日本機械学会論文集B編
Online ISSN : 1884-8346
ISSN-L : 1884-8346
一般論文
多翼送風機の非定常流れと空力騒音発生メカニズムに関する研究
川埼 真俊平原 裕行中村 匡徳
著者情報
ジャーナル フリー

2013 年 79 巻 804 号 p. 1571-1582

詳細
抄録

A aerodynamic noise problem in an automotive air-conditioning multi-blade blower was investigated numerically. The preceding measurements of the noise from a multi-blade blower demonstrated that the noise having a peak at 60 and 110 Hz was generated when it was operated at a low flow rate (φ=0.09), whereas the noise broadly ranged from 400 to 800 Hz was detected for a high flow rate (φ=0.22). In order to investigate the aerodynamic mechanism that generates these noises, flow in the multi-blade blower was numerically studied with large eddy simulation. The results showed a large pressure fluctuation at the tongue in the low flow rate. Observing the flow near the tongue, it was found that a re-circulated flow from the scroll terminal collided with specific point on the tongue surface and an excited oscillatory flow was issued periodically. Due to this flow behavior, it was postulated that the noise at 60 and 110 Hz for the low flow rate condition was induced by the flow impingement against the tongue related to the self-excited oscillation. In contrast, for the high flow rate, a prominent pressure fluctuation was found at the tongue and the blade surface of the shroud side. The flow visualization indicated that vortices shed from the trailing edge, interacted with a main stream and collided with the tongue. In addition, vortices in the shear layer which was formed behind the bell-mouth intermittently convected into a passage of the blades. These vertical interactions are considered to cause a large pressure fluctuation at the tongue and between the blades, thereby attributed to be the noise source in the high flow rate condition.

著者関連情報
© 2013 一般社団法人 日本機械学会
前の記事 次の記事
feedback
Top