How you can calculate the CFM for 1 TR ?

We cant extactly say the CFM for1 Ton. But as per Thumb rule, 

For centralized air conditioning system, I tr=400 CFM

For non centralized conditioning sysytem, I tr=300CFM.

Well goof question most of manufacturers consider400/300 CFM per nominal TR you cannot consider that when your are working on different ambient conditions, since your CFM/TR will change. 

For Fresh air application you can consider as a Thumb Role (100 to150) CFM/RT  

Actually one ton of refrigeration =12,000 BTU/hr. When it comes to relating this to air quantities, the basic equation is: Q (btu/hr) =1.08 (constant for air at standard conditions)*density correction factor*cfm*delta T 400 cfm per ton is a manufacturers nominal standard, or rule of thumb. It should get you in the ballpark, but is not exact.

each TR =400 CFM  thumb rule      200 Sq.ft =1 TR .....150 to200 Sq.ft =1TR 

evrey is having there own formula regarding cfm calculation . which means no body knows exactly what cfm is and how it is calculated'