Development of Carbon Composite Blades within the Context of the Experimental Validation of a CFD-Based Design Tool for Contra-Rotating, Electric Fan Engines

Abstract

Electric propulsion systems have emerged as a disruptive technological approach towards achieving sustainable and climate-neutral aviation. To expand the operational envelope of such propulsion units in terms of altitude and velocity, an enclosing duct and counter-rotating rotors to enhance efficiency can be utilized. In this study, an iterative CFD-based design tool developed for these novel propulsion systems is utilized to design a reference engine, having a classic rotor–stator configuration. Being the key component of this propulsor, a manufacturing process for composite blades is presented. This effort aims to make state-of-the-art technology accessible to smaller research projects, promoting the widespread adoption of electric propulsion technology in the aviation sector. By experimental investigations of the blade elongation both in tensile tests and engine operation, measuring the tip clearance with a high-speed camera, this process could be validated to facilitate the transferability of research. Finally, the performance of the manufactured engine is measured by a five-hole miniature probe, not only in design point but also in off-design operation. The results indicate that a substantial reduction in discrepancies between initial specifications, subsequent CFD simulations, and experimental investigations compared to conventional design tools relying on empirical formulations can be achieved due to the CFD-based approach. This allows the CFD-based tool to be validated for designing scalable contra-rotating fan engines.