Combustion and Flame ( IF 4.4 ) Pub Date : 2021-09-05 , DOI: 10.1016/j.combustflame.2021.111707 Florian Zentgraf 1 , Pascal Johe 1 , Matthias Steinhausen 2 , Christian Hasse 2 , Max Greifenstein 1 , Andrew D. Cutler 3 , Robert S. Barlow 4 , Andreas Dreizler 1
This study focuses on exploring the thermochemistry in flame-wall interaction (FWI) for fully premixed side-wall quenching of a laminar, atmospheric-pressure dimethyl ether flame at equivalence ratio by simultaneous measurement of CO and CO mole fractions and gas phase temperature . The applied laser diagnostics are dual-pump coherent anti-Stokes Raman spectroscopy (DP-CARS) targeting N and CO, laser-induced fluorescence of CO and OH, as well as thermographic phosphor thermometry. The extension to DP-CARS to study FWI processes is the first of its kind, previous studies only provided (CO,) measurements. The laser diagnostics are benchmarked and calibrated to an adiabatic test case and assessed in accuracy and precision. Subsequently, the approach is used to measure the thermochemistry close to a quenching wall. The nominal flame-to-wall distances from the experiment well match the numerical simulation data with a marginal offset of 20 µm. Conditioning the thermochemical data with respect to the instantaneous quenching point, named quenching-point conditioning, enables a novel tracing of the wall-parallel chemistry evolution across the quenching location. The study provides the first comparison of experimental three-scalar measurements (CO,CO,) with two-dimensional (2D) fully-resolved chemistry and transport (FCT) simulations. The validation of numerical simulations can now rely on the three scalars (CO,CO,) instead of the two scalars (CO,) in past studies. The evaluation reveals that this novel three-scalar measurement allows highly sensitive probing of the thermochemical states and is clearly superior to the previously applied two-scalar approach. CO is less affected by the quenching wall compared to CO. Differential diffusion effects are experimentally confirmed by comparison to 2D-FCT, with the (CO) state space being more sensitive than (CO,). As the experimental methodology proved feasible for laminar operation, a transfer to turbulent cases, where the numerical analysis using direct numerical simulations (DNS) including FCT is limited, appears promising.
中文翻译:
通过使用激光诊断同时定量测量 CO 2 、CO 和温度,详细评估侧壁淬火燃烧器中的热化学
本研究的重点是探索火焰-壁面相互作用 (FWI) 中的热化学,以在当量比下对层流、常压二甲醚火焰进行完全预混的侧壁淬火 通过同时测量 CO 和 CO 摩尔分数和气相温度 . 应用的激光诊断是针对 N 的双泵相干反斯托克斯拉曼光谱 (DP-CARS) 和一氧化碳,CO 和 OH 的激光诱导荧光,以及热成像磷光体测温法。扩展到 DP-CARS 以研究 FWI 过程是同类中的第一个,以前的研究仅提供(CO,) 测量。激光诊断根据绝热测试案例进行基准测试和校准,并在准确性和精确度方面进行评估。随后,该方法用于测量靠近淬火壁的热化学。实验中标称火焰到壁的距离与数值模拟数据相匹配,边缘偏移为 20 µm。调节相对于瞬时淬火点的热化学数据,称为淬火点调节,能够对淬火位置的壁平行化学演化进行新的追踪。该研究首次比较了实验性三标量测量 (CO,CO,) 具有二维 (2D) 完全解析的化学和传输 (FCT) 模拟。数值模拟的验证现在可以依赖于三个标量 (CO,CO,) 而不是两个标量 (CO,) 在过去的研究中。评估表明,这种新颖的三标量测量允许对热化学状态进行高度灵敏的探测,并且明显优于以前应用的二标量方法。二氧化碳 与 CO 相比,受淬火壁的影响较小。通过与 2D-FCT 相比,实验证实了微分扩散效应,其中(CO) 状态空间比 (CO,)。由于实验方法证明对于层流操作是可行的,转移到湍流情况下,使用直接数值模拟 (DNS) 包括 FCT 的数值分析是有限的,似乎很有希望。