Noise Control Measures for Backward-Curved Double-Inlet Centrifugal Fans

Noise Control Measures for Backward-Curved Double-Inlet Centrifugal FansThe noise generated by backward-curved double-inlet centrifugal fans is typically caused by friction and interference between the aerodynamic forces during operation and the surrounding environment. If the peripheral speed of the blades in a backward-curved double-inlet centrifugal fan is excessively high, the impact of airborne noise increases, and consequently, its proportion within the total noise level also rises. Linear velocity is the decisive factor for noise generation. Understanding this principle, it is essential to consider the significant impact of airborne noise on overall noise pollution when purchasing backward-curved double-inlet centrifugal fan units. So, how can airborne noise be reduced? For stable air pressure and flow rates, the following approaches can be considered to lower fan operating noise: First, pay attention to the airflow volume and direction of the backward-curved double-inlet centrifugal fan, experimenting with adjustments at the blade tips. Simultaneously, fan selection is a crucial solution. When choosing low-speed backward-curved blades, the operating point must be close to the fan's high-efficiency point. Second, to achieve better noise reduction, the backward-curved double-inlet centrifugal fan must be directly coupled to the motor. Additionally, the coupling connecting the fan and motor is an effective method for noise reduction. When indirect drive is required, a V-belt with no clearance between the motor and fan is necessary to minimize noise. Additionally, during the structural design process of the backward-curved double-inlet centrifugal fan assembly, the inlet and outlet are designed to be straight. To avoid increasing resistance noise generated when air flows toward the inlet and outlet, the design avoids abrupt bends. Simultaneously, using flexible connectors can reduce noise generated by the backward-curved double-inlet centrifugal fan due to airflow.