top

Nusselt Number Calculator

To find the Nusselt number, enter the values of characteristic length, thermal conductivity, and the heat coefficient in the Nusselt number calculator.

W/m2-K
m
W/m-K

Is This Tool Helpful?

     

This calculator helps to find different parameters that are involved in the Nusselt number equation. Users can choose between 4 values to calculate any one value. 

What is the Nusselt Number?

It is a dimensionless number that is a ratio of transfer of heat between the convective (to the fluid) to the conductive (within the fluid). 

The name is given after a German scientist Wilhelm Nusselt. It is a function of Reynolds and Prandtl numbers.

Nusselt Number Formula

The formula of Nusselt number:

Nu = h * k / L

In this equation:

Nu = Nusselt number

h = Convection heat transfer coefficient 

k = conductivity coefficient 

L = characteristic length  

Equations related to Nusselt number are: 

For convection:

h = Nu * k / L

For conduction:

k = h * L / Nu

How to calculate the Nusselt number?

Example:

Calculate the Nusselt number if:

Convection heat transfer coefficient = h = 15 W/m2-K 

Conductivity coefficient = k = 8 W/m-k

Characteristic length = L = 7 m

Solution:

Step 1: Write the formula:

Nu = h * k / L

Step 2: Put the values.

Nu = 15 * 8 / 7

Nu = 17.1.43

X