# Advancements and Applications of Rim-Driven Fans in Aerial Vehicles: A Comprehensive Review
## 10 The Future Prospects of Rim-Driven Fans  
The future prospects of rim-driven fans (RDFs) hold great promise and potential for various industries, particularly in the aerospace and maritime sectors. In recent years, the maritime sector has witnessed the emergence of the shaftless rim-driven thruster (RDT) as a groundbreaking ship propulsion option, marking a significant step towards more efficient and eco-friendly vessel propulsion. With advancements in electrical rim drives and the commercial availability of RDT devices for both surface and underwater vessels, the maritime industry has already reaped the benefits of this innovative technology. Looking ahead, we can anticipate a continued growth in the adoption of RDTs in the maritime domain. The application of RDFs is not limited to marine transport; there is also great potential for their integration into automotive and aerospace sectors, albeit with some lag in development. As the cost of larger base forms, advancements in technology, and the necessary technical expertise become more accessible, RDFs are likely to play a more prominent role in these sectors. The utilization of electromagnetic-thermal-fluid-solid coupling in high-power RDFs, as evidenced in recent theoretical and experimental studies, further underscores the potential for more efficient and effective RDF designs in the future. These studies shed light on the intricate interplay between electromagnetics, fluid mechanics, structural dynamics, and thermodynamics in RDFs, paving the way for advanced and highly optimized RDF technology.  
In the aerospace sector, the future prospects of rim-driven fans also present exciting possibilities. As technology continues to evolve, the development of RDFs for aerospace applications is expected to gain momentum. The efficient and compact nature of RDFs can offer significant advantages in terms of propulsion systems for aircraft, drones, and other aerospace vehicles. Their potential to reduce noise and enhance efficiency is particularly appealing for the aviation industry, where environmental concerns and operational  
\begin{table}
\begin{tabular}{c c c c} \hline
**Year** & **Reference** & **Performance** & **Problem** \\ \hline
2006 & [PERSON] et al. [50] & The NASA conceptual design investigation centered on creating a levitated ducted fan (referred to as a rim-driven fan) with a diameter measuring 32 inches & While the study focused on the electromagnetic circuit design, it did not discuss structural, aerodynamic, or thermodynamic aspects such as loadings, blade aerodynamics, heat dissipation, and torque and speed control \\ \hline
2017–2021 & [PERSON] et al. [22; 25; 65; 101] & A design for a compressible fluid capable of achieving a weight-to-thrust ratio of one-to-one & Their suggested prototype featured a centerline bearing that disrupted the core flow, appearing similar to a traditional hub fan design in terms of aerodynamics. \\ \hline
2018 & [PERSON] et al. [67] & Low fidelity models of aircraft, fan, and motor to optimize the range of a specific aircraft & A design code shows larger machine radii, necessitating larger shells or housings around the propulsion system \\ \hline
2020 & [PERSON] et al. [23] & Aerodynamic and acoustic performance of RDFs, as well as a comparison of the frequency spectra, are plotted for both the fanless motor and the hubless fan & Several small and low-speed RDF prototypes \\ \hline
2021 & [PERSON] et al. [94] & The aerodynamic characteristics of an RDF were studied & Investigating the effects of four key parameters, including rotor disk height, number of blades, central hole radius, and blade root mounting angle \\ \hline
2022 & Duan, FL. [51] & A proposal for a small rim-driven fan jet engine is introduced to aid in VTOL and STOL for mid-sized and large airplanes & This is just a proposal and further development is needed. \\ \hline \end{tabular}
\end{table}
Table 1: Brief summary of aerospace-related works.