Application of a Porous Cell Model to the Simulation of Tube Bundles in Convective Parts of Industrial Utility Boilers

摘要

The vast majority of computational calculations of industrial utility boilers focuses on the combustion part of the boiler. The heat transfer in tube bundles is often neglected despite its significant influence on the steam generation process. Because of the huge demand of computational power even for boiler calculations without convective heat exchangers, a detailed consideration of tube bundles is impossible. An appropriate way to take into account such tube bundles is to use a porous cell model. In this work a porous cell model is presented. It has been developed and applied within the 3D-combustion simulation code AIOLOS to improve the knowledge about the heat transfer and aerodynamic behaviour of the flue gas flow in the convective parts of large scale industrial utility boilers. An experimental test facility was used to compare the computational results with measurements of temperature and velocity distribution influenced by tube bundles. Advantages and limitations of the porous cell model are discussed. Proposals are made to improve the presented model. The applicability of the porous cell model is demonstrated for the combined modelling of the convective and radiative section of a 600 MW_e industrial scale boiler.