The goal of the current work is to understand the effects of premixing on soot processes in an iso-octane, axisymmetric, co-flow, laminar flame at atmospheric pressure. The flames investigated are non-premixed and partially-premixed (jet equivalence ratios of 24, 15, 12, 9 and 6). The total carbon flow rate is kept constant to facilitate comparison among the six flames. Laser-induced incandescence and laser extinction are applied to obtain two-dimensional soot volume fraction. The experimental results show that the spatial distribution of soot changes with premixing; the peak soot volume fraction location is in the annular region in the non-premixed flame and transitions to the centerline as the jet equivalence ratio is reduced. Numerical simulations are performed using a detailed iso-octane fuel chemistry and bi-variate soot model. The numerical model captures the changes in the spatial distribution of soot due to premixing, as in the experiment. Similar to the change in the soot distribution, the soot production processes, including nucleation, surface growth, and PAH condensation, show the transition behavior with premixing. The simulation shows that the location of peak PAH dimer concentration shifts from the annular region towards the centerline with premixing. As a result, the location where soot nucleation and PAH condensation rates peak show similar transition as observed in the PAH dimer concentration. Furthermore, PAH dimer concentration decreases due to premixing, leading to a decrease in the soot nucleation and soot growth due to PAH condensation. Additionally, soot growth due to surface reactions decrease with premixing due to the reduction in number of active sites on the soot surface.

当前工作的目的是了解大气压下异辛烷，轴对称，并流，层流火焰中预混合对烟灰过程的影响。研究的火焰是未预混合和部分预混合的（射流当量比为24、15、12、9和6）。总碳流量保持恒定，以便于在六个火焰之间进行比较。应用激光诱导的白炽和激光消光以获得二维烟灰体积分数。实验结果表明，烟灰的空间分布随预混合而变化；烟灰体积分数的峰值位置位于非预混火焰中的环形区域，并随着射流当量比的减小而过渡到中心线。使用详细的iso执行数值模拟-辛烷燃料化学和二元碳烟模型。与实验中一样，该数值模型捕获了由于预混合而导致的烟尘空间分布的变化。类似于烟尘分布的变化，烟尘生产过程（包括成核，表面生长和PAH冷凝）显示出预混合的过渡行为。模拟表明，在预混合的情况下，峰值PAH二聚体浓度的位置从环形区域向中心线移动。结果，烟灰成核和PAH凝结速率达到峰值的位置显示出与在PAH二聚体浓度中观察到的相近的转变。此外，由于预混合，PAH二聚体浓度降低，导致由于PAH冷凝而导致的烟灰成核和烟灰生长减少。此外，