DNS-driven development of predictive LES models for gas turbine emissions

DNS 驱动的燃气轮机排放预测 LES 模型的开发

• 批准号: 434872808
• 负责人: Professor Dr.-Ing. Heinz Pitsch
• 金额: --
• 依托单位: Institut für Technische Verbrennung (ITV)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/434872808?language=en
• 关键词: DNS; driven; development; predictive; LES

The reduction of pollutant emissions is one of the main challenges in the development of gas turbine combustors. In this context, large-eddy simulations (LES), can contribute to reducing development cost and accelerating development processes. Therefore, the aim of this project is the improvement of emission models for LES of both aeroengines and stationary gas turbines. The present proposal is for the second phase of a 2+2-year project. For aeroengines, the focus is on modeling of soot. After soot formation and oxidation have been investigated in the first project phase, a better understanding for the breakthrough of soot from rich to fuel-lean regions is intended in the second phase. Soot breakthrough occurs when, due to the high turbulence levels in aeroengines, turbulent eddies transport soot pockets from fuel rich regions through the flame to fuel lean regions fast enough that a complete oxidation of soot particles cannot take place. Current LES models cannot describe these events with sufficient accuracy, thus significantly underpredicting soot emissions. In this project, state of the art LES models available in the literature and developed in previous project phases will be extended to consider soot breakthrough phenomena. This will be done in a three-step process: 1) generation of a DNS data base for three different levels of soot breakthrough; 2) assessment of current models based on the DNS and development of model extensions considering soot breakthrough; 3) model validation via LES of a lab-scale jet flame configuration and of a full model combustor. In stationary gas turbines, carbon monoxide (CO) emissions will be investigated. The aim in this phase is to study the effect of the hydrogen (H2) addition to methane (CH4) on CO emissions and their modeling. Starting point is the importance of H2 as future energy carrier. Here, we will consider the addition of small amounts of H2 to natural gas as fuel in stationary gas turbines. Previous work has shown the ability of even small amounts of H2 to significantly reduce CO emissions as a result of the increased flame speeds. A series of DNS of turbulent combustion of CH4/H2 mixtures will be performed. The DNS data will be analyzed to extend the present CO model to adequately consider the effects of H2 addition. The full model will be used in the LES of two model combustion chambers and validated with experimental data. Funding for this project is requested jointly from the DFG and the FVV. While the two proposed work packages address pollutant formation in different environments, strong connections are given by the embedding of the work packages in the project support provided by industrial partners of the FVV. Similar modeling approaches and research methodologies will be used for the prediction of CO and soot, so that the joint model development can lead to a generic description of pollutant formation.

减少污染物排放是燃气轮机燃烧器发展的主要挑战之一。在这种情况下，大型模拟（LES）可以有助于降低发展成本和加速发展过程。因此，该项目的目的是改善航空发动机和固定燃气轮机的发射模型。本提案是针对2+2年项目的第二阶段。对于AeroEngines，重点是建模烟灰。在第一个项目阶段研究了烟灰形成和氧化后，对于第二阶段的烟灰突破，可以更好地理解烟灰的突破。烟灰突破发生在航空引起的湍流水平高，湍流的涡流从富含燃料的区域通过火焰传输烟灰袋到燃料稀疏区域足够快，以至于无法发生完全的烟灰颗粒氧化。当前的LES模型无法以足够的准确性描述这些事件，从而显着低估了烟灰的排放。在这个项目中，文献中可用的最先进的模型将扩展，以考虑烟灰突破现象。这将在三步的过程中完成：1）生成三个不同级别的烟灰突破的DNS数据库； 2）根据考虑烟灰突破的模型扩展的DNS和开发的当前模型的评估； 3）通过实验室规模的喷气火焰配置和完整型号燃烧器的LES模型验证。在固定的燃气轮机中，将研究一氧化碳（CO）排放。在此阶段的目的是研究甲烷（CH4）添加氢（H2）对CO排放及其建模的影响。起点是H2作为未来能源载体的重要性。在这里，我们将考虑将少量的H2添加到天然气中，作为固定燃气轮机中的燃料。先前的工作表明，由于火焰速度的提高，即使少量H2也能够显着降低CO排放。将执行一系列CH4/H2混合物的湍流燃烧。将分析DNS数据以扩展当前的CO模型，以充分考虑H2添加的效果。完整模型将用于两个模型燃烧室的LE，并通过实验数据进行验证。该项目的资金由DFG和FVV共同要求。尽管两个提议的工作包涉及在不同环境中污染物形成，但通过FVV工业合作伙伴提供的项目支持中的工作包的嵌入来给出牢固的联系。类似的建模方法和研究方法将用于CO和烟灰的预测，因此联合模型开发可以导致对污染物形成的一般描述。