PROMPT NO SCALING IN-DIFFUSION FLAMES - EFFECTS OF STRAIN AND PRESSURE

Nitric oxide emission control is one of the major problems encountered in the development of combustion chambers for all types of applicatio ns. Scaling rules describing the dependence of NO, emission on operati ng parameters such as pressure, mixture ratio or turbulence intensity provide useful design guidelines. While such rules are well establishe d for thermal NO, much less is available for prompt NO. This specific problem is considered in this article. The influence of pressure and s train rate on prompt NO production is investigated experimentally in a laminar counterflow diffusion flame. The results relative to the pres sure dependence compare well with complex chemistry calculations in we ll-stirred reactors. The strain rate dependence is in good agreement w ith previous theoretical results found in the literature. The scaling established for the laminar flame is then applied to a turbulent nonpr emixed combustor in order to describe the influence of strain on promp t NO production. The results are analyzed on the basis of a decomposit ion between global chemical effects and local effects due to strain. T he final expression given for the prompt NO scaling in the turbulent d iffusion flame provides a good correlation of experimental measurement s.