多孔介质表面预混火焰熄火特性实验

对微型燃烧室中多孔介质表面预混火焰开展了不同孔径、孔隙率的多孔介质出口流场特性和熄火特性实验研究.研究结果表明:相对于圆管流,多孔介质出口流场边界层变薄,主流区宽度增加约50%,速度波动最大可达到前者的2.2倍.多孔介质孔径相同时,随孔隙率减小,或孔隙率相同时,随孔径减小,主流区的速度波动幅值均减小,在小孔径下更为明显,最大速度波动幅值从2.435m/s减小至1.099m/s.多孔介质表面预混火焰的熄火特性受出口流场和火焰形态的影响很大,孔隙率减小或孔径减小都会使相同当量比下熄火速度增加,多孔介质参数的影响最大可使熄火速度增加近1倍. 

Experiment of blow-out performance of premixed flame on porous media surface

Experimental investigation was conducted on the premixed flame on porous media surface used for micro combustor, and the flow field characteristics and blow-out performance of porous media under different pore sizes and porosities were obtained. The research results indicate that the boundary layers of the flow field at the exit of porous media become thinner compared with pipe flow; the width of mainstream region is increased by about 50%, and the maximum speed fluctuation amplitude in this region reaches 2.2 times of the former. When the porosity of porous media decreases with the constant pore size, or the pore size of porous media decreases with the constant porosity, the speed fluctuation amplitude of mainstream region decreases. This becomes more obvious under small pore size condition with the maximum speed fluctuation amplitude decreasing from 2.435m/s to 1.099m/s. The flow field at the exit and flame shape have great influence on the blow-out performance of premixed flame on porous media surface. With the decrease of pore size and porosity, the blow-out velocity increases under the same equivalence ratio. The influences of porous media parameters can nearly double the blow-out velocity.