Acoustic-Based Predictive Maintenance and Performance Improvement of Industrial Fans

Industrial Fans (axial, centrifugal, mixed-flow, etc.), provide large volumetric flow and pressure generation, which are essential parts of ventilation and process systems. This review is a compilation of recent developments in fan design, performance and applications. The flow/pressure ranges and the efficiency (backward-inclined centrifugal can be as high as ~82- 90% efficient, while radial/blade fans are less efficient) are used to compare fan types. Currently, aerodynamic modelling (CFD) is regularly used in conjunction with experiments to optimize designs for blades and casings, for instance in the cement business, a redesign based on CFD reduced power consumption by 26-34%, and efficiency by up to ~20%, representing hundreds of MWh saved each year. Noise and vibration are still active research fields, as passive noise control (silencers, enclosures, innovative blade shapes) and active control strategies are surveyed, as well as standards for noise and vibration (ISO/AMCA). Advanced impeller technology and variable speed drives help to improve energy efficiency. Complex blade geometries are made possible using fan materials (high strength steels, composites) and advanced manufacturing (3D printing). There is a strong focus on maintenance and reliability with acoustic-based edge monitoring (e.g., on- device ML using the sound of the fan) as an alternative to the traditional vibration monitoring. There are gaps in green building regulations and integration with digital, and current standards (AMCA, ISO) cover fan testing and classification. Applications include HVAC, industrial process, power plants and others and energy usage and noise emissions are linked to environmental impacts. The future directions involve AI- driven control and diagnostics, bio-inspired aeroacoustics, sustainable materials and high-fidelity digital twins.