Axial fans are widely employed in ventilation and air-conditioning systems, yet the associated noise pollution remains a significant challenge. This study investigates the influence of leading-edge modifications on the aerodynamic performance and noise characteristics of an axial flow fan utilized in building ventilation. Three types of leading-edge obstacles, including tetrahedral, hemispherical, and semi-cylindrical, were applied to the fan blades, and their impact was assessed through numerical simulations using FLUENT, incorporating turbulence and broadband acoustic models. The results reveal that leading-edge obstacles can effectively reduce noise by mitigating trailing-edge vortex shedding, improving airflow stability, and decreasing pressure pulsations and noise frequency amplitudes near the impeller root. Among the tested configurations, attributed to the enhanced airflow uniformity and minimized aerodynamic interference, the semi-cylindrical obstacle exhibited superior performance in noise reduction, particularly at the fan outlet where the maximum sound power level is reduced by 12.4 %. Limited experimental noise measurements were performed to confirm the noise reduction. This study provides valuable insights into the design of low-noise fan blades for building ventilation systems, highlighting the potential of leading-edge modifications to achieve substantial noise reduction without compromising aerodynamic efficiency.

中文翻译：

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前沿障碍物对建筑通风用轴流风机流场和噪声的影响

轴流风机广泛用于通风和空调系统，但相关的噪音污染仍然是一个重大挑战。本研究调查了前沿修改对用于建筑通风的轴流风机的空气动力学性能和噪声特性的影响。对风扇叶片应用了三种类型的前沿障碍物，包括四面体、半球形和半圆柱形，并使用 FLUENT 进行数值模拟，结合湍流和宽带声学模型，评估了它们的影响。结果表明，前沿障碍物可以通过减轻后缘涡旋脱落、提高气流稳定性以及减少叶轮根部附近的压力脉动和噪声频率幅度来有效降低噪声。在测试配置中，由于增强的气流均匀性和最小的空气动力学干扰，半圆柱形障碍物在降噪方面表现出卓越的性能，特别是在风扇出口处，最大声功率级降低了 12.4 %。进行了有限的实验噪声测量以确认噪声降低。这项研究为建筑通风系统用低噪音风扇叶片的设计提供了有价值的见解，突出了前沿修改的潜力，可以在不影响空气动力学效率的情况下实现大幅降噪。