Experimental and numerical investigation of non-premixed ammonia flames stabilized on a heated slot burner

IF 5.2 2区工程技术 Q2 ENERGY & FUELS

Proceedings of the Combustion Institute Pub Date : 2025-01-01 DOI:10.1016/j.proci.2025.105854

Daniel Kretzler , Rishabh Puri , Björn Stelzner , Thorsten Zirwes , Fabian P. Hagen , Oliver T. Stein , Dimosthenis Trimis

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引用次数: 0

Abstract

In this study, non-premixed laminar ammonia/air flames are investigated using a custom-designed heated slot burner developed at KIT. This innovative setup enables investigations into ammonia decomposition and pollutant formation processes through in-situ diagnostics, numerical simulations, and global performance analyses, providing a unique dataset. Experiments are conducted at three oven temperatures (T = 1073 K, 1123 K, and 1173 K) and two thermal loads (0.2 and 0.6 kW) at a global equivalence ratio of

Φ = 1

. Inlet temperatures, as well as qualitative insights into NH*, NH₂*, and OH* along the flame are obtained using thermocouples and emission spectroscopy. To assess global combustion characteristics, gas analyzers measure exhaust species, including NO, NO₂, N₂O, NH₃, and O₂. The experimental setup is reconstructed in two dimensions for numerical simulations using an in-house OpenFOAM solver. Flame and emission characteristics are investigated for different operating conditions and chemical mechanisms. While experiments and simulations agree well regarding flame length, flame stability, and chemiluminescence profiles, some deviations in exhaust gas emissions remain. These are attributed to experimental uncertainty from the assumption of flow symmetry, boundary conditions, and uncertainty due to the choice of chemical reaction mechanism at elevated temperatures. Emissions are strongly influenced by oven temperature and flow velocity, with lowest NH₃, N₂O, and NO_x levels observed at high oven temperatures. The non-premixed configuration achieves NO_x emissions down to 335 ppmv at

Φ = 1

, significantly below values from premixed combustion, which typically exceed several thousand ppmv. Pathway analysis reveals that the investigated reaction mechanisms predict routes with different relative contributions to NO production, but provide similar trends for NO consumption. The results highlight the suitability of the platform for systematic ammonia combustion studies and the potential of non-premixed strategies for NO_x mitigation.

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加热槽式燃烧器稳定非预混氨火焰的实验与数值研究

在本研究中，使用KIT开发的定制设计的加热槽式燃烧器对非预混层流氨/空气火焰进行了研究。这种创新的装置可以通过现场诊断、数值模拟和全球性能分析来研究氨分解和污染物形成过程，提供独特的数据集。实验在三种烘箱温度（T = 1073 K、1123 K和1173 K）和两种热负荷（0.2和0.6 kW）下进行，整体等效比为Φ=1。入口温度，以及定性的见解NH*， NH2*，和OH*沿火焰获得使用热电偶和发射光谱。为了评估全球燃烧特性，气体分析仪测量废气种类，包括NO、NO2、N2O、NH3和O2。利用内部的OpenFOAM求解器在二维空间重构实验装置进行数值模拟。研究了不同操作条件和化学机理下的火焰和发射特性。虽然实验和模拟在火焰长度、火焰稳定性和化学发光剖面方面都很一致，但废气排放方面仍然存在一些偏差。这主要归因于流动对称假设的实验不确定性、边界条件的不确定性以及高温下化学反应机制选择的不确定性。排放受烘箱温度和流速的强烈影响，在烘箱高温下观测到的NH3、N2O和NOx水平最低。在Φ=1时，非预混燃烧的NOx排放量降至335 ppmv，大大低于预混燃烧的值，而预混燃烧通常超过数千ppmv。途径分析表明，所研究的反应机制预测了对NO产生不同相对贡献的途径，但对NO消耗提供了相似的趋势。研究结果强调了该平台对系统氨燃烧研究的适用性，以及非预混策略在减少氮氧化物方面的潜力。

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来源期刊

Proceedings of the Combustion Institute 工程技术-工程：化工

CiteScore

7.00

自引率

0.00%

发文量

420

审稿时长

3.0 months

期刊介绍： The Proceedings of the Combustion Institute contains forefront contributions in fundamentals and applications of combustion science. For more than 50 years, the Combustion Institute has served as the peak international society for dissemination of scientific and technical research in the combustion field. In addition to author submissions, the Proceedings of the Combustion Institute includes the Institute''s prestigious invited strategic and topical reviews that represent indispensable resources for emergent research in the field. All papers are subjected to rigorous peer review. Research papers and invited topical reviews; Reaction Kinetics; Soot, PAH, and other large molecules; Diagnostics; Laminar Flames; Turbulent Flames; Heterogeneous Combustion; Spray and Droplet Combustion; Detonations, Explosions & Supersonic Combustion; Fire Research; Stationary Combustion Systems; IC Engine and Gas Turbine Combustion; New Technology Concepts The electronic version of Proceedings of the Combustion Institute contains supplemental material such as reaction mechanisms, illustrating movies, and other data.