Abstract
In order to minimize the wind noise generated by a Sirocco fan, it is most important to understand the details of the flow field about a Sirocco fan. As the shape of a Sirocco fan is very complicated, the flow patterns about a Sirocco has not been examined in detail. Recently, the authors of this study have succeeded in reducing the wind noise of a Sirocco fan more than 1dB by placing a blocking plate at 90 degree from the tongue of the scroll. Despite of the reduction of the wind noise, its mechanism has not been made clear and thus the further reduction may not be expected without the understandings of the changes in the flow field with the presence of a blocking plate. Presently, the flow field of a Sirocco fan with a blocking plate at various locations have been examined in detail by the spark tracing method.
