In the current study, the auto-ignition dynamics of cold fuel jets issuing into a high-temperature, vitiated environments is investigated. Due to the short time scale of these events, high-speed measurements are used to resolve the coupled spatio-temporal behavior. The present study uses high-speed (20-kHz) OH* chemiluminescence imaging to identify the location and timing of the formation of the initial ignition kernels, providing visualization of the ignition dynamics and a detailed statistical evaluation of ignition heights and ignition delay times across a broad parameter space which includes variations in fuel type, dilution levels, coflow temperature, and coflow oxidizer content. The auto-ignition location and ignition delay times show a strong sensitivity to coflow temperature with increased sensitivities at lower coflow temperatures. Comparisons between kernel formation location for the transient jet and the fluctuating flame base of the subsequent, steady-state flame is presented, highlighting the role of flame propagation on flame stabilization. Results indicate that at lower temperatures the flame stabilization mechanism is dominated by auto-ignition, but at higher coflow temperatures, flame propagation plays a key role. The effects of variations in the hot, coflow oxidizer content on ignition properties were found to be noticeable, but still significantly less than variations in the temperature.

在当前的研究中，研究了向高温，通风环境中排放的冷燃料射流的自燃动力学。由于这些事件的时间尺度较短，因此使用高速测量来解决耦合的时空行为。本研究使用高速（20 kHz）OH *化学发光成像来确定初始点火核形成的位置和时间，提供点火动力学的可视化以及整个点火高度和点火延迟时间的详细统计评估广阔的参数空间，其中包括燃料类型，稀释水平，同流温度和同流氧化剂含量的变化。自燃位置和点火延迟时间显示出对同流温度的强烈敏感性，并在较低的同流温度下增加了敏感性。比较了瞬态射流的核形成位置和随后的稳态火焰的波动火焰基部，从而突出了火焰传播对火焰稳定的作用。结果表明，在较低温度下，火焰稳定机制主要由自燃控制，而在较高共流温度下，火焰传播起着关键作用。已经发现，高温共流氧化剂含量的变化对着火性能的影响是明显的，但仍远小于温度的变化。结果表明，在较低温度下，火焰稳定机制主要由自燃控制，而在较高共流温度下，火焰传播起着关键作用。已经发现，高温共流氧化剂含量的变化对着火性能的影响是明显的，但仍远小于温度的变化。结果表明，在较低温度下，火焰稳定机制主要由自燃控制，而在较高共流温度下，火焰传播起着关键作用。已经发现，高温共流氧化剂含量的变化对着火性能的影响是明显的，但仍远小于温度的变化。