الفهرس 
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Abstract
The combustion characteristics of Natural gases inside porous media burners in lean mixture have been tested and investigated experimentally and numerically under steady state conditions. The wall of burner chamber has been in atmospheric air without insulation around it. Two types of porous media have been used such as ceramic packed bed (Alumina Al2O3) and (Zirconia ZrO2) with different balls diameters 3mm, 4mm, 5mm and 6mm to change the porosity of bed. The flame stability region in porous media with lean mixture is the main factors of this thesis. The temperature, flue gases emissions such as CO, NOx and CO2 in products gases are monitored during experiment. The influence of working fluid velocity and porous media type on the flame stability and burning temperature and the flue gases emissions have been presented and investigated. The results indicate that: The ball diameter (porosity) of porous media has significant effect on the position of the reaction zone with respect to axis of the burner, as the ball diameter of porous
media increase the reaction zone moves toward the bottom of the burner. The air fuel ratio has a great effect on temperature distribution within the bed for the same inlet velocity but it has no effect on the reaction zone position. The inlet air velocity has an effect on the reaction zone position and the temperature distribution in the porous media, as the inlet air velocity increase the reaction zone position moves to the top of the burner and the temperature inside the porous media increase. With respect to the porous media material the reaction zone volume increase with Zirconia material and the consequently on the temperature distribution. The
measurements of NOx and CO as an exhaust emissions reveals the measured values
with respect to the combustion in porous media is notably lower than the ordinary
burner.