No abstract

The possibility of intensification of ignition of a methane-oxygen mixture in a supersonic flow behind the front of an oblique shock wave by means of excitation of O 2 molecules to the states a 1 Δ g and b 1 Σ + g in an electric discharge is discussed. Through numerical simulations, activation of O 2 molecules by an electric discharge is demonstrated to speed up chain reactions in the CH 4 -O 2 mixture and to reduce the induction-zone length. Even a small amount of energy input to O 2 molecules in the discharge (≈3 ·0 −2 J/cm 3 ) can reduce the ignition-delay length by a factor of hundreds and initiate combustion at distances of ≈1 m from the discharge zone at comparatively low temperatures of the gas behind the front (≈1000 K) and moderate pressures (≈10 5 Pa). Excitation of O 2 molecules by an electric discharge is much more efficient than simple heating of the mixture.

The combustion kinetics of H 2 -air mixtures containing small amounts (<1%) of ozone is analyzed for the case of excitation of asymmetric vibrations of O 3 molecules by CO 2 laser radiation with a wavelength of ≈9.7 µm. It is shown that the irradiation leads to acceleration of the collisional dissociation of O 3 molecules, activation of the chain ignition mechanism, and a decrease in the induction period and ignition temperature. The excitation of asymmetric vibrations of O 3 molecules by the CO 2 laser radiation is 10-10 3 times more effective than the currently used method of combustion initiation based on local heating of a medium by IR radiation.

No abstract

No abstract