To obtain the characteristic time we dimensionlessed the governing equation and present it with a group of constants that determine value of of the characteristic time by set it to unity. Lets define

the characteristic path of the heat transfer from the die inner surface

to the cooling channels

subscript

B boiling temperature of cooling liquid

M liquid metal melting temperature

With these definitions equation () is transformed to

which leads into estimate of the characteristic time as

Note the characteristic time is not effected by the definition of the . discussion about the typical estimates and how to calculate it

copyright Dec , 2006

The pdf version is also available here