2013 Volume 55 Issue 171 Pages 67-72
In order to ignite fuel spray directly by a laser beam, it is necessary to investigate the characteristics of laserinduced breakdown ignition and generation of plasma as ignition sources in fuel spray. This study conducted experiments of laser-induced breakdown ignition in an ethanol spray and laser-induced breakdown in water mists by using the third harmonic of the Q-switched Nd:YAG laser. Photographs of the flame and the plasma were taken and laser beam energy for laser-induced breakdown was measured. The results of laser-induced breakdown ignition experiments show that the laserinduced breakdown ignition in a fuel spray was possible even at low incident energies that the laser-induced breakdown did not occur in air. The results of laser-induced breakdown experiments show that plasma was generated at the focal point in air, on the other hand, plasma was generated at multi-points in water mist. And the laser-induced breakdown occurred at much lower incident energy than that in air. The probability of breakdown occurrence increased with the incident energy and showed higher value at higher number density of water droplet.
