A single pulse from a TEA CO2 laser is used to heat 1:7:14 mixtures of SF6:CH4:O2 to temperatures near 1000 K. A short- or long-duration pulse (one-half the energy deposited in 0.25 or 0.82 μsec, respectively) from a second TEA CO2 laser is used to ignite the mixture. At comparable values of absorbed energy from the second laser, ignition-delay times for the long-duration secondary pulse are approximately twice those for the short-duration pulse. Ignition of the hot mixture requires about 10% less absorbed energy with the short-duration pulse than with the long-duration pulse. These results indicate the short-duration pulse is more effective in producing a high population density of reactive species that initiate the reactions necessary for ignition.
© 1981 Optical Society of America
Original Manuscript: January 12, 1981
Published: July 1, 1981
Ronald A. Hill, "Ignition-delay times in laser initiated combustion," Appl. Opt. 20, 2239-2242 (1981)