Question

Please discuss 4 major regions for phase change heat transfer

Answer 1

In metallurgical studies various properties of the material can be find out from phase diagram because in addition of temperature to the materials or engineering materials phase is changed at specific temperatures which is entirely depends on the properties of materials.

And phase diagrams can give best knowledge about various properties and phases that coexist at equilibrium.For best understanding about regions of phase change heat transfer consider one solid substance which is heated upto it becomes gas. So in 1st region phase of substance is solid. When heat is continuously added temperature is increases and so melting of solid substance is begins at the phase change temperature. Now in 2nd region heat is then transferred to second phase i.e. solid to liquid phase without changing temperature. Under further heating substance change into entirely liquid state in region 3. Now in simillar way heat is added again continuously to melted region unless and untill it becomes change of phase saturated vapour condition.Beyond which further heating sensible heating of the is place i.e region 5.

From above discussion we can conclude that when the phase change heat transfer it is latent heat ie temperature remains constant and when phase is not changing heat added is sensible heat ie temperature is increased.  

All the regions are given below