Optimization and performance verification of a radial double-layer porous media burner: Integrated numerical-experimental approach

To enhance radiative efficiency and extend the stable combustion range of porous media burners, this study proposes a novel radial double-layer porous media burner. Using integrated numerical simulations combined with the response surface method, the dimensional parameters of the gas distribution chamber holes (α, d, and s) were optimized. The optimal configuration (α = 22.19°, d = 1.09 mm, s = 6.83 mm) achieved a velocity uniformity index of 0.84, with a pressure loss coefficient below 31.36. Parametric analysis revealed that increasing the preheating layer thickness (Lp) enhances heat reflux but elevates pressure drops, necessitating a trade-off between thermal feedback capacity and flow resistance. Increasing combustion layer thickness (Lc) extends the stable combustion upper limit and improves the radiation output efficiency. Under the configuration with Lp = 15 mm and Lc = 20 mm, stable submerged combustion can be achieved at inlet velocities ranging from 1 to 5 m/s (φ = 0.65), with a radiation efficiency of 15.25 %–24.13 %. Experimental results indicate that the burner exhibits superior temperature uniformity (σT < 57.89 °C) and low emissions (NOx < 37.93 mg/m3) under various operating conditions. Furthermore, it maintains stable submerged combustion in a CO2 diluted atmosphere with concentrations as high as 30 %, demonstrating outstanding fuel adaptability. This study provides options for the development of radial porous media radiant burners.