Experimental Evaluation of Evaporation Enhancement with Porous Media in Liquid-Fueled Burners

Potential benefits of using a porous medium to enhance evaporation in liquid-fueled burners have been experimentally evaluated. An open-cell, silicon carbide-coated, carbon-carbon ceramic foam was used as a porous medium. Aviation-type kerosene was sprayed into a coflowing, preheated air environment using an air-blast atomizer, and the spray subsequently entered the porous medium. The minimum combustion heat feedback rate required for complete vaporization and the vapor concentration downstream of the porous medium were measured. Surface temperature measurements showed that the temperature of the porous medium was uniform within 10 K. The minimum heat feedback rate required for complete vaporization increased as the distance between the porous medium and the injector was decreased. Under the present conditions, with porous media and combustion heat feedback, complete vaporization was achieved at a coflow air temperature of 400 K. Without porous media, however, a minimum coflow air temperature of 500 K was required to achieve the same quality of evaporation. Measurements revealed that a combustion heat feedback rate of 1% produced average vapor concentrations of 63% and 43% more than that with no heat feedback at equivalence ratios of 0.3 and 0.6, respectively.