关键词: 烧结金属丝网声衬, 穿孔板声衬, 声学流管实验台, 直接提取法, 线性声衬, 掠流声阻抗

Abstract:

The sintered wire mesh liner， as a new aeronautical linear liner， is proposed. A grazing flow experiment is conducted on a flow duct set up using the straightforward method， which adopts an appropriate incident sound pressure level to exclude the high sound intensity effect， and a conventional perforated liner， a wire mesh perforated liner， and a sintered wire mesh liner are tested. This experiment shows that， for the conventional perforated liner， the grazing flow acoustic resistance at low frequencies and the grazing flow acoustic reactance at high frequencies exhibit significant increase and decreases as the flow velocity increases， respectively. As for the wire mesh perforated liner， this trends suppressed to some extent but still exists. However， the sintered wire mesh liner， which departs from the traditional perforated plate structure and uses sintered wire mesh as its liner panel， enhances its viscous acoustic resistance. As a result， both the resistance and reactance due to the grazing flow effect change very little within the tested flow velocity range. This liner offers superior linearity in response to grazing flow and is more consistent with the trend of the optimal acoustic impedance for aeroengine bypass backward noises.

Key words: sintered wire mesh liner, perforated liner, acoustic flow duct setup, straightforward method, linear liner, grazing flow acoustic impedance