APPLICATION OF A DOMAIN DECOMPOSITION TECHNIQUE TO THE MATHEMATICAL-MODELING OF A UTILITY BOILER

Domain decomposition techniques are very effective for flow simulation, especially in domains where geometrical length scales of different orders of magnitude are present. In this work a zonal method is applied to the mathematical modelling of a power station boiler of the Portuguese Electricity Utility. The mathematical model is based on the numerical solution of the partial differential equations governing conservation of mass, momentum and energy. The zonal method is presented and the conservative treatment of the interfaces is described in detail. Emphasis is placed on the evaluation of the zonal method. The results show that the influence of the zonal method on the convergence rate of the solution algorithm is negligible. The zonal method does not influence the accuracy of the predicted results and there is continuity of the dependent variables across the interfaces. A significant reduction in CPU time is feasible due to a better distribution of grid nodes and consequent reduction in the total number of grid nodes required.