Turbine (Stage)

This is a steam power generation turbine model for the stages between the inlet and outlet. This model inherits the PressureChanger model with the isentropic options. The initialization scheme is the same as the TurbineInletStage model.


from pyomo.environ import ConcreteModel, SolverFactory

from idaes.core import FlowsheetBlock
from idaes.unit_models.power_generation import TurbineStage
from idaes.property_models import iapws95

m = ConcreteModel()
m.fs = FlowsheetBlock(default={"dynamic": False})
m.fs.properties = iapws95.Iapws95ParameterBlock()
m.fs.turb = TurbineStage(default={"property_package": m.fs.properties})
# set inlet


This model adds a variable to the base PressureChanger model to account for mechanical efficiency .

Variable Symbol Index Sets Doc
efficiency_mech \(\eta_{mech}\) None Mechanical Efficiency (accounts for losses in bearings…)

The table below shows important variables inherited from the pressure changer model.

Variable Symbol Index Sets Doc
efficiency_isentropic \(\eta_{isen}\) time Isentropic efficiency
deltaP \(\Delta P\) time Pressure change (\(P_{out} - P_{in}\)) [Pa]
ratioP \(P_{ratio}\) time Ratio of discharge pressure to inlet pressure \(\left(\frac{P_{out}}{P_{in}}\right)\)

\(\eta_{isentropic,t}\) efficiency_isentropic Isentropic assumption only


This model provides two expressions that are not available in the pressure changer model.

Variable Symbol Index Sets Doc
power_thermo \(\dot{w}_{thermo}\) time Turbine stage power output not including mechanical loss [W]
power_shaft \(\dot{w}_{shaft}\) time Turbine stage power output including mechanical loss (bearings…) [W]


There are no additional constraints.


This just calls the initialization routine from PressureChanger, but it is wrapped in a function to ensure the state after initialization is the same as before initialization. The arguments to the initialization method are the same as PressureChanger.

TurbineStage Class

class idaes.unit_models.power_generation.turbine_stage.TurbineStage(*args, **kwargs)

Basic steam turbine model

  • rule (function) – A rule function or None. Default rule calls build().
  • concrete (bool) – If True, make this a toplevel model. Default - False.
  • ctype (str) – Pyomo ctype of the block. Default - “Block”
  • default (dict) –

    Default ProcessBlockData config

    Indicates whether this model will be dynamic or not, default = useDefault. Valid values: { useDefault - get flag from parent (default = False), True - set as a dynamic model, False - set as a steady-state model.}
    Indicates whether holdup terms should be constructed or not. Must be True if dynamic = True, default - False. Valid values: { True - construct holdup terms, False - do not construct holdup terms}
    Indicates what type of mass balance should be constructed, default - MaterialBalanceType.useDefault. Valid values: { MaterialBalanceType.useDefault - refer to property package for default balance type **MaterialBalanceType.none - exclude material balances, MaterialBalanceType.componentPhase - use phase component balances, MaterialBalanceType.componentTotal - use total component balances, MaterialBalanceType.elementTotal - use total element balances, MaterialBalanceType.total - use total material balance.}
    Indicates what type of energy balance should be constructed, default - EnergyBalanceType.useDefault. Valid values: { EnergyBalanceType.useDefault - refer to property package for default balance type **EnergyBalanceType.none - exclude energy balances, EnergyBalanceType.enthalpyTotal - single enthalpy balance for material, EnergyBalanceType.enthalpyPhase - enthalpy balances for each phase, EnergyBalanceType.energyTotal - single energy balance for material, EnergyBalanceType.energyPhase - energy balances for each phase.}
    Indicates what type of momentum balance should be constructed, default - MomentumBalanceType.pressureTotal. Valid values: { MomentumBalanceType.none - exclude momentum balances, MomentumBalanceType.pressureTotal - single pressure balance for material, MomentumBalanceType.pressurePhase - pressure balances for each phase, MomentumBalanceType.momentumTotal - single momentum balance for material, MomentumBalanceType.momentumPhase - momentum balances for each phase.}
    Indicates whether terms for phase equilibrium should be constructed, default = False. Valid values: { True - include phase equilibrium terms False - exclude phase equilibrium terms.}
    Indicates whether this unit should be considered a compressor (True (default), pressure increase) or an expander (False, pressure decrease).
    Flag to set the thermodynamic assumption to use for the unit. - ThermodynamicAssumption.isothermal (default) - ThermodynamicAssumption.isentropic - ThermodynamicAssumption.pump - ThermodynamicAssumption.adiabatic
    Property parameter object used to define property calculations, default - useDefault. Valid values: { useDefault - use default package from parent model or flowsheet, PropertyParameterObject - a PropertyParameterBlock object.}
    A ConfigBlock with arguments to be passed to a property block(s) and used when constructing these, default - None. Valid values: { see property package for documentation.}
  • initialize (dict) – ProcessBlockData config for individual elements. Keys are BlockData indexes and values are dictionaries described under the “default” argument above.
  • idx_map (function) – Function to take the index of a BlockData element and return the index in the initialize dict from which to read arguments. This can be provided to overide the default behavior of matching the BlockData index exactly to the index in initialize.

(TurbineStage) New instance

TurbineStageData Class

class idaes.unit_models.power_generation.turbine_stage.TurbineStageData(component)[source]
initialize(state_args={}, outlvl=6, solver='ipopt', optarg={'max_iter': 30, 'tol': 1e-06})[source]

Initialize the turbine stage model. This deactivates the specialized constraints, then does the isentropic turbine initialization, then reactivates the constraints and solves.

  • state_args (dict) – Initial state for property initialization
  • outlvl – sets output level of initialization routine * 0 = Use default idaes.init logger setting * 1 = Maximum output * 2 = Include solver output * 3 = Return solver state for each step in subroutines * 4 = Return solver state for each step in routine * 5 = Final initialization status and exceptions * 6 = No output
  • solver (str) – Solver to use for initialization
  • optarg (dict) – Solver arguments dictionary