How to Calculate and Solve for Flow Rate | Darcy’s Law | Transport Phenomena

The image above represents flow rate. To calculate flow rate, four essential parameters are needed and these parameters are Permeability (K), Cross-Sectional Area (A), Change in Pressure (ΔP) and Length of Pipe (L).

The formula for calculating flow rate:

Q = KAΔP / L

Where:

Q = Flow Rate | Darcy’s Law
K = Permeability
A = Cross-sectional Area
ΔP = Change in Pressure
L = Length of Pipe

Let’s solve an example;
Find the flow rate when the permeability is 9, the cross-sectional area is 12, the change in pressure is 3 and the length of pipe is 10.

This implies that;

K = Permeability = 9
A = Cross-sectional Area = 12
ΔP = Change in Pressure = 3
L = Length of Pipe = 10

Q = KAΔP / L
Q = (9)(12)(3) / 10
That is, Q = 324 / 10
Q = 32.4

Therefore, the flow rate is 32.4 m³/s.

Calculating the Permeability when the Flow Rate, the Cross-Sectional Area, the Change in Pressure and the Length of Pipe are Given

K = Q x L / AΔP

Where:

K = Permeability
Q = Flow Rate | Darcy’s Law
A = Cross-sectional Area
ΔP = Change in Pressure
L = Length of Pipe

Let’s solve an example;
Find the permeability when the flow rate is 14, the cross-sectional area is 4, the change in pressure is 7 and the length of pipe is 2.

This implies that;

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Q = Flow Rate | Darcy’s Law = 14
A = Cross-sectional Area = 4
ΔP = Change in Pressure = 7
L = Length of Pipe = 2

K = Q x L / AΔP
Then, K = 14 x 2 / (4)(7)
K = 28 / 28
K = 1

Therefore, the permeability is 1.

Read more: How to Calculate and Solve for Permeability | Mass Transfer

Calculating the Cross-Sectional Area when the Flow Rate, the Permeability, the Change in Pressure and the Length of Pipe are Given

A = Q x L / KΔP

Where:

A = Cross-sectional Area
Q = Flow Rate | Darcy’s Law
K = Permeability
ΔP = Change in Pressure
L = Length of Pipe

Let’s solve an example;
Find the cross-sectional area when the flow rate is 10, the permeability is 6, the change in pressure is 5 and the length of pipe is 12.

This implies that;

Q = Flow Rate | Darcy’s Law = 10
K = Permeability = 6
ΔP = Change in Pressure = 5
L = Length of Pipe = 12

A = Q x L / KΔP
So, A = 10 x 12 / (6)(5)
A = 120 / 30
A = 4

Therefore, the cross-sectional area is 4.

Calculating the Change in Pressure when the Flow Rate, the Permeability, the Cross-Sectional Area and the Length of Pipe are Given

ΔP = Q x L / KA

Where:

ΔP = Change in Pressure
Q = Flow Rate | Darcy’s Law
K = Permeability
A = Cross-sectional Area
L = Length of Pipe

Let’s solve an example;
Find the change in pressure when the flow rate is 24, the permeability is 4, the cross-sectional area is 6 and the length of pipe is 2.

This implies that;

Q = Flow Rate | Darcy’s Law = 24
K = Permeability = 4
A = Cross-sectional Area = 6
L = Length of Pipe = 2

ΔP = Q x L / KA
ΔP = 24 x 2 / (4)(6)
So, ΔP = 48 / 24
ΔP = 2

Therefore, the change in pressure is 2.

Read more: How to Calculate and Solve for Entrance Velocity | Darcy’s Law | Water Budget

Calculating the Length of Pipe when the Flow Rate, the Permeability, the Cross-Sectional Area and the Change in Pressure are Given

L = KAΔP / Q

Where:

L = Length of Pipe
Q = Flow Rate | Darcy’s Law
K = Permeability
A = Cross-sectional Area
ΔP = Change in Pressure

Let’s solve an example;
Find the length of pipe when the flow rate is 10, the permeability is 8, the cross-sectional area is 3 and the change in pressure is 5.

This implies that;

Q = Flow Rate | Darcy’s Law = 10
K = Permeability = 8
A = Cross-sectional Area = 3
ΔP = Change in Pressure = 5

L = KAΔP / Q
L = (8)(3)(5) / 10
That is, L = 120 / 10
L = 12

Therefore, the length of pipe is 12.

How to Calculate Flow Rate | Darcy’s Law Using Nickzom Calculator

Nickzom Calculator – The Calculator Encyclopedia is capable of calculating the flow rate.

To get the answer and workings of the flow rate using the Nickzom Calculator – The Calculator Encyclopedia. First, you need to obtain the app.

You can get this app via any of these means:

Web – https://www.nickzom.org/calculator-plus

To get access to the professional version via web, you need to register and subscribe to have utter access to all functionalities.
You can also try the demo version via https://www.nickzom.org/calculator

Android (Paid) – https://play.google.com/store/apps/details?id=org.nickzom.nickzomcalculator
Android (Free) – https://play.google.com/store/apps/details?id=com.nickzom.nickzomcalculator

Apple (Paid) – https://itunes.apple.com/us/app/nickzom-calculator/id1331162702?mt=8
Once, you have obtained the calculator encyclopedia app, proceed to the Calculator Map, then click on Materials and Metallurgical under Engineering.

Now, Click on Transport Phenomena under Materials and Metallurgical

Now, Click on Flow Rate under Transport Phenomena

The screenshot below displays the page or activity to enter your values, to get the answer for the flow rate according to the respective parameter which is the Permeability (K), Cross-Sectional Area (A), Change in Pressure (ΔP) and Length of Pipe (L).

How to Calculate and Solve for Flow Rate | Darcy's Law | Transport Phenomena

Now, enter the values appropriately and accordingly for the parameters as required by the Permeability (K) is 9, Cross-Sectional Area (A) is 12, Change in Pressure (ΔP) is 3 and Length of Pipe (L) is 10.

How to Calculate and Solve for Flow Rate | Darcy's Law | Transport Phenomena

Finally, Click on Calculate

How to Calculate and Solve for Flow Rate | Darcy's Law | Transport Phenomena

As you can see from the screenshot above, Nickzom Calculator– The Calculator Encyclopedia solves for the flow rate and presents the formula, workings and steps too.

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