What is the difference between impeller and propeller

Discussion in 'Surface Drives' started by Tracie Kaneshiro, Jul 1, 2020.

  1. Tracie Kaneshiro
    Joined: Jun 2020
    Posts: 1
    Likes: 0, Points: 1
    Location: USA

    Tracie Kaneshiro New Member

    An impeller is a rotating part of a centrifugal pump which transfers energy from the motor that drives the pump to the fluid pumped by accelerating the fluid outwards from the center of rotation.

    A propeller is a device with a rotating hub, that when rotated, performs an action that is similar to Archimedes' screw. It transforms rotational power into a linear thrust by acting upon a working fluid such as water.

    i think this the main diffrence between impeller and propeller
     
  2. gonzo
    Joined: Aug 2002
    Posts: 14,569
    Likes: 689, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    There are several types of impellers. Most boat engine impellers are flexible and work as a displacement pump. At higher speeds, some are design to transition into a different mode as centrifugal pumps. Jet drives also use impellers and are not centrifugal pumps.

    That is not quite right. Propellers are rotating foils operating on a fluid that can be considered incompressible within limits. An Archimede's screw operates inside a pipe, which is a very different condition.
     
  3. TANSL
    Joined: Sep 2011
    Posts: 6,238
    Likes: 301, Points: 93, Legacy Rep: 300
    Location: Spain

    TANSL Senior Member

    In other words, the device carried by planes powered by the so-called (misnamed?) "propellers" are not propellers because the fluid in which they operate is compressible.

    .
     
  4. gonzo
    Joined: Aug 2002
    Posts: 14,569
    Likes: 689, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    This is your usual nonsense. Please show any plane operating under water. :rolleyes:
     
  5. TANSL
    Joined: Sep 2011
    Posts: 6,238
    Likes: 301, Points: 93, Legacy Rep: 300
    Location: Spain

    TANSL Senior Member

    Now you have caught me, what a smart man you are! I can't find any examples of a submarine plane, I can only think of seaplanes that don't go under water but over water. But even those planes, which have what I call propellers, in fact, according to your theory, do not have propellers because that device that propels them does not work in an incompressible fluid (they are not rotating foils operating on a fluid that can be considered incompressible within limits). One always learn something new and I, fortunately, am still of learning age.
     
  6. hoytedow
    Joined: Sep 2009
    Posts: 5,671
    Likes: 285, Points: 93, Legacy Rep: 2489
    Location: North of Cuba

    hoytedow Wood Butcher

    Boat propeller does operate in a mostly incompressible liquid fluid, whereas airplane propeller operates in a very compressible gaseous fluid. One assumes this thread was addressing the mechanics within the liquid fluid.
     
  7. hoytedow
    Joined: Sep 2009
    Posts: 5,671
    Likes: 285, Points: 93, Legacy Rep: 2489
    Location: North of Cuba

    hoytedow Wood Butcher

    Welcome, Tracie.
     
  8. jehardiman
    Joined: Aug 2004
    Posts: 2,803
    Likes: 365, Points: 83, Legacy Rep: 2040
    Location: Port Orchard, Washington, USA

    jehardiman Senior Member

    Welcome to the forums.
    Actually I think a much simpler way to state the difference is that a propeller is made to propel the vehicle and an impeller is made to pump the fluid through a guided passage. A Voith-Schneider is a propeller, as is a Kaplan propeller in a duct, but a pump jet has an impeller, as does a White-Gill thruster.
     
    gonzo likes this.
  9. Mr Efficiency
    Joined: Oct 2010
    Posts: 9,065
    Likes: 640, Points: 113, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

    Then there is the "compeller", which in some cases, doubles as "the wife" ! :eek:
     

  10. hoytedow
    Joined: Sep 2009
    Posts: 5,671
    Likes: 285, Points: 93, Legacy Rep: 2489
    Location: North of Cuba

    hoytedow Wood Butcher

    Or, as I call her, SWMBO.


    She who must be obeyed. :confused:
     
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.