关键词: 声学, 空调系统, 气动噪声, 噪声计算, 三通, 数值模拟

Abstract:

The aerodynamic noise generated by a flow inside the ducts and components has always been one of the main problems in the field of HVAC system. It is of engineering significance to calculate the aerodynamic noise caused by duct elements accurately at the design stage. The contents of aerodynamic noise calculation for air duct systems in HVAC design manual of China is compared with those of other countries’ manuals, finding that the difference is mainly concentrated on the noise through branch take-offs. In order to explore the accuracy of each method, the experiments and numerical simulations of aerodynamic noise for branch take-off are carried out, finding that the result of branch duct noise from the method used in ASHRAE is closer to the measured data, which is identical with the circumstance of simulations. Meanwhile, the sound pressure level at outlet of main duct is both lower than that at branch in the experiments and simulations, indicating a contradiction with ASHRAE. Therefore, the method from ASHRAE is more accurate, but the description of noise at the outlet of main duct is incorrect.