# How to Calculate and Solve for Knudsen Diffusion of Moulding Sand | Mass Transfer

The image above represents knudsen diffusion of moulding sand. To calculate knudsen diffusion of moulding sand, three essential parameters are needed and these parameters are Pore Radius (r), Temperature (T)Â andÂ Molecular Weight (M).

### The formula for calculating knudsen diffusion of moulding sand:

DkÂ = 9700râˆš(T/M)

Where:

DkÂ = Knudsen Diffusion of Moulding Sand
T = Temperature
M = Molecular Weight

Let’s solve an example;
Find the knudsen diffusion of moulding sand when the pore radius is 24, the temperature is 18 and the molecular weight is 12.

This implies that;

r = Pore Radius = 24
T = Temperature = 18
M = Molecular Weight = 12

DkÂ = 9700râˆš(T/M)
DkÂ = 9700(24)âˆš(18/12)
So, Dk = 9700(24)âˆš(1.5)
Dk = 9700(24)(1.22)
Dk = 285120.6

Therefore, theÂ knudsen diffusion of moulding sand isÂ 285120.6 cmÂ²/s.

### Calculating the Pore Radius when the Knudsen Diffusion of Moulding Sand, the Temperature and the Molecular Weight are Given

r = Dk / 9700 âˆš(T / M)

Where:

DkÂ = Knudsen Diffusion of Moulding Sand
T = Temperature
M = Molecular Weight

Let’s solve an example;
Find the pore radius when the knudsen diffusion of moulding sand is 20, the temperature is 14 and the molecular weight is 10.

This implies that;

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Dk = Knudsen Diffusion of Moulding Sand = 20
T = Temperature = 14
M = Molecular Weight = 10

r = Dk / 9700 âˆš(T / M)
r = 20 / 9700 âˆš(14 / 10)
Then, r = 20 / 9700 âˆš(1.4)
r = 20 / 11446
r = 0.00174

Therefore, theÂ pore radiusÂ isÂ 0.00174.

### Calculating the Temperature when the Knudsen Diffusion of Moulding Sand, the Pore Radius and the Molecular Weight are Given

T = M x (Dk / 9700r)2

Where:

T = Temperature
DkÂ = Knudsen Diffusion of Moulding Sand
M = Molecular Weight

Let’s solve an example;
Find the temperature when the knudsen diffusion of moulding sand is 2700, the pore radius is 6 and the molecular weight is 14.

This implies that;

Dk = Knudsen Diffusion of Moulding Sand = 2700
r = Pore Radius = 6
M = Molecular Weight = 14

T = M x (Dk / 9700r)2
So, T = 14 x (2700 / 9700(6))2
T = 14 x (2700 / 58200)2
T = 14 x (0.046)2
That is, T = 14 x 0.002116
T = 0.0296

Therefore, theÂ temperatureÂ isÂ 0.0296 s.

### Calculating the Molecular Weight when the Knudsen Diffusion of Moulding Sand, the Temperature and the Pore Radius are Given

M = T / (Dk / 9700r)2

Where:

M = Molecular Weight
DkÂ = Knudsen Diffusion of Moulding Sand
T = Temperature

Let’s solve an example;
Find the molecular weight when the knudsen diffusion of moulding sand is 3000, the pore radius is 8 and the temperature is 4.

This implies that;

Dk = Knudsen Diffusion of Moulding Sand = 3000
r = Pore Radius = 8
T = Temperature = 4

M = T / (Dk / 9700r)2
M = 4 / (3000 / 9700(8))2
Then, M = 4 / (3000 / 77600)2
M = 4 / 0.00148
M = 2702.7

Therefore, theÂ molecular weightÂ isÂ 2702.7 cm.

### How to Calculate Knudsen Diffusion of Moulding Sand Using Nickzom Calculator

Nickzom Calculator â€“Â The Calculator Encyclopedia is capable of calculating the knudsen diffusion of moulding sand.

To get the answer and workings of the knudsen diffusion of moulding sand using the Nickzom Calculator â€“ The Calculator Encyclopedia.Â First, you need to obtain the app.

You can get this app via any of these means:

To get access to theÂ professionalÂ version via web, you need toÂ registerÂ andÂ subscribeÂ forÂ NGN 2,000Â perÂ annumÂ to have utter access to all functionalities.
You can also try theÂ demoÂ version viaÂ https://www.nickzom.org/calculator

Apple (Paid)Â â€“Â https://itunes.apple.com/us/app/nickzom-calculator/id1331162702?mt=8
Once, you have obtained the calculator encyclopedia app, proceed to theÂ Calculator Map,Â then click onÂ Materials and MetallurgicalÂ underÂ Engineering.

Now, Click onÂ Mass TransportÂ underÂ Materials and Metallurgical

Now, Click on Knudsen Diffusion of Moulding Sand underÂ Mass Transport

The screenshot below displays the page or activity to enter your values, to get the answer for the knudsen diffusion of moulding sand according to the respective parameter which is the Pore Radius (r), Temperature (T)Â andÂ Molecular Weight (M).

Now, enter the values appropriately and accordingly for the parameters as required by the Pore Radius (r) is 24, Temperature (T) is 18 and Molecular Weight (M) is 12.

Finally, Click on Calculate

As you can see fromÂ the screenshot above,Â Nickzom Calculatorâ€“ The Calculator Encyclopedia solves for the knudsen diffusion of moulding sand and presents the formula, workings and steps too.