an outlet to the atmosphere.
I have tried to simplify the system. The full system is a pressure source, converging nozzle which has outlet into original diameter at converging nozzle inlet followed by hose to outlet to atmosphere. (this is like a fire hose system - slightly different for my actual application)
The pressure of the pressure source is my independent variable, I am doing a sweep in excel. So if it helps for simplicity, you can assume the pressure is 100 psi.
How do I calculate the flow rate (in GPM)? Do I need to take away the outlet of the system?
Currently I am thinking using:
hL = [k(v)^2]/(2g)
ΔP = (ρ*hL)/144
then what for q??
Or I am thinking q = K*A*(2*144*g*ΔP/ρ)
but then what is ΔP?? is it the pressure drop across the converging nozzle or is it the pressure drop from the inlet to outlet at atmospheric?





RE: Please Help Me Find the Flow Rate
Wanted to include a picture of the system:
RE: Please Help Me Find the Flow Rate
Mike McCann, PE, SE (WA)
RE: Please Help Me Find the Flow Rate
RE: Please Help Me Find the Flow Rate
Maybe this can help clarify the problem:
http://www.physicsforums.com/showthread.php?t=7640...
RE: Please Help Me Find the Flow Rate
RE: Please Help Me Find the Flow Rate
Here is the attachment of the excel I'm working on. As you can see I have a table of variable inputs to calculate K values for varying nozzle designs. Then I have a sweep of pressures vs. the nozzle designs. What I am trying to complete is the Q (gpm) calculations for the given P and K values (based on nozzle design). The idea is that if we are given a system, we can use this table to find an appropriate nozzle design that will satisfy the job. It's not in the picture or the post, but this is a water jet eductor educting dry powder fire suppression agent.
RE: Please Help Me Find the Flow Rate
Katmar Software - AioFlo Pipe Hydraulics
http://katmarsoftware.com
"An undefined problem has an infinite number of solutions"