| 摘要 |
<p>A water jet propulsion unit intended for use in jet boats, the unit comprising an intake section (10), a pump section (12) and a nozzle section (16). In the pump section (12) there are two counter-rotating impellers (14, 15) on concentric counter-rotating shafts (26, 27) calibrated so that any radial flow created in the upstream impeller (14) is converted into axial flow by the downstream impeller (15). In one embodiment the nozzle section (16) has a throttled outlet (17) to allow for a high mass/low pressure operation while maintaining pump priming. There are no support structures or stators downstream of the intake section (10) in the preferred embodiment.</p> |
