A STUDY OF SHOCK WAVE INDUCED REACTIONS.
Final scientific rept., 15 Jan 62-24 Jun 66,
GENERAL ELECTRIC CO SCHENECTADY N Y RESEARCH AND DEVELOPMENT CENTER
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A technique for generation of a laminar reaction zone in a detonable mix was found. Density measurements in these and in incident shock experiments confirmed existence of the von Neumann spike and demonstrated that the density there corresponds to full vibrational relaxation without chemical reaction for the combustion of D2, H2, C2H2, C2H4, CH4, and CO. A systematic study of vibrational relaxation of diatoms has resulted in an empirical correlation of relaxation time as a function of oscillator strength, reduced mass, and temperature that has superior predictive abilities. It was demonstrated that induction time is an insensitive function of the relaxation time of the reactants. The activation energy for shock-induced exothermic reaction in D2, H2, C2H2, and C2H4 is measured to be about 17.3 kcalmole, and the induction times are in the ratio of 1.5, 1, 0.5, and 0.4, respectively, for a very lean stoichiometry. In reflected shock ignition studies, an activation energy of 17.3 kcalmole is approached for low-pressure experiments and at higher pressure the density-normalized induction time increases markedly with pressure, yielding a much higher apparent activation energy. This is presumably due to the increasing importance at higher pressures of the termolecular recombination reaction forming HO2. The observed result is that the actual induction time rather than being inversely proportional to pressure, as it is above 1100K, varies directly with pressure and can be much less at 1 atm than at 5 atm. Author
- Physical Chemistry
- Fluid Mechanics
- Combustion and Ignition