How to calculate the Fourier number of a material

Calculation for a Fourier Number

• 1

  Determine the thickness of the material through which the heat is transferred or diffused if the value is not already known. Thickness can be determined with a ruler, calipers, or a measuring tape in most cases.

• 2

  Determine the thermal diffusivity of the material from commonly available charts. Multiply the thermal diffusivity value per inch or centimeter by the actual thickness of the material.

• 3

  Square the material thickness.

• 4

  Multiply the thermal diffusivity by the time period the heat conduction was observed. If the thermal diffusion was not manually recorded, use one minute.

• 5

  Divide the value from step three with the squared value of the material thickness. The answer is the Fourier number for the material.

Calculation for a Modified Fourier Number

• 6

  Determine the thickness of the flow through which the heat must pass. This can be the width of an air curtain or water wall.

• 7

  Determine the thermal diffusivity of the material from commonly available charts. Multiply the thermal diffusivity value per inch or centimeter by the actual thickness of the material. For a water wall, use the thermal diffusivity of water. For an air curtain, use the thermal diffusivity value for air.

• 8

  Square the value of the material flow's thickness.

• 9

  Multiply the thermal diffusivity by the time period the heat conduction was observed. If the thermal diffusion was not manually recorded, use one minute.

• 10

  Divide the value from step three with the square of the material thickness. The result is the modified Fourier number for the material flow.