Aerodynamic performance of ducted fans for large-scale electric propulsion aircraft under variable operating conditions.

This article focuses on the numerical investigation of the aerodynamic performance evolution of ducted fans in large-scale electric propulsion aircraft under variable operating conditions, specifically examining true airspeed (TAS), rotational speed (RS), and tip clearance size. It derives and validates a similarity criterion for ducted fans to enable accurate scaling from model to prototype, facilitating rapid and cost-effective design. Key findings include a quadratic relationship between thrust and RS, a linear decrease in thrust with increasing TAS, and a reduction in thrust with larger tip clearances due to increased tip leakage flows. The study also shows that while TAS and RS affect the applicability of the similarity criterion, tip clearance has negligible impact, supporting the criterion's use in early-stage ducted fan design for electric propulsion systems.