3D flame surface measurements in low-turbulence Bunsen flames via scanning and orthogonal cross-planar techniques
3D flame surface measurements in low-turbulence Bunsen flames via scanning and orthogonal cross-planar techniques
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DOI：
10.1016/j.combustflame.2023.113103
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发表时间：
2023-12
影响因子：
4.4
通讯作者：
Yutao Zheng;Lee Weller;Simone Hochgreb
中科院分区：
文献类型：
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作者：
Yutao Zheng;Lee Weller;Simone Hochgreb
采用基于声光偏转器（AOD）的激光扫描技术重建了湍流本生火焰中的准瞬时三维火焰表面。利用527 nm Nd: YLF高频激光，通过液滴Mie散射，从不同垂直平面上的一系列火焰轮廓重建了瞬时火焰表面积。根据燃料/空气混合物的总质量流率除以密度和非应变层流火焰速度m˙/(ρ u s L)，估计平均总火焰表面积< A>，并与估计的面积需求进行比较。火焰表面密度（FSD， 2D和3D）和火焰表面曲率也被测量，并与使用3D交叉平面方法在特定位置获得的结果进行了比较。在火焰刷的给定位置测量到的差异高达67%，3D FSD值通常高于相应的2D测量值。目前的测量是FSD和3D曲率的第一次比较，比较扫描和正交交叉平面技术允许在两个正交平面上测量2D火焰轮廓，从而提高了确定3D火焰表面主曲率的精度。利用高频扫描技术重建了湍流本生火焰表面。首次测量了三维火焰表面积值，并将其与燃烧所需的总入射质量流量面积进行了比较。通过扫描技术测量了局部三维FSD值，并首次将其与交叉平面技术的相应测量值进行了比较。结合扫描和交叉平面技术测量火焰表面的真实三维主曲率，以提供足够的精度。
Quasi-instantaneous 3D flame surfaces were reconstructed in a turbulent Bunsen flame via a laser scanning technique based on an acoustic-optic-deflector (AOD). Instantaneous flame surface areas were reconstructed from a series of flame contours at different vertical planes via droplet Mie scattering with a Nd: YLF high-frequency laser at 527 nm. Mean total flame surface areas< A> were estimated and compared with estimated area demands based on total mass flow rates of fuel/air mixture divided by density and unstrained laminar flame speed, m˙/(ρ u s L). Flame surface density (FSD, both 2D and 3D) and flame surface curvatures were also measured and compared with those acquired using 3D cross-planar methods at particular locations. Differences of up to 67% were measured at a given location in the flame brush, with 3D FSD values generally higher than corresponding 2D measurements. The present measurements are the first comparisons of FSD and 3D curvatures comparing scanning and orthogonal cross-planar techniques allowed the measurement of 2D flame contours on two orthogonal planes, leading to improved accuracy in the determination of principal curvatures in 3D flame surfaces. Novelty and significance statement Turbulent Bunsen flame surfaces were reconstructed by a high frequency scanning technique. Values of the 3D flame surface area were for the first time measured and compared to the required area for burning the total incoming mass flow rate. Values of local 3D FSD were measured via the scanning technique and for the first time compared to corresponding measurements using cross-planar technique. True 3D principal curvatures of flame surfaces were measured by combining scanning and cross-planar techniques to provide a sufficient accuracy.