This study reports novel measurements on the effects of pressure on the lift-off behavior and the stabilization mechanism of turbulent non-premixed methane jet flames. A high-pressure combustion duct (HPCD) was operated within the range of pressure P = 1–7 bar using jet velocities of 4 m.s⁻¹ ≤U_j≤30 m.s⁻¹ and co-flow velocities of 0.23 m.s⁻¹ ≤U_c≤0.60 m.s⁻¹. Lift-off heights were measured from chemiluminescence pictures while joint images of hydroxyl and velocity, performed using joint PLIF-OH/PIV, were used to extract information about the stabilization mechanism. It is shown that while the lift-off height generally increases with pressure, the impact of pressure depends on the magnitude of the co-flow velocity. For U_c = 0.30 m.s⁻¹, the flame's base remains near the nozzle over the entire pressure range and the measured flame speeds indicate that edge-flame stabilization is dominant. The slope of the lift-off height vs. jet velocity curves is positive. For U_c = 0.60 m.s⁻¹ and P > 2 bar, the flame stabilizes further downstream and a transition to turbulent premixed flame propagation appears to have occurred. At these conditions, the slope of the lift-off height vs. jet velocity curves becomes negative. This reversal at high pressure is a new result for methane. More importantly, the transition in the stabilization mechanism with increasing U_c is consistent with results reported earlier for ethylene and appears to be independent of the fuel.

这项研究报告了关于压力对湍流非预混合甲烷射流火焰升起行为和稳定机制的影响的新颖测量方法。高压燃烧导管（HPCD）中压力的范围内操作P 使用的4毫秒射流速度= 1-7巴^{- 1} ≤ ü _Ĵ ≤30毫秒^-1的0.23毫秒和共流速^{- 1} ≤ ü _ç ≤0.60毫秒^-1。从化学发光图片测量剥离高度，同时使用联合PLIF-OH / PIV进行的羟基和速度联合图像用于提取有关稳定机理的信息。结果表明，虽然升程高度通常随压力而增加，但压力的影响取决于同流速度的大小。当U _c  = 0.30 ms ^-1时，火焰的基础在整个压力范围内都保持在喷嘴附近，并且测得的火焰速度表明边缘火焰稳定是主要因素。提离高度与喷射速度曲线的斜率是正的。对于U _c  = 0.60 ms ^-1和P > 2 bar，火焰进一步向下游稳定，并且似乎发生了向湍流预混火焰传播的过渡。在这些条件下，提离高度与射流速度曲线的斜率变为负值。高压下的这种逆转是甲烷的新结果。更重要的是，随着U _c的增加，稳定机理的转变与先前报道的乙烯结果一致，并且似乎与燃料无关。