GOALI: Experimental and Computational Study of Bluff-body Flame Stabilization with Nonhomogeneous Upstream Mixing

获奖摘要建议书编号：CTS- 0553504首席研究员：Cetegen，Baki M.机构：康涅狄格大学提案标题：GOALI：非均匀上游混合的钝体火焰稳定的实验和计算研究在许多实际的燃烧装置中，包括飞机加力燃烧室，火焰稳定发生在高速湍流破坏流中，通过放置在燃料喷射器下游的钝体。 在火焰稳定区域中，混合物成分的显著空间和时间变化是预期的。 已经有许多关于完全预混或非预混火焰的实验研究，这些火焰由海崖体或旋流锚定，并且单独研究了混合物成分梯度中的火焰传播。 然而，有没有全面的调查，火焰稳定性的区域组成梯度和再循环热产品，尽管它们的相关性，在飞机推进系统的火焰稳定。 该项目的智力优势包括对高速流动中的钝体稳定部分预混火焰进行详细的实验研究，以及对火焰动力学和稳定性进行补充计算。 这项工作的目标是提高再循环，部分预混流的火焰传播的基本理解，评估模型的准确性，并检查预测火焰稳定的降阶模型。 这项研究的结果直接适用于目前使用钝体稳定的飞机加力燃烧室，但也将广泛适用于氢基合成气燃料的新燃烧室设计，这可能需要增强钝体稳定性以实现燃料灵活操作。 详细的激光诊断技术将被应用于发展一个深入的了解当地的条件，导致火焰吹离在高速，和混合物的不均匀性的影响，火焰吹离的开始和火焰结构之前吹离。 实验将在一个平面的二维配置，和测量技术将包括速度成像，火焰结构成像通过激光诱导荧光，和上游的混合物组成的配置文件。 为了与数值模拟兼容，将强调对边界条件的全面记录和控制。 实验研究的几何形状的计算建模将由我们在联合技术研究中心（UTRC）的GOALI合作伙伴进行。 对于实验研究的相同情况，将完成钝体火焰稳定的非定常数值模拟。 我们的目标将是评估这些模拟捕捉火焰传播的能力，在分层流和开发扩展的数值方法部分预混火焰稳定。 更广泛的科学影响，这项研究将是一个更好的基本了解火焰传播的部分预混流与再循环。 这对工业设备的设计有直接的影响，如飞机发动机的加力燃烧室，但也扩大了对湍流中基本火焰行为的理解，这可能广泛适用于改进新燃料的燃烧室设计。 该项目将有助于培训两名研究生。 通过与UTRC直接合作，这些学生将获得这一领域的经验，他们将为美国在先进推进系统设计领域的竞争力做出贡献。该项目由燃烧和等离子体系统计划和学术与工业联络资助机会（GOALI）计划共同资助。

Award AbstractProposal Number: CTS- 0553504 Principal Investigator: Cetegen, Baki M.Institution: University of ConnecticutProposal Title: GOALI: Experimental and Computational Study of Bluff-Body Flame Stabilization with Nonhomogeneous Upstream MixingIn many practical combustion devices, including aircraft augmentors, flame holding occurs in a high speed turbulent vitiated flow via bluff-bodies placed just downstream of fuel injectors. Significant spatial and temporal variations in mixture composition are expected in the flame stabilization region. There have been numerous experimental studies on fully premixed or nonpremixed flames anchored either by bluff bodies or swirling flow, and separate studies of flame propagation in mixture composition gradients. However, there have been no comprehensive investigations of flame stability in regions with both composition gradients and recirculating hot products, despite their relevance to flame holding in aircraft propulsion systems. The intellectual merits of this project involve a detailed experimental investigation of bluff-body stabilized partially-premixed flames in high velocity flows and a complementary computational effort on flame dynamics and stability. The goal of this work is to improve fundamental understanding of flame propagation in recirculating, partial-premixed flows, to assess model accuracy and to examine reduced order models for predicting flame stabilization. The results of this study are directly applicable to aircraft augmentors, which currently use bluff-body stabilization, but will also be broadly applicable to new combustor designs for hydrogen based syngas fuels, which may require enhanced bluff-body stabilization for fuel flexible operation. Detailed laser diagnostic techniques will be applied to develop an in-depth understanding of local conditions leading to flame blow-off at high velocities, and effects of mixture non-uniformities on the onset of flame blow-off and on flame structure prior to blow-off. The experiments will be performed in a planar two dimensional configuration, and the measurement techniques will include velocity imaging, flame structure imaging through laser-induced fluorescence, and upstream profiling of mixture composition. Thorough documentation and control of boundary conditions will be emphasized for compatibility with numerical simulations. Computational modeling of the geometries studied experimentally will be carried out by our GOALI partner at the United Technologies Research Center (UTRC). Unsteady numerical simulations of bluff-body flame holding will be completed for the same cases studied experimentally. The goal will be to assess the capabilities of these simulations to capture flame propagation in stratified flows and to develop extensions of the numerical approach to partially-premixed flame stabilization. The broader scientific impact of this research will be a better fundamental understanding of flame propagation in partially-premixed flows with recirculation. This has direct impact on the design of industrial devices such as augmentors for aircraft engines, but also expands understanding of basic flame behavior in turbulent flows that could be broadly applicable to improved combustor design for new fuels. The project will facilitate training of two graduate students. By working directly with UTRC, these students will gain experience in this field and they will contribute to the U.S. competitiveness in the area of advanced propulsion system design.This project is co-funded by the Combustion and Plasma Systems Program and the Grant Opportunities for Academic Liaison with Industry (GOALI) Program.