| 摘要 |
<p>A fluid dispersal device utilizes the Karman vortex street phenomenon to cyclically oscillate a fluid stream before issuing the stream in a desired flow pattern. A chamber has an inlet and outlet with an obstacle or island disposed therebetween to establish the vortex street. The vortex street causes the stream to be cyclically swept transversely of its flow direction in a manner largely determined by the size and shape of the obstacle relative to the inlet and outlet, the spacing between the obstacle and the outlet, the outlet area, and the Reynolds number of the stream. depending on these factors, the flow pattern of the stream issued from the outlet may be either: a swept jet, residing wholly in the plane of the device and which breaks up into droplets solely as a result of the cyclic sweeping, the resulting spray pattern forming a line when impinging on a target; or a swept sheet, the sheet being normal to the plane of the device and being swept in the plane of the device, the resulting pattern containing smaller droplets than the swept jet pattern and covering a two-dimensional area when impinging upon a target. A particular feature of the device is that it is moulded in one single piece from synthetic plastics material, the obstacle or island being an integral part of the single-piece moulding.</p> |
