Numerical Study Of The Swirl Burner

The recirculation zone in the swirl burner due to the strong fluid rotary motionhas a significant role for stablizing flame, improving combustion efficiency andreducing pollutants, so that swirl burner attracts more and more focus, but the researchin sudden expansion structure is rare.In this paper, the cold laminar flow in the sudden expansion, the cold andcombustion flow in swirl burner are simulated. The influence mechanism of differentsudden expansion steps and the impact of different working conditions on flow areanalyzed.Reynolds number from10to90, the number of sudden expansion steps from1to5. The total pressure loss is reduced as the Reynolds number and the number of stepsincrease. In the case of constant combustion chamber length, the flow of the suddenexpansion with multisteps burner is more fully development. The performance of thesudden expansion with multisteps burner is better than that of the sudden expansionwith one step.As the swirl number increases, the center circumfluence area and total pressureloss increase. As axial velocity ratio increases, the center circumfluence area and totalpressure loss decrease. As the number of steps increases, the center circumfluencearea and the total pressure loss decrease, the distribution of methane concentrationbecomes more uniform. The performance of the sudden expansion with five stepsburner is best.From the results of the reaction flow in the swirl burner, with the increases ofaxial velocity ratio, the combustion efficiency and the overall temperature decrease,the distribution of the radial temperature at the exit becomes nonuniform. Larger inlettemperature can make more uniform distribution of the radical temperature at the exit,higher combustion efficiency and overall temperature. With the increases of swirlnumber, combustion efficiency and total temperature increase, the radial temperaturedistribution becomes uniform at the exit. Therefore, appropriate swirl number shouldbe choosed in the engineering, the swirler life would decreases with larger swirlnumber, and the advantage of the swirl combustion cannot be played out if swirl number is low.