The design of gas turbine combustors is an iterative process which is often limited by the available modelling tools. While high degrees of modelling accuracy have been achieved using high fidelity tools, these are computationally expensive and not appropriate for design space exploration. By contrast, reduced order models carry low computational expense, but cannot fully reconstruct the combustion problem which spans multiple branches of physics and is characterised by 3D phenomena. As a result, empirical correlations are often relied upon, but these limit the designer to a narrow range of validity, preventing the exploration of novel design solutions.

To facilitate the design of new low emissions combustors, for which empirical models are not valid, a multi-fidelity design process has been followed. In this process, physics-based low order models are built; calibrated by high fidelity simulations and then used in multi-objective optimisation studies. This provides detailed insight early in the design process, leading to more fruitful optimisation studies and a shorter design cycle. This approach has been successfully demonstrated on other turbomachinary sub-systems, but has not yet been applied to combustors using publicly available methods.

In the current work, the multi-fidelity design process is demonstrated on the design and analysis of an impingement/effusion cooling layout for a lead direct injection combustor liner. A novel mutli-fidelity methodology was followed which used only publicly available methods. By following this approach, an indication of liner wall temperature distributions could be obtained very early in the design process, prior to any prototyping or testing. As such, applying a mutli-fidelity design approach to gas turbine combustors was shown to be both feasible and beneficial.

The results from the high fidelity simulations were compared to those of the low order model, revealing a number of discrepancies due to physics not captured - most notably a strong interaction between the swirling flow and liner wall. These detailed interactions resulted in failure of the initial cooling layout, leading to the liner exceeding its limit temperature by 10%. Inclusion of models to predict these phenomena have been recommended to improve the low order code fidelity. In doing so, the multi-fidelity modelling loop will be closed, yielding a more capable design code to be used for executing design space exploration.

燃气轮机燃烧器的设计是一个迭代过程，通常受可用的建模工具限制。尽管使用高保真度工具已经达到了很高的建模精度，但是这些工具在计算上昂贵并且不适用于设计空间探索。相比之下，降阶模型的计算费用较低，但无法完全重建跨越物理多个分支且以3D现象为特征的燃烧问题。结果，经常依赖于经验相关性，但是这些将设计者限制在狭窄的有效范围内，从而阻止了对新颖设计解决方案的探索。

为了简化经验模型无效的新型低排放燃烧器的设计，遵循了多保真度设计过程。在这个过程中，建立了基于物理学的低阶模型。通过高保真度模拟进行校准，然后用于多目标优化研究。这可以在设计过程的早期提供详细的见识，从而导致更富有成效的优化研究和更短的设计周期。这种方法已经在其他涡轮机子系统上得到了成功证明，但尚未使用公开可用的方法应用于燃烧器。

在当前工作中，通过对铅直喷燃烧室衬套的冲击/排放冷却布局进行设计和分析，演示了多保真度设计过程。遵循了一种新颖的多保真方法，该方法仅使用公开可用的方法。通过采用这种方法，可以在进行任何原型设计或测试之前的非常早的设计过程中获得衬里壁温度分布的指示。这样，将多保真设计方法应用于燃气轮机燃烧器被证明是可行和有益的。

高保真度模拟的结果与低阶模型的结果进行了比较，揭示了由于物理现象而未被捕获的许多差异-最显着的是旋流与衬管壁之间的强烈相互作用。这些详细的相互作用导致初始冷却布局失败，导致衬套超出其极限温度10％。建议使用包含预测这些现象的模型来改善低阶代码保真度。这样，将关闭多保真建模循环，从而产生功能更强大的设计代码，用于执行设计空间探索。