# Péclet Number Calculation

**Formula:** `Pe = v * L / D`

The Péclet number (Pe) is a dimensionless number relevant in the study of transport phenomena in fluid flows. It is commonly used in the fields of chemical engineering and heat transfer. The Péclet number is defined as the product of the velocity of the flow (v) and its characteristic length (L) divided by the molecular diffusivity (D). It is a measure of the relative importance of advection to diffusion.
In this formula, ** v** is the velocity of the fluid with respect to the object,

**is the characteristic length scale, and**

*L***is the molecular diffusivity. For heat transfer problems, D can be replaced with thermal diffusivity, and for mass transfer, it would be the mass diffusivity.**

*D*Practical applications of the Péclet number include predicting heat transfer in fluids, understanding material diffusion, and in designing chemical reactors.

Tags: Fluid Mechanics, Clet Number, Dimensionless Number, Transport Phenomena