modelSteamTurbine

Information

This model extends SteamTurbineBase by adding the actual performance characteristics:

• Stodola's law with an optional correction due to degradation using Baumann's formula
• Constant isentropic efficiency

The inlet flowrate is also proportional to the partialArc signal if the corresponding connector is wired. In this case, it is assumed that the flow rate is reduced by partial arc admission, not by throttling (i.e., no loss of thermodynamic efficiency occurs). To simulate throttling, insert a valve model before the turbine inlet.

Parameter use_NominalInlet decides if the flow area coefficient is given as a parameter Kt or calculated from nominal values at an operating point. The flow area coefficient Kt, defined at design conditions by Kt = m_flow*sqrt(R*T)/sqrt(p1^2 - p2^2), can be interpreted as effective turbine flow area.

Isentropic efficiency

By default is the isentropic efficiency a parmeter equal to eta_is_nom. But if use_Baumann is true the efficiency is degraded if the fluid enters the two-phase region according to Baumans formula: eta_is = eta_is_nom*(1 - a_Baumann*(1 - x)), where a_Baumann is a parameter and x is the inlet steam quality.

Assumptions

Stodola's law (infinite number of stages)

Constant isentropic efficiency with an optional efficiency degradation using Baumann's formula

No energy or mass storage

No shaft inertia. If needed, connect a Modelica.Mechanics.Rotational.Components.Inertia model to one of the shaft connectors.

References

Cooke, D. H., 'On Prediction of Off-Design Multistage Turbine Pressures by Stodola's Ellipse,'

J. Eng. Gas Turbines Power, Volume 107, Issue 3, pp. 596, 1985.

Parameters

Connectors

Components

Revisions