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繁體中文Fan Selection and Optimization
11/21/2025Fans, as core equipment for achieving airflow and pressure regulation in industrial and civil fields, have their type selection directly related to operating efficiency, noise control, and space adaptability. Axial, mixed-flow, and centrifugal fans each possess unique technical characteristics and demonstrate distinct advantages in different scenarios, while the required air pressure is the core basis for determining the type of fan needed.
Our core demand for fans is always to efficiently complete air transport and pressure generation while ensuring optimal efficiency and minimum noise. Compared to other air handling equipment, fans are the preferred solution in many scenarios due to their continuous and stable airflow output, compact space occupation, and simple component structure. To accurately determine which type of fan—centrifugal, axial, or mixed-flow—is best suited for a specific application, it is first necessary to deeply understand the basic operating principles of each type of fan.
Air Pressure: The Core Criterion for Fan Type Selection
The core principle of axial fan operation is to convert the axially drawn airflow into a spiral flow pattern through the blades, thereby increasing the total pressure. Theoretically, to obtain higher pressure, the flow angle of the airflow towards the rotating blades needs to be increased, but this method has inherent limitations: when the relative flow angle exceeds a reasonable range, the aerodynamic efficiency will significantly decrease, and the airflow separation phenomenon will intensify, leading to a significant increase in operating noise.
When the application scenario requires high pressure, relying solely on the aerodynamic characteristics of the blades is insufficient. At this point, the role of centrifugal force becomes particularly crucial. In fact, all fans are rotating systems, and the airflow is always affected by centrifugal force during operation. However, in axial fans, except when operating at their optimal operating point, most of the airflow flows in a centrifugal direction. This swirling airflow directly hinders the normal transport of gas, making it unsuitable for high-pressure scenarios.
For high-pressure applications, centrifugal fans are the optimal choice—in the pressure accumulation process of centrifugal fans, centrifugal force plays a key, and in some cases, even dominant role. Based on the characteristics of the three types of fans, a clear selection direction can be determined:
Axial fans: Suitable for low-pressure, high-airflow applications, such as ventilation in large factories and cooling towers;
Centrifugal fans: Suitable for high-pressure, low-airflow applications, such as industrial dust removal systems and boiler induced draft;
Mixed-flow fans: Suitable for medium-pressure, medium-airflow applications, such as shopping mall fresh air systems and subway tunnel ventilation.
CFD Simulation: A Modern Tool for Fan Optimization Design
In the traditional stage of fan design, experimental methods were the mainstream approach. The design process relied on a large number of physical tests, which were not only time-consuming and labor-intensive but also difficult to accurately capture the details of the flow field. Now, with the maturity of computational fluid dynamics (CFD) technology, it has been fully integrated into the fan aerodynamic design process, becoming a core tool for improving design efficiency and accuracy.
The application scenarios of CFD technology are extremely wide-ranging. Whether it's airflow optimization in various heat and mass exchange systems, the overall design of a brand-new fan, or the performance improvement of key components such as blades and blade tips, all can be achieved through CFD. Compared with traditional physical experiments, numerical experiments are not only more convenient and less costly but also allow for detailed analysis of the flow field, clearly showing the flow trajectory and pressure changes of the airflow inside the fan.
With the help of CFD fluid simulation, designers can gain a deep understanding of the blade performance at each operating point, accurately identify energy loss points and noise sources, and analyze the interaction mechanism between the fluid and the equipment walls, providing data support for optimized design. In the current trend of pursuing cost-effective solutions, aerodynamicists can significantly shorten the design cycle using CFD, for example, by simulating and optimizing the curvature and twist angle of fan blades and designing special blade tip structures to achieve performance breakthroughs. More importantly, CFD technology supports "on-demand customization"—it allows for the direct design of dedicated fans for specific application scenarios based on the required air pressure and airflow, rather than adapting existing fans, significantly improving the compatibility between the fan and the application.
With the successful application of CFD technology in fan design, the role of physical experiments has also changed: from the past "basic design method" to the current "necessary verification and confirmation method". Its core function is reflected in two aspects: firstly, it provides final verification of the overall performance of the fan (such as airflow, pressure, and efficiency) to ensure compliance with design specifications; secondly, it verifies whether the performance of key components such as guide vanes and downstream diffusers meets the standards, and eliminates potential problems that may affect overall operation, providing a double guarantee for the stable operation of the fan.
In summary, selecting the appropriate fan hinges on aligning its pressure-airflow capabilities with application needs, with axial, mixed-flow, and centrifugal fans each dominating their respective niches. The adoption of CFD simulation has revolutionized fan design, moving beyond trial-and-error to precise, efficient customization while leveraging physical experiments for validation. As industrial and civil demands for energy efficiency and performance grow, mastering this synergy of selection criteria and simulation tools will remain crucial for unlocking the full potential of fan systems, driving innovation and reliability across sectors.
