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3D MUltidisciplinary tools for the Simulation of In-flight iCing due to High Altitude Ice Crystals

Periodic Reporting for period 1 - MUSIC-haic (3D MUltidisciplinary tools for the Simulation of In-flight iCing due to High Altitude Ice Crystals)

Reporting period: 2018-09-01 to 2020-02-29

Icing is a major hazard for aviation safety. Over the last decades an additional risk has been identified when flying in clouds with high concentrations of ice-crystals. In such conditions, it has been observed that ice accretion may occur on warm parts of the engine core, resulting in engine incidents such as loss of engine thrust, strong vibrations, blade damage, or even the inability to restart engines. Performing physical engine tests in icing wind tunnels being extremely challenging and expensive, the need for numerical simulation tools able to accurately predict ICI (Ice Crystal Icing) is urgent and paramount for the aeronautics industry, especially regarding the development of new generation engines (UHBR = Ultra High Bypass Ratio, CROR = Counter rotating Open Rotor, ATP = Advanced Turboprop) for which analysis methods largely based on previous engines experience may be less and less applicable.
The European research project MUSIC-haic has been conceived to fill this gap and has started in September 2018. MUSIC-haic brings together the main European research institutions working on icing modelling as well as engine manufacturers and aircraft manufacturers. The objectives of the project are to develop advanced ice crystal icing models, implement them in existing industrial 3D multi-disciplinary tools, and finally perform extensive validation of the new ICI numerical capability through comparison of numerical results with both academic and industrial experimental data.
The project is divided into 6 work-packages (WP), 4 technical ones (WP1 to WP4) and 2 other ones dedicated to management and dissemination. WP1 aims to provide missing experimental data for model development and validation. The objective of WP2 is to complete the development of a comprehensive set of models for ICI, building on previous projects outcomes and using WP1 experimental data. The aim of WP3 is to implement the new ICI into the partners’ existing 3D multi-disciplinary tools and to provide ready-to-run tools for WP4 final validation tests (not started yet).

During the first eighteen months of the project, experimental setups (as well as new post processing tools) have been developed or improved by the WP1 partners. The setups are now ready to run to produce the data expected by the modellers involved in WP2. Some experiments were carried out to measure rheological properties of the ice layer (apparent yield strength, water imbibition characteristic time scale) that are expected to be necessary inputs for the modelling of shedding phenomena. Regarding the investigation of impact, erosion and accretion phenomena, experiments were performed and a first set of results was recently delivered to the modellers. All the test setups and results are described in Deliverable D1.1 that will be made public in March 2021.

In the scope of WP2, new models have been developed for ice layer rheological properties, ice particle impact onto a rigid body, erosion rate, and ice accretion phenomena. These models have been implemented in the existing 2D numerical tools and numerical tests performed. The calibration and elementary validation of these models is still in progress. All these new models are presented in details in Deliverable D2.1 that will be made public in March 2021.

Concerning WP3, tools requirement have been specified and synthesized in a common report (deliverable D3.1) that has been released to all the partners and to the advisory board members. All the WP3 partners have also started to work on the preparation of their 3D multidisciplinary computational tools for the implementation of the new ICI models. For some partners, encouraging numerical tests have already been performed to assess that the updated 3D tools provide the expected results.
"To develop the new 3D ICI numerical capability, MUSIC-haic does not start from scratch, but benefits from many important existing building blocks:
o Physical models: HAIC sub-project 6, which was devoted to models and tools development, made significant progress in the understanding of physical phenomena controlling ice crystal icing and led to the creation of a first generation of ICI models. All these models were implemented in 2D numerical research tools for the purpose of empirical constant calibration and first level validation.
o ICI physics experimental database: To support the development of ICI models, extensive experimental activities were performed within the HAIC project and in parallel, in the scope of North American projects, by the CNRC and NASA. These complementary experimental investigations allowed a large database to be created.
o ICI industrial database: HAIC-HIWC flight tests permitted the characterization of high altitude ice crystals properties and the collection of data for quantifying probe installation effects. Within the HAIC project, ICI tests with a Pitot probe were performed as well in the French DGA icing wind tunnel. In parallel, full engine tests (with a Honeywell ALF 502 turbofan engine) were performed in NASA’s large IWT (Propulsion Systems Laboratory - PSL).

Since the beginning of the project, significant progress beyond this state of the art has already been achieved.
First, regarding the experimental investigation of ICI phenomena, microscopic experiments have been successfully performed on ice particle impact and ice layer characterization, and a first set of new data has been released to the modelers. In addition, a first series of promising experiments have been carried out in icing wind tunnels on ice accretion and heat transfer phenomena.
Concerning the development of new models, important achievements are the development of new impact and erosion models with a lesser empirical basis that the HAIC models, the development of an empirical model for the yield strength of an ice layer, and the basement for a new multilayer approach to account for ice crystal accretion inception, slushy ice accretion and conjugate heat transfer.
Last but not least, all partners have started to carry out in parallel the necessary developments in their internal multidisciplinary 3D computer tools, in order to prepare the implementation of the new ICI models.

In terms of potential impact of the project, the new ICI numerical capability will provide the European aeronautical industry with a tool to de-risk and optimize the design of new engines with breakthrough architecture, to optimize the efficiency of probes and their location on the nose and fuselage of aircraft, and to reduce the cost and duration of certification.

Note regarding the images attached: Two versions of the same picture are proposed (a 2x2 table with single images and the 1x4 version as one combined image) + legend. Feel free to choose from them, depending on how it goes along with the text flow.” Feel free to contact philippe.onera@onera.fr cc music-haic-arttic@eurtd.com in case of questions. Full legend applying to both pictures: ""Experimental investigation of the impact of an ice crystal onto a solid surface performed by Airbus CRT in Munich. a) and b): view of the impinging ice crystal - c) and d) Superimposed post-impact image sequences showing the creation of numerous small fragment"""
Experimental investigation of the impact of an ice crystal onto a solid surface performed by Airbus
xperimental investigation of the impact of an ice crystal onto a solid surface performed by Airbus C