# Pipe Flow Calculator, Flow Rate Calculation, Formula With Example

### Pipe Flow Calculator:

Use this pipe flow calculator to analyze the properties of water flowing in a gravity feed system. You only need to know the diameter of the pipe, the material it is made of, its length and drop in height. We use the Hazen-Williams equation for you to calculates the resulting velocity and discharge.

• Get pipe material type, pipe diameter, length and drop values.
• Find the hydraulic radius value i.e. diameter divided by 4.
• Calculate the slope of the power line, which is the pipe length divided by the drop.
• Get the area of ​​circular tube.
• Change the values ​​in the formulas.
• Perform mathematical operations to check the discharge and flow rate of a pipe.

When the flow of water in a pipe is due to gravity, it is called gravity flow of water. We can calculate the flow velocity of water using Hazen-Williams equation.

Hazen-Williams equation is valid only for water. The formula is dashed.

### Hazen Williams Equation:

Hazen Williams equation is the water flow velocity in the pipe V(ft/s) in feet per second is equal to the is conversion factor k(ft) in feet and multiply the roughness coefficient c(ft) in feet and multiply  the  hydraulic radius R(ft)0.63 and multiply the slope of the energy line s(ft)0.54 in feet.Hence the Hazen Williams equation can be written as

V(ft/s)=k(ft)*c(ft)*R(ft)0.63 *s(ft)0.54

V=is the water flow velocity in the pipe (m/s is for the metric system,ft is for the imperial system)

C=is the roughness coefficient

S=is the slope of the energy line

K=is conversion factor (k=0.849 for the metric system k=1.318f or the imperial system)

Hydraulic radius is defined as the ratio of area and perimeter of the pipe.As the pipe is in a circular shape

The slope of the energy line is obtained by dividing the pipe length by the drop

The formula to get the flow discharge Q is as follows

Q=A*V

### Example:1

Calculate the velocity and discharge of a copper pipe having 0.6ft in diameter.The pipe is 25 ft long and the difference in height between the starting and endpoints of the pipe is 4 ft.

Given that

Diameter of pipe d=0.6ft

Pipe length =25ft

Drop=4ft

Cross-sectional area A=π*r2=3.14*0.32

=0.2826ft2

Perimeter of the pipe p=2*π*r

=2*3.14*0.3

=1.884ft

=0.2826/1.884

=0.15ft

Slop s=drop/length of pipe

=4/25=0.16

As the pipe material is copper, the roughness coefficient c=140

Hazen Williams equation for velocity v=K*c*R0.63*s0.54

Substitute the values k=1.318 ft constant value

V=1.318*140(0.15)0.64 *(0.16)0.54

V=20.368ft/s

Flow discharge Q=A*v

=0.2826*20.368=5.7562 ft3/s

Therefore, the water flow rate is 20.368ft/s and flow discharge is 5.7562 ft3/s

### Example:2

Calculate the velocity and discharge of a copper pipe having 0.5ft in diameter.The pipe is 15 ft long and the difference in height between the starting and endpoints of the pipe is 5 ft.

Given that

Diameter of pipe d=0.5ft

Pipe length =15ft

Drop=5ft

Cross-sectional area A=π*r2=3.14*0.252

=0.1963ft2

Perimeter of the pipe p=2*π*r

=2*3.14*0.25

=1.57ft

=0.1963/1.57

=0.125ft

Slop s=drop/length of pipe

=5/15=0.33

As the pipe material is copper, the roughness coefficient c=140

Hazen Williams equation for velocity v=K*c*R0.63*s0.54

Substitute the values k=1.318 ft constant value

V=1.318*140(0.125)0.64 *(0.33)0.54

V=26.795ft/s

Flow discharge Q=A*v

=0.1963*26.795=5.25 ft3/s

Therefore, the water flow rate is 26.795 ft/s and flow discharge is 5.25 ft3/s