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为了对低旋流流动特性及其对火焰传播与稳定影响进行深入理解,通过实验与数值模拟相结合的方法,对有限空间内低旋流流动与燃烧特性进行研究.结果表明:改变中心孔板小孔直径,可以形成不同旋流数的旋流喷射器;在冷态条件下,随着旋流数增加,在展向平面上逐渐形成“W”形速度矢量分布;在铅垂截面内,速度矢量分布存在一个环形高速区域、中心低速区和外侧低速区.由于燃烧气体吸热膨胀、涡量诱导和温度斜压效果,使得冷态高旋回流流动转变为了燃烧条件下低旋无回流流动;在有限空间内,低旋流燃烧没有形成脱体火焰,而是形成类似于扩散燃烧火焰;随着旋流数增大,温度分布边界和化学反应边界在展向平面逐渐缩短,而在铅垂截面逐渐扩大.
In order to deeply understand the characteristics of low-swirling flow and its influence on flame propagation and stability, the low-swirling flow and combustion characteristics in a limited space were studied through a combination of experiments and numerical simulations.The results showed that: In the cold condition, as the number of swirl increases, the “W” -shaped velocity vector distribution gradually forms on the spreading plane; in the vertical section There is a ring-shaped high-speed zone, a central low-speed zone and an outboard low-speed zone in the velocity vector distribution. Due to the endothermic expansion of combustion gas, vorticity induction and temperature-baroclinic effect, the cold- In the limited space, the low-swirl combustion did not form the off-body flame, but formed a flame similar to the diffusion combustion. As the swirl number increased, the temperature distribution boundary and the chemical reaction boundary gradually shortened in the spreading plane, Vertical cross-section gradually expanded.