Rayleigh Number

Rayleigh number is used in heat transfer in general and free convection calculations in particular. It is equivalent to (Gr.Pr). It is normally defined in one of the following forms :

or

 

Where:

alpha

=

Thermal diffusivity

beta

=

Coefficient of expansion

Cp

=

Heat capacity

delta-T

=

Temperature difference

g

=

Gravitational acceleration

k

=

Thermal Conductivity

L

=

Characteristic length

mu

=

Viscosity

rho

=

Density

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