Experimental Study Of Flame Characteristics For Ethanol-air Mixture Ignited By Laser

With the development of the new production technology of ethanol, Bio-ethanol has become one of the most widely used biomass fuels in the world. In the meantime, laser ignition technology as the vehicle engine ignition system is increasingly widespread because of its higher ignition energy and adjustable ignition position. Moreover, laser ignition can easily achieve multi-point ignition. In order to take full advantage of laser ignition and bio-ethanol, for the initial pressure and temperature were 0.1 MPa and 358 K respectively, we researched the flame characteristics of ethanol-air ignited by laser, such as the laminar burning velocity. Simultaneously, combustion characteristics under different ignition system were compared.1. Ethanol-air mixtures ignited by laser were researched by using constant volume combustion chamber. High speed schlieren imaging system was used to record flame development process at different equivalence ratios 0.6-1.6 and the pressure curve in the chamber was recorded by using the charge amplifier and digital oscilloscope. In the extraction process of flame radius, the Photoshop pixel conversion method was proposed and compared with the traditional double sides approximate process to verify the correctnesss of Photoshop pixel conversion method. The linear extrapolation and nonlinear extrapolation method were used to calculate the unstretched laminar propagation velocity. Then, other combustion characteristics, such as mass combustion flux, Markstein length, peak pressure, fuel mass fraction, heat release rate and so on, were analyzed.2. A comprehensive summary of the laser ignition process was summarized, especially the formation process of the plasma. In addition, flame combustion characteristics including laminar burning velocity, pressure and fuel mass fraction by laser ignition and central electrode ignition were compared. We found that under lean burn conditions, laminar burning velocity by laser ignition is higher than that of the central electrode ignition.