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.

摘要：

由风管及局部构件中气流所产生的气动噪声一直是空调风管系统面临的主要问题之一，在系统设计阶段对管件中的气动噪声进行准确的计算具有重要的工程意义。对比我国与其他国家指导规范中空调风管系统气动噪声计算的相关内容后，发现主要差异集中于三通管件处气动噪声的计算。为探究各计算方法的准确性，对三通管件的气动噪声进行了实验测试和数值模拟。通过实验研究发现《ASHRAE Handbook》中噪声算法所得结果与实测数据更为接近，由数值模拟也得到相似结果。同时，实验与模拟中均发现干管出口端噪声水平低于支管出口端，这与《ASHRAE Handbook》所述矛盾。故认为《ASHRAE Handbook》中三通气动噪声算法更准确，但其对干管出口端噪声的描述存在问题。

关键词: 声学, 空调系统, 气动噪声, 噪声计算, 三通, 数值模拟