Characterization of premixed flame blow-off downstream a multi-perforated burner

The shift from the current energy system towards a less carbon intensive one requires modifications in the energy vectors used and in the technology of energy consuming devices. Gaseous fuels are forecasted to cover a significant portion of the worldwide energy demand in the next decades, although the fuel composition will be different from the today’s one due to the changes in the energy system dynamics, related to the security of energy supply and the reduction of overall CO2 emissions. Especially in the domestic sector, gaseous fuels will be widely used to power devices with premixed combustion technology. The advantages of premixed devices in comparison to non-premixed ones are higher energy efficiency and lower pollutant emission. Despite the industrial maturity of premixed appliances, the design process is extremely complex for the aspects related to combustion. In fact, the combustion dynamics are not fully understood, and the burner design is mostly based on empirical observations and on industrial experience. A few companies in the world are specialised in managing the design of premixed burners. The aim of this study is to generate knowledge on the premixed burner design process, with the focus on the widely used multi-perforated burners. A test rig for performing experimental activities on flat premixed burners has been designed, and a series of experimental data on blow-off behaviour of premixed flames downstream these burners has been collected. Elementary multi-slot burners, with significantly different open areas, have been compared in terms of fuel/air ratios at blow-off. The results achieved have been interpreted and explained basing on the principles of combustion theory. These investigations could enhance both the subsequent appliance-oriented developments and the research on fundamentals.