Stefan number

{{short description|Ratio of sensible heat to latent heat}}

{{Refimprove|date=September 2014}}

The Stefan number{{IPAc-en|ˈ|s|t|ɛ|f|æ|n}} (St or Ste) is defined as the ratio of sensible heat to latent heat. It is given by the formula

$\backslash mathrm\{Ste\}\; =\; \backslash frac\{c\_p\; \backslash Delta\; T\}\{L\},$

where

• c_p is the specific heat,
• c_p is the specific heat of solid phase in the freezing process while c_p is the specific heat of liquid phase in the melting process.
• ∆T is the temperature difference between phases,
• L is the latent heat of melting.

It is a dimensionless parameter that is useful in analyzing a Stefan problem. The parameter was developed from Josef Stefan's calculations of the rate of phase change of water into ice on the polar ice caps and coined by G.S.H. Lock in 1969.Lock, G. S. H. (1969). On the use of asymptotic solutions to plane ice -water problems The problems origination is fully described by Vuik{{cite web |last1=Vuik |first1=C |date=1993 |title=Some historical notes about the Stefan problem |url=http://ta.twi.tudelft.nl/users/vuik/papers/DUT-TWI-93-07.pdf |publisher=Delft, University of Technology}} and further commentary on its place in Josef Stefan's larger career can be found in Crepeau, J. (2007). Josef stefan: His life and legacy in the thermal sciences. Experimental Thermal and Fluid Science, 31(7), 795-803. doi:https://doi.org/10.1016/j.expthermflusci.2006.08.005

Same number exist for vapor to liquid phase change, Nombre de Jakob.