Grätz Number
Grätz number is proportional to { (thermal capacity) / (convective heat transfer) } and is used in heat transfer in general and convection in laminar flow calculations in particular. It is equivalent to {(L/d) / (Re.Pr)} or {(L/d) / Pe}. It is normally defined in one of the following forms :
or
or
or
Where: |
alpha |
= |
Thermal diffusivity |
Cp |
= |
Heat capacity |
d |
= |
Diameter |
G |
= |
Mass velocity |
k |
= |
Thermal Conductivity |
L |
= |
Length |
m |
= |
Mass flowrate |
rho |
= |
Density |
V |
= |
Velocity |
|
