EXPERIMENTAL INVESTIGATION OF TWO STAGED WOOD-CHIP COMBUSTION IN A SMALL-SCALE BOILER AND DEVELOPMENT OF A FAST SOLVING NUMERICAL SIMULATION APPROACH

摘要

Computational Fluid Dynamics (CFD) is an upcoming technique for both optimization and as a part of the design process of biomass combustion systems. Decreased industrial development times require fast and accurate simulation tools. Therefore, it is important to gain a satisfactory trade-off between computational effort and physical level of detail. The current work deals with experimental and numerical investigations of two-staged wood-chip combustion in a semi-commercial wood-chip boiler. In the experimental part, significant influences on the primary combustion product composition (gaseous species, water and tar) as well as the particulate matter emissions were identified. On the basis of the experiments a time efficient and dependably CFD model for small-scale biomass combustion was developed. In order to highlight the advantages of the actual approach, additional simulations with different gas-phase combustion models were performed. The simulation results were analyzed and compared to each other and with results from experiments in which the main operation parameters were equal to the numerical investigations. The validation process revealed that the presented approach can deliver highly accurate simulation results. Thus it is a perfectly suitable method for fast and reliable future industry research and development.