modelInversion

Information

Extension of the Exercise6SteamPowerPlant of a steam power plant by a mixing preheater. See TUMExercisesThermodynamicCycles.Exercise7MixingPreheater for problem description..

This example uses the InverseBlockConstraints model resulting in implicit nonlinear equations. These equations require suitable start values to be solvable.

Problem description

A small increase in the efficiency of a stationary steam power plant (compared to example 6) is achieved by installing a mixing preheater. Saturated liquid water at state 1 (50.0 mbar, 32.90 °C) is pumped by the reversible adiabatic feedwater lowPressurePump to 10.0 bar.

In the isobaric, externally adiabatic mixingPreheater, a portion of the mass flow (state 7) from the process steam extracted from the turbine is mixed with the water from state 2. This results in a feedwater temperature of T3 = 130 degC. The reversible adiabatic feedwater highPressurePump then raises the water pressure to 20.0 bar.

In the isobaric heater, the water is heated, vaporized and superheated (288 MW) to 540 degC.

In the steam turbine (isentropic efficiency eta_is = 0.889), after the first turbine stage (highPressureTurbineStage, 10.0 bar), a portion of the steam (state 7) is extracted and fed to the mixingPreheater. The remaining steam in the turbine is further expanded (lowPressureTurbineStage, 50.0 mbar), condensed in the isobaric condenser and returned to the lowPressurePump, closing the cycle.

Components

Contents

Name	Description
Medium

Revisions

• 2026, by Raphael Gebhart (raphael.gebhart@dlr.de):
  Initial version.