Purpose

The exponential growth in computational capabilities and the increasing reliability of current simulation tools have fostered the use of computational fluid dynamics (CFD) in the design of pioneering aircraft engine architectures, such as the counter rotating open rotor (CROR) engine. Today, this design process is led by tight performance and noise constraints from a very early stage, thus requiring deep investigations of the aerodynamic and acoustic behaviour of the fluid flow. The purpose of this study is to track the trajectory of tip vortices, which is of critical importance to understand and prevent potential vortex–blade interactions with subsequent rows, as this condition strongly influences the aerodynamic and structural performance and acoustic footprints of the engine.

Design/methodology/approach

In this paper, a flow feature detection methodology is applied to a particular CROR test case with the goal of visualizing and tracking the development of these coherent structures from the tip of front rotating blades. The suitability and performance of four typical region-based methodologies and one line-based (LB) criteria are firstly evaluated. Then, two novel seeding methodologies are presented as an attempt to improve the performance of the LB algorithm previously investigated.

Findings

It was demonstrated that the new seeding algorithms increase the probability of the selected seeds to grow into a tip vortex line and reduce the user’s dependence upon the selection of candidate seeds, providing faster and more accurate answers during the design-to-noise iterative process.

Originality/value

Apart from the new vortex detection initialization methodologies, the paper also attempts to assist the user in the endeavour of extracting rotating structures from their own CFD simulations.

中文翻译：

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CROR发动机上旋涡轨迹和旋涡-叶片相互作用的数值预测

目的

计算能力的指数级增长和当前模拟工具的可靠性不断提高，已在诸如反旋转开放式转子（CROR）发动机等开创性飞机发动机架构的设计中促进了计算流体动力学（CFD）的使用。今天，这种设计过程从很小的时候就受到严格的性能和噪声限制，因此需要深入研究流体的空气动力学和声学特性。这项研究的目的是跟踪尖端涡旋的轨迹，这对于理解和防止潜在的涡旋叶片与后续排的相互作用至关重要，因为这种情况会严重影响发动机的空气动力和结构性能以及声学足迹。

设计/方法/方法

本文将流特征检测方法应用于特定的CROR测试用例，目的是从前旋转叶片的尖端可视化并跟踪这些相干结构的发展。首先评估了四种典型的基于区域的方法和一种基于行的（LB）标准的适用性和性能。然后，提出了两种新颖的播种方法，以尝试改善先前研究的LB算法的性能。

发现

事实证明，新的播种算法增加了所选种子长成尖端涡流线的可能性，并减少了用户对候选种子选择的依赖性，从而在“设计-噪声”迭代过程中提供了更快，更准确的答案。

创意/价值

除了新的涡流检测初始化方法外，本文还尝试帮助用户从自己的CFD仿真中提取旋转结构。