An absolute irradiance-calibrated Laser Induced Incandescence (LII) technique and a standard particle image velocimetry (PIV) technique were utilized to collect quantitative data on soot volume fraction and corresponding flow strain rates of diluted ethylene-air non-premixed counterflow flames. Pressures up to 30 atm were explored with increasing dilution with nitrogen or helium to minimize flow strain limits at which incipient soot was detected and to maintain the flame in laminar mode. For weakly strained flames considered, the species and velocity boundary conditions were used to predict the gas-phase flame structure (e.g., temperature and major species). The predicted gas properties, together with soot particle temperature decay rate measured by two-color pyrometry were used in the LII heat transfer model to extract the effective soot particle size and particle number density. Estimates of global activation energy of incipient soot yield with pressure indicated a sudden change around a pressure of 20 atm, which may be attributed to a shift in soot nucleation and growth pathways.

利用绝对辐照度校准的激光诱导白炽灯（LII）技术和标准粒子图像测速仪（PIV）技术收集有关烟尘体积分数和稀释的乙烯-空气非预混逆流火焰的相应流变速率的定量数据。在增加氮气或氦气稀释度的情况下，探索了高达30个大气压的压力，以最大程度地减小检测到初生烟灰的流动应变极限，并将火焰保持在层流模式。对于考虑的弱应变火焰，使用种类和速度边界条件来预测气相火焰的结构（例如温度和主要种类）。预测的气体特性 在LII传热模型中，结合通过双色高温法测量的烟尘颗粒温度衰减率，来提取有效的烟尘颗粒大小和颗粒数密度。初生烟灰产量随压力的总体活化能估计表明，在20个大气压的压力附近发生突然变化，这可能归因于烟灰成核和生长途径的转变。