Methane-fueled porous burner combustion in a domestic boiler: Experimental and numerical study

Using porous media in burner combustion systems helps reduce NOx values by providing more homogeneous flame distribution and lowering local maximum temperature values. Additionally, it ensures less noisy combustion at low flame speeds. However, manufacturing porous media materials is difficult, and experimental studies on these structures are time-consuming and costly. Therefore, examining the effects of burners with different porosity values on combustion is challenging. This study focuses on experimental and numerical investigations of methane-air mixture combustion using a porous burner made of metal fiber material. Emission values for NOx, O2, CO2, and CO components were obtained from experimental studies conducted at different methane gas flow rates (0.436 m3/h, 0.802 m3/h, 1.004 m3/h, and 2.487 m3/h) in a domestic boiler. Additionally, viscous and inertial resistance parameters necessary for the Porous Media Approach used in the numerical model were determined experimentally by analyzing the relationship between pressure drop and velocity in the porous burner. The numerical study of fluid flow and combustion models was carried out using the entire three-dimensional geometry of the boiler components, such as the manifold, burner, heat exchanger, and exhaust. The maximum deviations between the experimental and numerical values for NOx, O2, CO2, and CO were determined to be 4.32 %, 1.31 %, 2.65 %, and 14.46 %, respectively, for a gas flow rate of 2.487 m3/h.