Effect of premixing on nitric oxide formation.

Emissions from a simple 10-cm diameter tube combustor burning a premixed, gaseous propane/air mixture were measured. Inlet conditions included a temperature of 590 K, pressure of 5.5 atm, and reference velocity of 23 m/sec for a range of equivalence ratios from the lean limit to slightly richer than stoichiometric. A nitric oxide emission index of 1 g NO2/kg fuel was measured for an equivalence ratio of 0.57.