Lewis Number Calculator

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Lewis Number (Le) = α / Dc

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Thermal Diffusivity (α) :
Mass Diffusivity (Dc) :

Result :

What is Lewis's Number?

Lewis number is a comparison of the relative size of the thermal boundary layer and concentration boundary layer. Meaning it will tell how the fluid will behave if we have conjugate mass and thermal transfer.

Lewis number is often described as “Le” or “nle”. It is a ratio between thermal and mass diffusivity. It has no dimension meaning it is unitless.

Such numbers can provide us with a convenient way to characterize problems when there are several coupled transport mechanisms.

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