Purpose

The purpose of this paper is to advance the multiphysics analysis of helicopter rotors under icing conditions by coupling the iced rotor’s aerodynamics, analyzed by CFD, with the rotor’s structural characteristics, analyzed by CSD.

Design/methodology/approach

The current work introduces supercomputer-based computational approaches capable of assessing the impact of ice accretion on the aerodynamics, blade dynamics, vibrations and loading of a rotorcraft. The rigid and elastic motions of the blades are accounted for through a loose coupling of the flow solver to a multibody dynamics solver. The coupling framework allows for comprehensive aeroelastic simulations of iced rotors in hover and in forward flight.

Findings

The flow and structural modules were validated on a full helicopter configuration in forward flight using the ROBIN experimental model. The tip structural deflections were in very close agreement with the experimental measurements.

Research limitations/implications

The results of the CFD analyses are limited by the available experimental results they can be compared to. In dry air CFD, three-dimensional (3D) experiments occur first and CFD is then compared to them; in icing, the opposite is true: 3D experiments (if they are ever done, as they are very expensive) chase CFD and sometimes never occur.

Practical implications

This paper presents an outline of how CFD and computational stress dynamics (CSD) analyses can be linked and provides a toolbox for deeper investigation of the complex flows over helicopters operating under difficult in-flight icing conditions.

Social implications

More and more helicopters are designed to be able to operate in hostile environments such as rescuing and saving lives over the oceans or mountains, conditions under which icing encounters cannot be avoided.

Originality/value

A loosely coupled CFD/CSD framework that accounts for the rotor blades structural response to aerodynamic loading and ice accretion in hover and forward flight has been presented. This versatile and cost-effective framework provides a more accurate estimation of the helicopter rotor performance and its degradation due to icing encounters during the early design stages than traditional CFD tools.

中文翻译：

---

通过 CFD/CSD 耦合对结冰转子动力学进行建模

目的

本文的目的是通过将结冰旋翼的空气动力学（CFD 分析）与旋翼的结构特性（CSD 分析）相结合，推进结冰条件下直升机旋翼的多物理场分析。

设计/方法/途径

目前的工作引入了基于超级计算机的计算方法，能够评估积冰对旋翼飞机的空气动力学、叶片动力学、振动和载荷的影响。叶片的刚性和弹性运动通过流动求解器与多体动力学求解器的松散耦合来考虑。耦合框架允许对悬停和向前飞行的结冰转子进行全面的气动弹性模拟。

发现

使用 ROBIN 实验模型在向前飞行的完整直升机配置上验证了流动和结构模块。尖端结构偏转与实验测量结果非常一致。

研究局限性/影响

CFD 分析的结果受到可用于比较的可用实验结果的限制。在干空气 CFD 中，首先进行三维 (3D) 实验，然后将 CFD 与它们进行比较；在结冰中，情况恰恰相反：3D 实验（如果曾经做过，因为它们非常昂贵）追逐 CFD，有时永远不会发生。

实际影响

本文概述了如何将 CFD 和计算应力动力学 (CSD) 分析联系起来，并提供了一个工具箱，用于深入研究在困难的飞行结冰条件下运行的直升机上的复杂流动。

社会影响

越来越多的直升机被设计成能够在恶劣的环境中运行，例如在海洋或山区救援和拯救生命，在这些条件下无法避免遇到结冰。

原创性/价值

提出了一个松散耦合的 CFD/CSD 框架，该框架考虑了转子叶片在悬停和向前飞行中对气动载荷和积冰的结构响应。与传统的 CFD 工具相比，这种多功能且经济高效的框架可以更准确地估计直升机旋翼性能及其在早期设计阶段因结冰而退化的情况。