Patent attributes
A serial axial fan unit includes a first axial fan arranged to rotate about a central axis, a flow control device connected to the first axial fan along the central axis, and a second axial fan connected to the flow control device along the central axis. The flow control device preferably includes a wind tunnel portion, a base portion, and a plurality of flow control vanes. A flow of air caused by rotation of first blades has a whirl velocity component in substantially the same direction as the rotation direction thereof. This whirl velocity component is converted to a velocity component in a direction parallel or substantially parallel to the central axis by interference of first stationary vanes. The above arrangement provides an improvement in air volume characteristics of a serial axial fan unit including two axial fans arranged in series.
