DENSITY INDUCTION TIMES BEHIND SHOCK WAVES IN VERY LEAN MIXTURES OF D2, H2, C2H2 AND C2H4 WITH O2.
GENERAL ELECTRIC RESEARCH LAB SCHENECTADY N Y
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The induction time for shock wave-induced exothermic reaction in lean O2-D2, O2-H2, O2-C2H2, and O2-C2H4 mixtures was measured in the constant area shock tube using optical interferometry. For fueloxygen ratios of a few per cent and for 1100 T2200K, the gas time from the shock to the first decrease in density is given in molesliter, seconds, and degrees K. All fuels show essentially the same activation energy approx. 17.3 kcal mole and with respect to H2, the induction times for D2, C2H2, and C2H4 are about 1.5, 0.5, and 0.4, respectively. The more nearly stoichiometric mixtures show induction times inversely proportional to the geometric mean reactant concentration, and the dependence on the fuel concentration increases with decreasing fuelO2 ratio, the dependence on O2 vanishing for the leanest O2-C2H4 mixtures. The vibrationally relaxed but unreacted density is always attained prior to exothermic reaction, and changing the relation time with respect to the induction time has no effect on the latter within the data scatter. Author
- Physical Chemistry
- Fluid Mechanics
- Combustion and Ignition