Numerical simulation of a small-scale biomass boiler

This paper presents a computational fluid dynamic simulation of a domestic pellet boiler. Combustion of the solid fuel in the burner is an important issue when discussing the simulation of this type of system. A simplified method based on a thermal balance was developed in this work to introduce the effects provoked by pellet combustion in the boiler simulation. The model predictions were compared with the experimental measurements, and a good agreement was found. The results of the boiler analysis show that the position of the water tubes, the distribution of the air inlets and the air infiltrations are the key factors leading to the high emission levels present in this type of system.

► Simplified model for biomass combustion was developed.
► Porous zone conditions are used in the bed.
► Model is fully integrated in a commercial CFD code to simulate a small scale pellet boiler.
► Pollutant emissions are well predicted.
► Simulation provides extensive information about the behaviour of the boiler.