Combined CFD, material and system level analyses - Case Naantali power plant

This paper discusses the use of mathematical models in solving engineering problems. Undoubtedly there is a need for closer co-operation and co-use of different tools to enhance solving industrial engineering problems. This is shown through a recent case study, where thermal behaviour of evaporator pipes in a power plant was analysed. The main tool is the study was Apros, which is a software for dynamic modelling and simulation of industrial processes, and related automation and electrical systems. Additionally, the work was supported by CFD and thermal stress calculations. A model of a once-through evaporator of a coal power plant was developed, and used to analyse thermal behaviour of the evaporator tubes. Proper knowledge of the boundary conditions at the flue gas side were required. This information was obtained from the existing CFD results on the same evaporator. The main interest in simulations was the differences in pipe temperatures between two alternative control strategies of the evaporator: level control mode, and superheating mode. The simulation results were temperatures, and further interpretation was needed to draw the conclusions of the risk for the material. So yet another mathematical approach was needed to answer the original questions. The modelling part of the case is briefly described, the most interesting results are shown, and the combined use of modelling is discussed.