Inhibition of hydrogen-oxygen-nitrogen diffusion flames by potassium superoxide

Abstract

The afterburning of hydrogen and carbon monoxide in rocket plume gases Is Inhibited by the addition of potassium salts to the rocket propellant formulation. The mechanism of the inhibition is not completely understood, but it is believed to Involve chain breaking of H and OH' reactions by K0, KOH, and KO2. The present study is directed toward clarifying the reactions involved. Inhibition effects are reported of K0 and Ko2 vapor on the combustion of preheated nitrogen-diluted hydrogen-oxygen opposed-jet diffusion flames for various lean to rich mixtures with overall stoichiometric ratios(+) ranging from 0 .72 to 1.21. These effects are Interpreted from the spectral emission measured from Incremental scans of a flat flame in the 3800 - 3000 cm' range for water and OH bands. It is concluded that K0 vapors Inhibit the combustion of hydrogen over the range studied of 0 .1 to 1692 molar ppm for lean to rich flames with t's of 0.98 to 1.21. KO2 inhibits at concentrations equivalent to its equilibrium vapor pressure at 160° to 320°C for ifs of 0 .72 to 1.21.