efficiency calculation using reference temperature
 

Hi, guys:

I am calculating the total to total efficiency of turbine blade. In my simulation reference temperature is 25 C; reference Pressure is 1atm; reference Enthalpy is 0 [J/kg].
When I use equation: eta = (Tt, inlet – Tt,outlet) / (Tt, inlet – Tt,outlet,isen)
Where Tt,outlet,isen = (Pt,outlet/Pt,inlet)^( (gamma-1)/gamma )* Tt, inlet

Do I need to minus reference temperature and reference pressure from the value I obtained from CFX post? I.E. should the right form of efficiency is following:
eta = (Tt, inlet – Tt,outlet) / (Tt, inlet - Tref – Tt,outlet,isen)
where Tt,outlet,isen = ( (Pt,outlet-Pref)/(Pt,inlet-Pref) )^( (gamma-1)/gamma )* (Tt, inlet – Tref)

Thank you very much!