Steam Turbine Calculator watch tutorial view guide

Calculates the energy generated or steam outlet conditions for a steam turbine.


Solve for:

Inlet Steam

Pressure* psig
* °C btu/lbm kJ/kg/K

Turbine Properties

Selected Turbine Property
Mass Flow * klb/hr
Isentropic Efficiency * %
Generator Efficiency * %
Power Out * kW

Outlet Steam

Pressure* psig
* °C btu/lbm kJ/kg/K
* Required [reset]
Allowed Range / Limits
Minimum
Maximum
**Example: Solve for Outlet Properties

Examples: Mouse Over
Solve for Outlet Properties Solve for Isentropic Efficiency



Calculation Details and Assumptions below

Inlet Steam

Mass Flow26.5 klb/hr
Pressure103.1 psig Sp. Enthalpy1,258.8 btu/lbm
Temperature239.8 °C Sp. Entropy6.990 kJ/kg/K
PhaseGas Energy Flow35,195
pipe
Arrowpipe
Arrow
Steam Turbine

Outlet Steam

Mass Flow26.5 klb/hr
Pressure78.4 psig Sp. Enthalpy1,245.2 btu/lbm
Temperature221.9 °C Sp. Entropy7.033 kJ/kg/K
PhaseGas Energy Flow34,814
Isentropic Efficiency60.3 %
Energy Out381
Generator Efficiency80.8 %
Power Out85.4 kW


Calculation Details

Step 1: Determine Inlet Properties

Using the Steam Property Calculator, properties are determined using Inlet Pressure and the selected second parameter (Temperature, Specific Enthalpy, Specific Entropy, or Quality). The Specific Enthalpy is then multiplied by the Mass Flow to get the Energy Flow:
  • Inlet Energy Flow = Specific Enthalpy * Mass Flow
    [ Inlet Energy Flow = 35,195 = 1,258.8 btu/lbm * 26.5 klb/hr ]

Step 2: Calculate Ideal Outlet Properties (Inlet Entropy equals Outlet Entropy)

Step 3: If solve for 'Isentropic Efficiency', Determine Outlet Properties

Using the outlet specific enthalpy, calculate the isentropic efficiency:
  • Isentropic Efficiency = (Inlet Specific Enthalpy - Outlet Specific Enthalpy) / (Inlet Specific Enthalpy - IDEAL Outlet Specific Enthalpy)

Step 3: If solve for 'Outlet Properties', Determine Outlet Specific Enthalpy

  1. Isentropic Efficiency = (Inlet Specific Enthalpy - Outlet Specific Enthalpy) / (Inlet Specific Enthalpy - IDEAL Outlet Specific Enthalpy)
  2. Isentropic Efficiency * (Inlet Specific Enthalpy - IDEAL Outlet Specific Enthalpy) = (Inlet Specific Enthalpy - Outlet Specific Enthalpy)
  3. Outlet Specific Enthalpy = Inlet Specific Enthalpy - Isentropic Efficiency * (Inlet Specific Enthalpy - IDEAL Outlet Specific Enthalpy)
    [Outlet Specific Enthalpy = 1,245.2 btu/lbm = 1,258.8 btu/lbm - 60.30 % * (1,258.8 btu/lbm - 1,236.2 btu/lbm)]
Using the outlet specific enthalpy, calculate the outlet properties:

Step 4: Calculate Steam Turbine Energy Out and Generation (Power Out)

  • Energy Out = (Inlet Specific Enthalpy - Outlet Specific Enthalpy) * Mass Flow
    [Energy Out = 381 = (1,258.8 btu/lbm - 1,245.2 btu/lbm) * 26.5 klb/hr]
  • Power Out = Energy Out * Generator Efficiency
    [Power Out = 85.4 kW = 381 * 80.80 %]

Assumptions

  • Inlet Mass Flows equal Outlet Mass Flow.