| This thesis reports on a method to evaluate the chemical delay time in hypergolic bi-propellant systems. A laser diagnostic technique is described which employs a drop test method. The results of ignition delay time and chemical delay time measurements are reported with red fuming nitric acid and white fuming nitric acid as oxidizer in combination with various fuel and fuel mixtures including hydrazine, unsymmetrical dimethylhydrazine, monomethylhydrazine, furfuryl alcohol, aniline, hydrazine-unsymmetrical dimethylhydrazine, furfuryl alcohol-aniline, furfuryl alcohol-unsymmetrical dimethylhydrazine, and monomethylhydrazine-hydrazine. Previous investigations of these fuel combinations are discussed. The high temporal and spatial resolution of the technique used in this study provides information on both mixing and chemical delay time embedded within the ignition delay. Analysis of the region of chemical delay as a function of fuel mixture composition is discussed. The quantitative results show that for red fuming nitric acid reacted with hydrazine the oxidizer concentration plays a negligible role in the reaction mechanism. This result indicates that chemical delay time measurements can also provide information on the reaction pathways for hypergolic combustion. For 10-40% furfuryl alcohol mixed with unsymmetrical dimethylhydrazine, the system provides chemical delays comparable to pure unsymmetrical dimethylhydrazine reacted with red fuming nitric acid and is less toxic. This result is unique because it shows evidence that mixtures can be used to decrease the toxicity of the fuel without compromising the reactivity. |
