Optimization of Air Flow in the Gasification Chamber of the Gasification Boiler Using the PIV Method

Abstract

The article deals with the optimization of biomass combustion in a small heat source using the optimal distribution of combustion air. Uneven distribution of combustion air was observed during certification tests and in real operation of the used heat source and has an impact on uneven combustion of biomass in the gasification chamber, on increasing emissions and combustion losses. In the first phase of the research, optimization was carried out using CFD simulations, then a transparent model of a real heat source was created, on which the real distribution of combustion air in the gasification chamber was observed using the Particle Image Velocimetry (PIV) method. The results of CFD simulations and the PIV method led to the optimization of the cross-sectional profiles of the four supply channels for gasification air supply. CFD simulations and subsequent PIV measurements on the experimental device were carried out without real combustion, only the air flow in the empty gasification chamber was investigated. This approach was chosen in order to simplify calculations and experiments and on the assumption that with optimal distribution of combustion air in the empty chamber, there will be an optimal even during real combustion. The flow of primary air in the gasification chamber in real operation is influenced by the size and shape of the inserted biomass and its location in the chamber, and this influence is random and difficult to verify. After optimization, the distribution of the primary combustion air in the gasification chamber is uniform and the same amount of air flows into the chamber through the four combustion air inlets.