Combustion performance of a two-layer porous inert medium burner at different low powers

Abstract- Improving the performance of modern combustion systems in many engineering application fields has great favorable impact on the energy conservation and global environmental pollution. This can be done through developing state of the art techniques for this purpose. One of them is the combustion within porous media burners. The two-layer porous inert medium burner (PIM) has significant merits such as high burning ratios, very low emission levels, high levels of the combustion stability, and operation at ultra-lean excess air ratios. The main work is to examine a new PIM design has a square cross-section area with two porous layers namely, aluminum oxide as the subcritical layer (quenching layer) and silicon carbide (SiC) as the supercritical layer each of 130 x 130 mm. The burner performance was estimated by recording the axial temperature profile at the selected operated thermal powers. The extent of the combustion stability limits between the flashback limit to the blow-off limit was improved. The excess air ratios of the stability limits at powers 0.7, 1.5, 2.5 kW were deduced to be (1.9-2.8), (1.8-2.6), and (1.5-2.4), respectively. The exhaust emissions were measured by a gas analyzer. The results revealed low levels of the CO emissions and decreased with increasing the operated thermal power. The CO ppm recorded the order of hundreds at powers 0.7 and 1.5 kW but reached the order of tens at power 2.5 kW. The NOx emission recorded ultra-low levels and increase with increasing the thermal power but not exceed 2 ppm