WP1: The two first periods have allowed the partners to define and agree between Dassault Aviation and Saint-Gobain Sully the specifications, the trade-off matrix and the project organization. The work is completed.
WP2: Moreover they have allowed to make a State of the Art and review the latest emerging technologies in order to propose five improved window concepts (WP2). The five improved window concepts have been identified and formalized in the deliverable D2.1. Besides, M2 milestone has been passed in May 2019 with 3 months delay but it has allowed the partners to agree on the right entrance data for the next WP, I mean "Simulation" for mechanical optimisation. The work is completed in this WP.
WP3/WP4: Due to a lull in progress on WP3 , a small SGS resource was charged to coupons testing (WP4) within first PRs, consisting of: tools development and materials purchasing & structural bonding development (scheduled but not really initiated).
The Topic leader has taken the decision to put indefinitely on hold the activities of the WP3 and WP4 and focus on WP5 ones. An amendment of the Grant Agreement has been submitted at end of 2021 and validated by JU.
WP5: In Water Transport, the objective of the work led by USMB is the simulation of the water transport by droplets or film flows (resulting from the coalescence of several droplets) on a windshield in presence of a gas flow. The approach combines a mathematical modelling and the development of a numerical tool. The mathematical modelling relies on the elimination of the cross-stream coordinate (normal to the wall) with an appropriate averaging strategy (weighted residual method) which preserves the proprieties of the basic equation (consistency, hyperbolicity, conservative laws). Mathematical developments have been submitted in research papers.
SGS leads DA CFD Calculation with Regular work and follow-up on the physics of the phenomenon (SGS) in order to acquire a multi-physics digital calculation tool (integrating the water transport simulation developed by the Beneficiary) capable of defining the window heating power mapping in real flight conditions. Data has been provided by DA (calculation of shear stress, pressure coefficient & droplets collection yields in different environments and aircraft shape).
Finally, a model has been developed for the windshield design of average power requirement to keep windshield temperature above zero degrees to ensure permanent visibility. This has taken into account a parameter “wetness factor” to model the partial vaporization of water on windshield. This parameter is provided by Ad-hoc model from Icing Tunnel Test performed during the project. This model also considers local values of air temperature and velocity over the windshield to compute convection heat transfer.
This model has been used to run a thermal analysis on F7X design to propose an optimized heated windshield.
WP6: The principal activities linked to T6.1 were launched during the latter parts of the RP3. Since June/July discussions have been undertaken with Dassault focusing on the merits of a windshield proposing differentiated heating options versus a standard windshield. A design has been presented and validated during a Critical Design Review (CDR) in April 2022 (Milestone 5). This optimized windshield has a nominal power requirement 7% less than F7X baseline. Due to a specific work on windshield heat control (WHC), around 20% of energy savings are expected.
To validate this optimized Demonstrator, a test plan has been proposed. The test plan describes flight tests with stabilization phases (fixed operating conditions) in dry or icing conditions to measure heat transfer coefficient on windshield (validate model) and experience the optimized windshield in-flight.
WP7: The Demonstrator has been manufactured by SGS in 2022 and delivered to the Topic Leader in September of 2022. This Demonstrator is instrumented by thermal sensors to measure windshield temperature field in-flight. A second Demonstrator has been manufactured as a back up/ spare. Both Demonstrators are compliant with airworthiness and Design validated during CDR.
Flight tests were performed at beginning of 2023. More than 20 flights have been run. A comparison with the model in dry conditions has been delivered in the last deliverable of this WP. With a statistical analysis, there are some clues to confirm that model (with local values) is the most appropriate compared with basic averaged approach. All approaches seem to overvalue heat transfer (in particular, at high Reynolds number).
WP8: Project management (Technical, administrative, financial and risk analysis) and work coordination have been followed and reported to the Topic Manager
