Simulation Models of Steam Drums Based on the Heat Transfer Equations

The aim of this paper is the description of two simulation models that have been realized in the Matlab/Simulink environment in order to study the heat transfer in the metal and insulation parts of steam drums belonging to heat recovery steam generators located in combined cycle power plants. Both simulators derive from a finite differences model based on the discretization of the Fourier’s heat conduction equation but are characterized by a different Simulink structure; their main output is the temperature and the thermo-mechanical stress distribution inside the metal of a steam drum. Owing to their short runtimes and flexibility, the two simulators can be linked with the real-time dynamic simulation model of the combined cycle power plant and can be used to evaluate the plant life consumption due to transient operating conditions which determine high thermo-mechanical stresses in metal components. Then the paper reports on some simulation results concerning the models validation phase and the analysis of typical transient operating conditions of a combined cycle power plant.