An in-house built code incorporated into CFD model for the simulation of boiler's convection section

Abstract

This work presents an in-house built code and its incorporation into an ANSYS Fluent® Computational Fluid Dynamics (CFD) model for the simulation of the convection section of a boiler without needing numerous thermodynamic or experimental data, sophisticated numerical grids or assumptions that decrease the validity of the model. This model has been applied in a recently retrofitted lignite-fired boiler's convection section. Due to the lack of experimental data after the retrofit, the investigation follows a parametric approach, assuming three different distributions of the ash fouling thickness. The three distributions have been suitably selected to fit the CFD results of the in-house built model in the full-load case with: 1) the CFD results using the Macro Heat Exchanger Model provided by ANSYS Fluent®, 2) the results of an ASPEN Plus® process model and 3) experimental data before the retrofit actions. The only necessary input data for the in-house built code are the inlet temperature, the average pressure and the mass flow rate of the working medium for each heat exchanger. Based on the results, it can be concluded that the in-house built model is robust, consistent and validated for the simulation of a boiler's convection section.