Enter the diameter of the pipe and the angle of the filled pipe into the calculator to determine the flow rate. This calculator assumes a constant velocity of 1 foot per second.
Partial Pipe Flow Formula
The following formula is used to calculate the flow rate in a partially filled pipe.
Q = (r^2 / 2) * (θ - sin(θ))
Variables:
- Q is the flow rate (cubic feet per second)
- r is the radius of the pipe (inches)
- θ is the angle of the filled pipe (radians)
To calculate the flow rate in a partially filled pipe, use the radius of the pipe to find the cross-sectional area of the flow using the angle of the filled pipe. This formula assumes a constant velocity of 1 foot per second across the cross-sectional area.
What is Partial Pipe Flow?
Partial pipe flow occurs when a pipe is not completely full of fluid, and the flow rate is determined by the cross-sectional area of the fluid in the pipe. This situation is common in sewer systems and open channel flows where the pipe is not under pressure and the fluid is subject to gravity. The flow rate is influenced by the shape of the pipe, the roughness of the pipe’s interior, and the slope of the pipe.
How to Calculate Partial Pipe Flow?
The following steps outline how to calculate the Partial Pipe Flow.
- First, determine the diameter of the pipe (D) in inches and convert it to radius (r) by dividing by 2.
- Next, determine the angle of the filled pipe (θ) in degrees and convert it to radians.
- Next, gather the formula from above = Q = (r^2 / 2) * (θ – sin(θ)).
- Finally, calculate the flow rate (Q) in cubic feet per second.
- After inserting the variables and calculating the result, check your answer with the calculator above.
Example Problem :
Use the following variables as an example problem to test your knowledge.
pipe diameter (D) = 24 inches
angle of filled pipe (θ) = 90 degrees
