CORDIS - EU research results


Project description

Filling the gaps: experimental and numerical data supporting open fan concepts

Expanding urbanisation and increasing air travel mean more people are living in the vicinity of busy airports and noise is an important concern. Open fan engine concepts could reduce weight and emissions relative to conventional ducted fans, but they may be noisier. Further, the experimental data and modelling tools available to evaluate and refine open fan designs and reduce noise generation are limited. The EU-funded PANDORA project will address this gap with experimental data and advanced models. The team will collect experimental noise and performance data from an unducted single fan for short/medium-range aircraft. The data will also help validate and expand the scope of numerical tools to improve further analysis.


The open fan concept has been around for decades. Its high propulsive efficiency combined with the elimination of the nacelle drag and weight has been always appealing to replace high by-pass ratio ducted fans and reduce CO2 and NOx emissions. The CS1 and CS2 programs have made relevant efforts to pursue the contra-rotating open rotor (CROR) concept as well. Though CROR has not made it to market, progress has been done reducing noise levels to that of ducted fans.

Open fans exhibit several differences with respect to ducted fans which by today are highly sophisticated components accumulating decades of research. The chasm between the OP concept and its product is too big to be covered by a single demonstrator since a wrong materialization of the idea can give rise to misleading conclusions.

Turbomachinery simulations have been perfected for decades and are essential to close the gap between the concept and the detailed implementation of the product. However, open rotors exacerbate existing problems (e.g. blade-to-blade variations even for small angles of attack, strong coupling between CO2 and noise emissions, etc.). Moreover, open fans lack publicly available data or test cases preventing researchers from validating their ideas.

The first global assessment of CS2 reported an expected noise reduction of -9dB in the innovative TP 130 pax project with respect to the last generation of ducted fans though at a lower flight Mach number. This project aims to obtain relevant noise and performance experimental data of an unducted single fan (USF) for the short/medium-range aircraft with two objectives. Firstly, confirm that about 5-10 dB noise reduction is achievable at the expense of a slight penalty in fan efficiency, and secondly, validate and expand the scope of numerical tools. An experimental database with the key results of the projects will be built to unlock the application of the USF for SAF, Hydrogen, and Hybrid-electric engine and aircraft configurations.


Net EU contribution
€ 2 451 250,00
28040 Madrid

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Comunidad de Madrid Comunidad de Madrid Madrid
Activity type
Higher or Secondary Education Establishments
Total cost
€ 2 451 250,00

Participants (4)

Partners (1)