Liquid Fuel Combustion Using Heat Recirculation Through Annular Porous Media

A counter-flow annular heat recirculating burner was designed for lean prevaporized, premixed combustion. Prior to entering the combustor, the reactants are passed through a porous media-filled preheating annulus surrounding the combustor. Kerosene is dripped by gravity onto the porous media and vaporized by the heat conducted through the combustor wall. Experiments were conducted to evaluate heat transfer and combustion performance at various equivalence ratios, heat release rates, and inlet air temperatures. Results show low CO emissions over a range of equivalence ratios. NOx emissions were high at high heat release rates, indicating inadequate prevaporization and premixing of fuel with air. Heat recirculation and heat loss characteristics are presented at various operating conditions.