Is there a theoretical upper speed limit to jet drive?

Discussion in 'Boat Design' started by RatliffFranklin, Feb 1, 2007.

  1. RatliffFranklin

    RatliffFranklin Previous Member

    Is there a speed at which water would be entering the intake faster than the pump could expel it? Or is it just determined by available horsepower?
     
  2. jehardiman
    Joined: Aug 2004
    Posts: 2,477
    Likes: 198, Points: 63, Legacy Rep: 2040
    Location: Port Orchard, Washington, USA

    jehardiman Senior Member

    For a jet drive to produce thrust, the inlet velocity must always be less than the outlet velocity. There is a real limit caused by cavitation considerations which leads to a ram pressure issues which causes the inlet to jet diameters to vary in strange ways if you want to go faster.

    On the other hand there are some really quirky things you can do theoreticaly...such as a suction drive.
     
  3. RatliffFranklin

    RatliffFranklin Previous Member

    Suction Drive


    So in theory what might a suction drive look like? And what's the underlying principle?
     
  4. jehardiman
    Joined: Aug 2004
    Posts: 2,477
    Likes: 198, Points: 63, Legacy Rep: 2040
    Location: Port Orchard, Washington, USA

    jehardiman Senior Member

    Suction caused by the lower inlet pressure/higher velocity of a centrifugal impeller.
     

  5. RatliffFranklin

    RatliffFranklin Previous Member

Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.