EVALUATION OF A THREE-DIMENSIONAL MODEL FOR THE PREDICTION OF HEAT TRANSFER IN POWER STATION BOILERS

摘要

This paper reports an evaluation of a full three-dimensional mathematical model of a power station boiler with emphasis on the heat transfer phenomena. The model is based on the numerical solution of the equations governing conservation of mass, momentum and energy and transport equations of scalar quantities. The radiative heat transfer is modelled using the discrete transfer method. The model was applied to a power station boiler of the Portuguese Electricity Utility where an experimental study was recently carried out. Measurements of gas temperature, species concentrations and incident heat fluxes to the walls were compared with the predictions for standard operating conditions, partial load operation and low excess air conditions. Comparison of the results with the measurements has shown that in general a good agreement was achieved, but in some cases only qualitative agreement was found. More detailed measurements would be needed to allow a better evaluation of the model and to identify the sources of discrepancy. Nevertheless, the model proved to be a useful tool for the analysis of the heat transfer in utility boilers.