Aerodynamic design is a crucial aspect in the development of small high-pressure centrifugal fan equipment. Within this process, we typically place greater emphasis on selecting the shape of the impeller front disc. This is because the airflow at the impeller inlet transitions from axial to radial flow and continues to expand. Consequently, suboptimal design may lead to flow separation within the centrifugal fan impeller. For a considerable period, designers of small high-pressure centrifugal fans believed curved front discs outperformed conical ones. This preference stemmed from the longer arc of curved discs, which facilitates a smoother, more gradual transition in flow patterns beyond the inlet. Many high-performance fan blades incorporate this design. However, as blade sizes increase, the manufacturing complexity and cost of curved front discs rise significantly. To meet operational requirements, expensive spinning machines were often necessary during use. Yet in actual production, some oversized impellers simply could not be machined with such large arcs, forcing the use of conical front plates. In recent years, numerous small high-pressure centrifugal fans with conical front plates have demonstrated total pressure efficiencies exceeding 85%. Consequently, perceptions have gradually shifted. Particularly when comparing the overall performance of curved front plates versus similar conical front plates in small high-pressure centrifugal fans, results indicate both exhibit comparable high performance. Consequently, considering the ease of machining and lower cost of conical front discs, they may be prioritized in design. As illustrated above, small high-pressure centrifugal fans with conical front disc structures can achieve superior performance during structural design. Thus, we can make rational choices based on actual conditions in design work. New Concepts, Insights, and Methods in Aerodynamic Design of Shell-less Centrifugal Fans With the advancement of modern aerodynamic design methods for shell-less centrifugal fans, we have encountered new challenges during the development of high-performance fans, particularly through communication with frontline production management technicians. Simultaneously, the process of resolving these issues often generates fresh ideas and approaches, continuously driving the evolution of modern design methodologies. Next, we will briefly introduce the selection of aerodynamic design methods for airflow, aiming to deepen our understanding. The aerodynamic design of shell-less centrifugal fan equipment is primarily based on the design flow rate requirements provided by the user. Moreover, the default operating condition is set to achieve high efficiency under such conditions. However, analysis of actual applications reveals that the operating point for many shell-less centrifugal fan units does not align with the aerodynamic design flow rate. The deviation in direction and magnitude is related to the specific speed. Typically, fans with specific speeds below 27—commonly termed low-specific-speed fans—often exhibit flow rates exceeding the original design conditions. Moreover, the deviation becomes more pronounced as the specific speed of the shell-less centrifugal fan decreases. Fans with medium specific speeds generally operate close to their original design conditions. When the specific speed exceeds 55, the operating flow rate falls below the original design flow rate. For such scenarios, we can initially adopt a flow-based aerodynamic design approach when selecting the startup design method. That is, when designing shell-less centrifugal fans, flow design and total pressure aerodynamic design should be conducted reasonably according to different user requirements. While optimizing design performance, the non-design performance of shell-less centrifugal fan equipment should also be considered.