Steam flow calculation
Steam flow calculation
(OP)
I have a calculation based on enthalpy so as to attemperate steam to a turbine. The calculation has the following formula which I can´t understand.
Flow = m x(Enthalpy (HPT)- Enthalpy (CRH) /Enthalpy (CRH) - 764.8) kg/s
Enthalpy (HPT) = High pressure turbine. Enthalpy calculated from presssure and temperature before HP turbine
Enthalpy (CRH) = Enthalpy calculated from pressure and temperature before reheater, to where the HP steam is bypassed.
m = mass flow according to Steam valve opening, using pressure and temperature before valve.
Find logic attached.
The part I dont get is (Enthalpy (HPT)- Enthalpy (CRH) /Enthalpy (CRH) - 764.8).
Can someone explain.
thanks
Flow = m x(Enthalpy (HPT)- Enthalpy (CRH) /Enthalpy (CRH) - 764.8) kg/s
Enthalpy (HPT) = High pressure turbine. Enthalpy calculated from presssure and temperature before HP turbine
Enthalpy (CRH) = Enthalpy calculated from pressure and temperature before reheater, to where the HP steam is bypassed.
m = mass flow according to Steam valve opening, using pressure and temperature before valve.
Find logic attached.
The part I dont get is (Enthalpy (HPT)- Enthalpy (CRH) /Enthalpy (CRH) - 764.8).
Can someone explain.
thanks





RE: Steam flow calculation
You have stream IN with enthalpy equal to enthalpy (HPT).
You have stream OUT with enthalpy equal to enthalpy (CRH)
The value 764.8, I presume expressed in kJ/kg, should be the specific water enthalpy at saturation pressure (9.08 barg) or saturation temperature (180.344 °C) before reheater. What works here is the enthalpy of evaporation, which is the difference between the specific enthalpy of steam and the specific enthalpy of water.
RE: Steam flow calculation
RE: Steam flow calculation
RE: Steam flow calculation
RE: Steam flow calculation
(Whpt+Ws)*Hcrh = Whpt*Hhpt+Ws*Hs
where Hs= spray water enthalpy