modelSteamTurbineBase
Steam turbine
Information
This base model contains the basic interface, parameters and definitions for steam turbine models. It lacks the actual performance characteristics, i.e. two more equations to determine the flow rate and the efficiency.
This model does not include any shaft inertia by itself; if that is needed, connect a Modelica.Mechanics.Rotational.Inertia model to one of the shaft connectors.
Modelling options
The following options are available to calculate the enthalpy of the outgoing steam:
- explicitIsentropicEnthalpy = true: the isentropic enthalpy h_out_iso is calculated by the Medium.isentropicEnthalpy function.
- explicitIsentropicEnthalpy = false: the isentropic enthalpy is given equating the specific entropy of the inlet steam steam_in and of a fictional steam state steam_iso, which has the same pressure of the outgoing steam, both computed with the function Medium.specificEntropy.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| SI.Pressure | p_crit | Medium.fluidConstants[1].criticalPressure | Medium critical pressure |
| Assumptions | |||
| Boolean | allowFlowReversal | system.allowFlowReversal | = true to allow flow reversal, false restricts to design direction |
| Advanced | |||
| Integer | nUnits | 1 | Number of turbine units, e.g., high pressure and low pressure |
| Dynamics | energyDynamics | Dynamics.SteadyState | =true to use turbine dynamics |
| SI.Time[nUnits] | taus | fill(1, nUnits) | Characteristic time constant of each unit |
| SIadd.NonDim[nUnits] | Q_fracs | fill(1/nUnits, nUnits) | Fraction of power provided per unit |
| Initialization | |||
| SI.Power[nUnits] | Q_units_start | fill(m_flow_start*(h_a_start - h_b_start)/nUnits, nUnits) | Initial power output per unit |
| Efficiency | |||
| Real | eta_mech | 1.0 | Mechanical efficiency |
| Initialization › Start Value: Absolute Pressure | |||
| Medium.AbsolutePressure | p_a_start | system.p_start | Pressure at port a |
| Medium.AbsolutePressure | p_b_start | p_a_start | Pressure at port b |
| Initialization › Start Value: Temperature | |||
| Boolean | use_T_start | true | Use T_start if true, otherwise h_start |
| Medium.Temperature | T_a_start | system.T_start | Temperature at port a |
| Medium.Temperature | T_b_start | T_a_start | Temperature at port b |
| Initialization › Start Value: Specific Enthalpy | |||
| Medium.SpecificEnthalpy | h_a_start | Medium.specificEnthalpy_pTX(p_a_start, T_a_start, X_start) | Specific enthalpy at port a |
| Medium.SpecificEnthalpy | h_b_start | Medium.isentropicEnthalpy(p_b_start, Medium.setState_phX(p_a_start, h_a_start, X_start)) | Specific enthalpy at port b |
| Initialization › Start Value: Mass Fractions | |||
| Medium.MassFraction[Medium.nX] | X_start | Medium.X_default | Mass fractions m_i/m |
| Initialization › Start Value: Trace Substances | |||
| Medium.ExtraProperty[Medium.nC] | C_start | fill(0, Medium.nC) | Trace substances |
| Initialization › Start Value: Mass Flow Rate | |||
| Medium.MassFlowRate | m_flow_start | system.m_flow_start | Mass flow rate |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| TRANSFORM.Fluid.Interfaces.FluidPort_Flow | portHP | high pressure port | |
| TRANSFORM.Fluid.Interfaces.FluidPort_Flow | portLP | low pressure port | |
| Modelica.Mechanics.Rotational.Interfaces.Flange_a | shaft_a | ||
| Modelica.Mechanics.Rotational.Interfaces.Flange_b | shaft_b | ||
| Modelica.Blocks.Interfaces.RealInput | partialArc |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Fluid.System | system | System properties | |
| Eta_wetSteam | eta_wetSteam | ||
| Medium.ThermodynamicState | state_a | ||
| Medium.ThermodynamicState | state_b | ||
| Real | p_ratio | p_out/p_in pressure ratio | |
| SI.Angle | phi | Shaft rotation angle | |
| SI.Torque | tau | Net torque acting on the turbine | |
| SI.AngularVelocity | omega | Shaft angular velocity | |
| SI.MassFlowRate | m_flow | Mass flow rate | |
| Medium.SpecificEnthalpy | h_in | Inlet enthalpy | |
| Medium.SpecificEnthalpy | h_out | Outlet enthalpy | |
| Medium.SpecificEnthalpy | h_is | Isentropic outlet enthalpy | |
| Medium.AbsolutePressure | p_in | Inlet pressure | |
| Medium.AbsolutePressure | p_out | Outlet pressure | |
| SI.Power | Q_mech | Total mechanical power | |
| SI.Power[nUnits] | Q_units | Mechanical power per unit | |
| SI.Power[nUnits] | Qbs | Power balance | |
| SI.Efficiency | eta_is | Isentropic efficiency | |
| Medium.SaturationProperties | sat_in | Medium.setSat_p(p_in) | Properties of saturated fluid at inlet |
| Medium.SaturationProperties | sat_out | Medium.setSat_p(p_out) | Properties of saturated fluid at outlet |
| Medium.ThermodynamicState | bubble_in | Medium.setBubbleState(sat_in, 1) | Bubble point state at inlet |
| Medium.ThermodynamicState | dew_in | Medium.setDewState(sat_in, 1) | Dew point state at inlet |
| Medium.ThermodynamicState | bubble_out | Medium.setBubbleState(sat_out, 1) | Bubble point state at outlet |
| Medium.ThermodynamicState | dew_out | Medium.setDewState(sat_out, 1) | Dew point state at outlet |
| SI.SpecificEnthalpy | h_fsat_in | bubble_in.h | Saturated liquid specific enthalpy at inlet |
| SI.SpecificEnthalpy | h_gsat_in | dew_in.h | Saturated vapor specific enthalpy at inlet |
| SI.SpecificEnthalpy | h_fsat_out | bubble_out.h | Saturated liquid specific enthalpy at outlet |
| SI.SpecificEnthalpy | h_gsat_out | dew_out.h | Saturated vapor specific enthalpy at outlet |
| Units.NonDim | x_th_in | Inlet thermodynamic quality | |
| Units.NonDim | x_abs_in | Inlet absolute mass quality | |
| Units.NonDim | x_th_out | Outlet thermodynamic quality | |
| Units.NonDim | x_abs_out | Outlet absolute mass quality |
Contents
| Name | Description |
|---|---|
 Medium | |
| Eta_wetSteam |
Revisions
- 20 Apr 2005
by Francesco Casella:
First release. - 5 Oct 2011
by Francesco Casella:
Small changes in alias variables.