The main aim of the CA3ViAR project is the design of an Open-Test-Case Fan geometry that will develop instability mechanisms which are representative for UHBR fans of civil aircrafts and perform a comprehensive experimental investigation to measure aerodynamic, aeroelastic and aero-acoustic performance in a wide range of operational conditions.
The “special” low transonic fan, made of composite material, presenting aerodynamic (stall) and aeroelastic (flutter) instabilities in the operating conditions inside the PTF Wind Tunnel will generate high-resolution aerodynamic, aeroelastic and aeroacoustic experimental data, to be used to calibrate and validate numerical models, and to be finally disclosed under open access for the European scientific community. Therefore, it is expected that CA3ViAR will generate impacts at several levels, including Society and Environment.
Regarding the Societal and Environmental Impacts, the current concern for global warming is pushing the research on aeronautical engines toward highly efficient solutions and designs. Since the study of where losses in efficiency occur and how to reduce them is of prime interest, and of course this affects all the engine components including the fans, the impact of CA3ViAR is going to be far reaching. Creating an experimental data-base under open access aimed at improving methods and procedures for more accurate LTF for UHBR engines will find its implementation in the future commercial jet aircraft with a clear impact on business (cost reduction), environment (greener engines) and society (greener and more affordable technologies).
Experimental tests were performed in the Propulsion-Test-Facility (PTF) of the Institut für Flugantriebe und Strömungsmachinen (IFAS) of Braunschweig, Germany. The proposal CA3ViAR will target several objectives. Initially a literature review of the main issues affecting composite UHBR engine fans will be performed by the Technische Universität Braunschweig (TUB). The design of the Low-Transonic Fan (LTF) will be led by TUB with support from DREAM (an Italian SME) in terms of aerodynamic shaping as well as from Leibniz Universität Hannover (LUH) and IBK in terms of aeroelasticity and aeroacoustics. The LTF test article, to be mechanically designed by IBK, will be conceived in a way to experience aerodynamic and aeroelastic instabilities in an expected way during wind-tunnel operations. Manufacturing-related activities will be performed under IBK supervision through subcontracting to well-recognized manufacturer specialized in rotor blades and parts made of composite and metallic materials, while requirements for the test article integration will be provided by TUB, responsible of WT instrumentation and operations.
The execution of the experimental tests aimed at measuring fan instabilities (e.g. stall, flutter, etc.) will be performed by TUB with support from LUH. Unfortunately, due to unforeseen problems during the operation of the rotor, the tests needed to be stopped and a further damage analysis outside the project will be performed. Thus, the last technical phase planned, the calibration and validation of aerodynamic, aeroelastic and aero-acoustic models did not take place.
