Experimental Study On Flame Stability Characteristics Of Porous Medium Bluff-body

In aviation turbine engines, rocket ramjet, rotary kiln and other combustion chambers, the high-speed air flow frequently cause flame instability. V-solid bluff body was used to form a stable recirculation zone to stabilize the flame in the actual application. However, a lot of research and application show that, in combustion chamber, this kind of flame stabilizer can lead to large flow loss and narrow the flame stability boundary, decrease the combustion efficiency, prone to generate oscillating combustion. In this paper, the porous media was investigated to make flame holder instead of solid bluff body. The special space structure, large specific heat and specific surface area of porous media can reduce the flow loss effectively, stabilize the flame.Based on the comparative trials of porous media and solid bluff body, the possibility of using porous media bluff-body to stabilize flame was reseached. The main research works of this paper are focused on following areas:(1) In low-speed flows, a DPIV(Digital Particale Image Velocimetry)system was used to measure the velocity distribution. At the same flow condition, the differences of wake flow of porous medium and solid bluff body can be observed by average velocity field, stream function graph and vorticity field.(2) The size and position of recirculation zone depend on the capability of preheating fresh fule and air mixing by high-temperature fuel in the downstream of bluff body.