OPEN FAN VALIDATION FOR CARBON-FREE AIRCRAFTS (PANDORA)

开放式风扇的概念已经存在了几十年。它的高推进效率，加上消除机舱阻力和重量，一直吸引着取代高旁通比的导管风扇，减少二氧化碳和氮氧化物的排放。CS1和CS2项目也做了相关的努力来追求对转开式转子（CROR）的概念。虽然CROR还没有进入市场，但已经取得了将噪音水平降低到管道风扇水平的进展。开放式风扇表现出与管道风扇的几个不同之处，到今天，管道风扇是高度复杂的组件，积累了数十年的研究。OP概念及其产品之间的鸿沟太大，无法由一个演示者来弥补，因为错误的想法具体化可能会产生误导性的结论。涡轮机械模拟已经完善了几十年，对于缩小概念和产品的详细实现之间的差距至关重要。然而，开式转子加剧了现有的问题（例如，即使是小迎角，叶片与叶片之间的变化，二氧化碳和噪音排放之间的强耦合等）。此外，公开粉丝缺乏公开可用的数据或测试用例，这阻碍了研究人员验证他们的想法。CS2的首次全球评估报告称，在创新的TP 130 pax项目中，尽管飞行马赫数较低，但与上一代风管风扇相比，预期噪声降低了-9dB。本项目旨在获得用于中短程飞机的导流单风扇（USF）的相关噪声和性能实验数据，有两个目标。首先，确认大约5-10分贝的降噪是可以实现的，代价是风扇效率的轻微损失，其次，验证和扩大数值工具的范围。将建立一个包含项目关键结果的实验数据库，以解锁USF在SAF，氢气和混合动力发动机和飞机配置中的应用。

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.