Influence Of Porous Medium On Stability Of Premixed Combustion In Body-force Field

In recent years, the development of space science and technology has changed rapidly, and burning issues in large body-force field were paid more and more attention. Flameout problem of aerospace engine in air often appears in previous researches, and such problem does not exist in the simulation experiment on the ground. A series researches by scholars show that the large body-force is the main reason causing the stability of combustion in engine to decrease, even leading to extinction. As a new material, porous media is widely used in the combustion field,because it can reduce pollutant emissions, improve combustion efficiency and combustion stability effectively. Then adding porous medium into combustor whether can effectively improve combustion instability problem? To solve this problem, the author studied the effect of porous medium on stability of flame in large body-force.First of all, establish two-dimensional axisymmetric model, one-way body-force is evenly distributed in the interior of the combustion chamber, and keep the body-force unchanged. By observing the flow field, temperature field, blow-off limit, backfire limit in the chamber and the variation of combustible flow rate limit, combustion reaction rate,shape of flame surface with the variation of body-force after adding porous medium in the chamber, analyze the effect of porous medium on characteristics of premixed flame. The result showed that porous medium can improve combustion reaction rate, decrease the change range of combustion reaction rate with body-force, and improve the stability of the premixed flame. The influence of porous medium on stability of flame is different when the magnitude and direction of one-way body-force are different.Establish 3D geometry model, and change the direction and magnitude of body-force by changing the jet angle. By observing the temperature distribution in combustor and flameout limit under different jet angles after adding porous medium in combustor, study the influence of porous medium on flame stability under different jet angles. The result showed that it is most favorable for stability of the flame as the jet angle is 0. Porous medium can improve the stability of flame,but the influence degrees under different jet angles are different.