Development of ultra-compact combustors for low-carbon technology using trapped vortex concepts

利用驻涡概念开发用于低碳技术的超紧凑燃烧器

• 批准号: EP/T028084/1
• 负责人: Ivan Langella
• 金额: $ 13.62万
• 依托单位: Delft University of Technology
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FT028084%2F1
• 关键词: Development; ultra; compact; combustors; low

Energy demand will be up by more than a quarter by 2040 [International Energy Agency data]. Given the dominance of combustion in meeting this demand, it is imperative to develop low-carbon, efficient gas turbine (GT) engines to reduce emissions impact and tackle the global warming as set by the Paris Agreement. In recent years lean premixed technology has attracted interest due to its potential of reduced emissions and high efficiency. However, lean combustion is prone to instabilities that may lead to unwanted oscillations, flame extinctions and flashbacks. Use of low or zero-carbon fuels like hydrogen is also limited because the high speeds needed to prevent flashbacks due the high low-heating values (LHV) can destabilise the vortex dynamics. Further development is thus required to achieve better efficiency and lower emissions, and effective flame holding techniques are crucial for this development. In ultra-compact combustor design, trapped vortex (TV) systems are implemented either in the primary zone or in the inter-turbine region to increase the resident time of combusting gases, resulting in better mixing, thus higher efficiency and lower emissions. Higher resident times also imply a shorter combustor, thus a lighter engine and less fuel consumption, also helping the process of hybridisation in multi-cycle devices. TV are locked stably within a cavity and thus are less sensitive to external disturbances even at high speeds, allowing use of low or zero-carbon fuels with high LHV like hydrogen. However, the process of flame stabilisation is rather complex because of the shear and boundary layer (BL) vortex dynamics, the strong heat transfer to the wall and the simultaneous occurrence of flame propagation and auto-ignition processes. The effective control of the flame dynamics requires a deep understanding of these processes.This project aims to develop improved understanding of the fundamental processes governing flame stabilisation in TV systems for ultra-compact combustion design, and their potential to deliver improved flame stability and low emissions at high speed (subsonic) conditions in the context of lean premixed technology. In particular, the TV physics will be studied i) in presence of a radially accelerating flow representing the swirled flow dynamics at the entrance of the combustion chamber; and ii) in presence of an axially accelerating flow when the cavity is located within the converging duct near the combustor exit. Both swirled and axial acceleration can destabilise the vortex dynamics, so this dynamics has to be understood before TV systems can be effectively employed. The analyses will be conducted through high-fidelity large eddy simulations (LES), which represents a cost-effective tool as compared to expensive experimental investigations. In this way the effect of turbulence, equivalence ratio and cavity geometry can be explored in details via parametric study. Moreover, the performance of different alternative fuels and their implication in terms of flame holding and model performance can be evaluated for different TV designs. An improved model involving presumed PDF approaches based on mixed flamelets/perfectly stirred reactor will be developed to account for the aforementioned physics. The fundamental understanding for this development will be extracted from unprecedented detailed direct numerical simulation (DNS) and by using validation data from experiments provided by the project partners.The outcomes of this project will significantly help the development of modern, low-carbon engines, and improve the understanding of the fundamental physics within these devices. Moreover, the project will lead to the development of CFD codes and models that can be used in industrial design cycles. Thus, this project is timely and strongly relevant for leading UK industries such as Rolls-Royce and other emerging industry, and will help them to maintain their leading role in the power-generation sector.

到2040年，能源需求将超过四分之一[国际能源机构数据]。鉴于燃烧在满足这一需求中的主导地位，必须开发低碳，有效的燃气轮机（GT）发动机，以减少排放量的影响并解决《巴黎协定》设定的全球变暖。近年来，精益预处理的技术由于其排放降低和高效率而引起了兴趣。但是，精益燃烧容易导致可能导致不必要的振荡，火焰灭绝和闪回的不稳定性。由于高加热值（LHV）可能会破坏涡旋动力学的稳定性，因此使用低或零碳燃料（如氢）也受到限制。因此，需要进一步的发展以提高效率和降低排放，而有效的火焰持有技术对于这一发展至关重要。在超紧凑型燃烧器设计中，在主要区域或涡流区域中实现了捕获的涡流（TV）系统，以增加燃烧气体的居民时间，从而获得更好的混合，从而更高的效率和较低的排放。较高的居民时间也意味着较短的燃烧器，因此发动机更轻，燃油消耗较少，也有助于多循环设备中的杂交过程。电视稳定地锁定在空腔内，因此即使在高速下也对外部干扰也不太敏感，从而可以使用具有高LHV（如氢）的低或零碳燃料。但是，由于剪切和边界层（BL）涡流动力学，强烈的热传递到墙壁以及同时出现火焰传播和自动点火过程，因此火焰稳定过程非常复杂。火焰动态的有效控制需要对这些过程有深入的了解。该项目旨在对电视系统中的火焰稳定的基本过程有了改进的了解，以实现超紧凑型燃烧设计，并在精益预选技术的情况下，在高速（subsonic）条件下提供改进的火焰稳定性和低速度（subsonic）条件的潜力。特别是，将研究电视物理学i）在存在径向加速的情况下，代表燃烧室入口处旋转的流动动力学； ii）在轴向加速的情况下，当腔位于燃烧器出口附近的融合管内时。旋转和轴向加速度都可能破坏涡旋动力学的稳定，因此必须在有效地使用电视系统之前了解此动态。分析将通过高保真大型涡流模拟（LES）进行，该模拟代表了一种具有成本效益的工具，与昂贵的实验研究相比。通过这种方式，可以通过参数研究详细探讨湍流，等效比和空腔几何形状的影响。此外，可以评估不同替代燃料的性能及其在火焰保持和模型性能方面的影响。将开发涉及基于混合燃料/完全搅拌反应器的推测PDF方法的改进模型，以说明上述物理学。对这项开发的基本理解将从前所未有的详细直接数值模拟（DNS）中提取，并使用项目合作伙伴提供的实验的验证数据。该项目的结果将大大有助于开发现代，低碳发动机，并改善对这些设备中基本物理学的理解。此外，该项目将导致可以在工业设计周期中使用的CFD代码和模型的开发。因此，该项目与劳斯莱斯（Rolls-Royce）和其他新兴行业等英国领先的行业及时且密切相关，并将帮助他们在发电部门保持领先作用。

项目成果

LES/THICKENED FLAME MODEL OF REHEAT HYDROGEN COMBUSTION WITH WATER/STEAM INJECTION

注水/蒸汽再热氢燃烧的 LES/加厚火焰模型

• 发表时间: 2023
• 作者: Kruljevic B.

A-priori and a-posteriori analysis of flamelet modelling for large-eddy simulations of a non-adiabatic backward-facing step

用于非绝热后向台阶大涡模拟的火焰模型的先验和后验分析

• 发表时间: 2023
• 作者: Kruljevic B.

A priori and a posteriori analysis of flamelet modeling for large-eddy simulations of a non-adiabatic backward-facing step

• DOI: 10.1063/5.0141108
• 发表时间: 2023-05
• 期刊: Physics of Fluids
• 影响因子: 4.6
• 作者: B. Kruljević;N. Doan;P. Breda;M. Pfitzner;I. Langella

DIFFERENTIAL DIFFUSION MODELLING OF A LIFTED H2 FLAME IN VITIATED COFLOW USING LES-FLAMELET APPROACH

使用 LES-FLAMELET 方法对污染的 COF 中升高的 H2 火焰进行微分扩散建模

• 发表时间: 2023
• 作者: Ferrante G.

NOx emissions trends in hydrogen lean premixed flamelets at high strain rate

• 发表时间: 2022-07
• 作者: Alessandro Porcarelli;B. Kruljević;I. Langella