Experimental and analytical study of a porous media burner with passive air entrainment.

摘要

A porous media burner is demonstrated that utilizes passive entrainment of air, heat of combustion and upstream mixing to form a combustible, preheated and premixed fuel/air mixture at the burner outlet, and therefore requires no auxiliary resources beyond a source of compressed fuel gas for operation. Potential applications for a burner with these features include an improved design for flaring gas that is produced during oil and gas production, and a heat source for cooking in rural areas. The porous media burner design presented in this study incorporates an eductor, swirl mixing chamber, and porous media bed in order to achieve premixed fuel before combustion. A range of fuel flow rates to the burner was tested in this study, and the effect on air entrainment, and therefore equivalence ratio, was examined. A wide range of stable operating conditions shows a large turndown ratio of the burner. The surface-stabilized flame exhibited flame speeds above the adiabatic flame speed, producing flame speed ratios greater than unity and indicating effective heat recirculation by the porous media. Species measurements of methane, carbon monoxide and carbon dioxide are presented and show product compositions near equilibrium and a high extent of fuel conversion efficiency. An analytical model of the burner that accounts for burner geometry and operating conditions to predict equivalence ratio is presented and compared with the experimental results. The analytical model compares favorably with the experimental results and can guide future burner development.