Experimental study on combustion in porous media with a reciprocating flow system

The results of an experimental study on the behavior of a reciprocating superadiabatic combustion system, the attainable flammable limits, and the low NOx and CO emissions which can be achieved with this system, are reported. Attention was focused on the influence of the dominating parameters, i.e., how velocity, half cycle, and equivalence ratio, on the formation of temperature profiles in the porous body. Hereby the flammable limit was extended to the extremely low equivalence ratio of 0.026. In addition, the influence of the parameters on the levels of NOx and CO emissions was experimentally clarified and the emission levels are discussed with regard to the obtained temperature profiles. Extremely low NOx emissions of less than one ppm were obtained for all conditions investigated. The CO emissions were strongly dependent on the how velocity and the type of porous medium used. For favorable conditions, low CO emissions in the order of ppm were also obtained. (C) 1997 by The Combustion Institute.