Atomic emission characteristics of a premixed acetylene-nitrous oxide, total consumption flame.
It is well known that most of the burners presently used to produce high temperature, premixed flames have the tendency to be discouragingly wasteful of the sample solution, often bringing only a small fraction of the amount used into the flame. This paper reports on the construction and performance of a highly efficient total consumption burner that produces a nonturbulent acetylene-nitrous oxide flame from premixed gases. The eighteen flame emission detection limits tabulated for a select group of elements compare favorably with the best values heretofore reported in the literature, and the apparent freedom of alkaline earth emission from phosphate interference indicates the total consumption flame here described to be less subject to chemical interference than is the conventional diffusion flame. The relatively low cost burner that has been developed is convenient to operate and can be quickly assembled from commercially available components.
Analytical Applications of the Flame Spectra of the Rare Earth Elements and Scandium.
The analytical potentialities of the simple spectra emitted by the rare earth elements when ethanol solutions of their perchlorates are aspirated into fuel-rich, oxyacetylene flames are evaluated. The sensitivities of detection of the strongest lines are tabulated and data showing the application of these spectra to the analysis of complex rare earth mixtures are presented. The relative standard deviations for these analyses ranged from plus or minus 1.3 to 3.7% of the amount present. (auth)
HYPERGOLIC REACTION MECHANISMS OF CATALYTICALLY PROMOTED FUELS WITH ROCKET GRADE HYDROGEN PEROXIDE
Abstract The coupling of the physical and chemical processes controlling the ignition delays (τ ign ) of hypergolic propellants complicates the direct analysis of the transient ignition processes. The transport properties of both the propellants and the ambient gas, and the heat of vaporization and reaction affect τ ign and must be considered experimentally. Furthermore, since hypergolic ignition occurs, by definition, on contact, the mechanics of initial contact and subsequent mixing can affect τ ign and must also be considered. Experimental results from a study of the hypergolic ignition of a catalytically promoted fuel with rocket grade hydrogen peroxide (RGHP) are presented. Statistical analysis of the experimental data was conducted to evaluate the relative effects of RGHP concentration, initial ambient pressure, and the ambient gas on τ ign . At RGHP concentrations of less than 92% in water, stable ignition was difficult to achieve. At sufficiently high Lewis number, an oscillatory ignition process is observed. A phenomenological model comprising mixing, RGHP decomposition, fuel heating and vaporization, and auto-ignition is presented and compared to the experimental results.