In physics, the Péclet number is a dimensionless number relating the forced convection of a system to its heat conduction. It is equivalent to the product of the Reynolds number with the Prandtl number.

There are various definitions of the Péclet number. The most typical are as follows:

Pe = Re * Pr (equivalent to above)

With:

• α - Thermal diffusivity
• λ - Thermal conductivity
• ρ - Density
• c_p - Heat capacity
• l - Characteristic length
• t - Characteristic time
• v - Velocity

It named after Jean Claude Eugene Peclet (1793-1857).