Optimization of a premixed cylindrical burner for low pollutant emission

• The mixing uniformity of methane closely relates to low burning emissions.
• Optimal exit position and diameter of nozzle are obtained with high methane mixing.
• Low emissions of optimal burner are experimentally validated.

A premixed cylindrical burner is numerically and experimentally investigated to realize low pollutant emission. The geometrical parameters of nozzle exit position and nozzle diameter are optimized by using a validated Computational Fluid Dynamics model. The natural gas-air mixing in the mix chamber indicates that the uniformity of methane concentration increases with the increase of distance from ejector outlet. It is found that the nozzle exit position at −3.0 mm improves the overall performance of premixed cylindrical burner, when nozzle diameter is not less than 1.6 mm. The emission characteristics of nitrogen oxides and carbon monoxide are also examined by experimental approach. It is found that load factor has a great influence on nitrogen oxides and carbon monoxide emissions, but the effect is gradually disappeared when air coefficient is not less than 1.4. When nozzle exit position is −3.0 mm, nozzle diameter is not less than 1.6 mm and air coefficient is not less than 1.4, the emissions of nitrogen oxides and carbon monoxide are less than 20 ppm and 50 ppm, respectively.