Combustion of Natural Gas at the Surface of a High-Porosity Metal Matrix

Comparative studies of the combustion of natural gas in burner devices with flat and 3D matrices made of high-porosity metal foam were performed. It was demonstrated that stable combustion in infrared mode can be realized at specific combustion powers of up to 30-40 W/cm(2). For the 3D matrices, the specific combustion power per unit area of the external cross section was as high as 160 W/cm(2). For the combustion of near-stoichiometric mixtures at the maximum specific combustion power, the concentrations of nitrogen oxides and carbon monoxide were within 16-18 and 40-60 ppm, respectively, decreasing approximately proportionally with the specific combustion power. When the combustible mixture was diluted with air to an air-to-fuel equivalence ratio of above 1.5, the concentration of pollutants decreased to less than 5 ppm. A model was developed which made it possible to calculate the temperatures of the flame front and of the working and back surfaces of the matrices. The calculation results were found to be in close agreement with the experimental data.