Non-premixed impinging jet flames with different coflow conditions are performed using PIV technology combined with numerical simulation to investigate flame instability in the vicinity of wall. Results indicate that the increase of coflow velocity results in a more chaotic flow field and higher fuel efficiency, and the increase of coflow temperature leads to ignition advance and the increase of NO concentration. These can be attributed to the coupling effect of Kelvin-Helmholtz instability, convective instability and Rayleigh-Taylor instability. High coflow velocity is more likely to induce Kelvin-Helmholtz instability and convective instability, and the increase of coflow temperature enhances Rayleigh-Taylor instability and convective instability. Due to the impact effect in the vicinity of wall, the flame instability is more likely to be induced at high coflow velocity. Meanwhile, the increase of coflow temperature can inhibit flame wrinkles. The flame dynamics is affected by turbulent mixing, head-on collision, shear and convective behaviors in non-premixed flames.

使用 PIV 技术结合数值模拟进行了具有不同协流条件的非预混撞击射流火焰，以研究壁面附近的火焰不稳定性。结果表明，协流速度的增加导致流场更加混乱和燃料效率更高，协流温度的增加导致点火提前和NO浓度增加。这些可归因于开尔文-亥姆霍兹不稳定性、对流不稳定性和瑞利-泰勒不稳定性的耦合效应。高顺流速度更容易诱发开尔文-亥姆霍兹不稳定性和对流不稳定性，顺流温度的升高增强了瑞利-泰勒不稳定性和对流不稳定性。由于壁面附近的冲击效应，火焰不稳定更有可能在高协流速度下引起。同时，提高coflow温度可以抑制火焰皱纹。火焰动力学受非预混火焰中的湍流混合、正面碰撞、剪切和对流行为的影响。