The problem of finding the optimal waterjet propulsion pump for a hydrofoil of given configuration and displacement is examined from the point of view of least weight. Included in the propulsion pump study are the gear weight for matching the waterjet pump to the specified prime mover(s) and fuel weight for a specified range and speed. From the current waterjet pump designs, two competing design approaches were selected: 1) Multi-parallel double suction impeller centrifugal pump with up to ten impellers, and 2) Axial pump with an inducer impeller followed by axial stages when required by the pump head and net positive suction head. Because of the hydrofoil's drag to speed characteristics with its take off hump, the pump design problem requires an efficient reliable pump that meets the cavitation conditions at take off. Both designs satisfy these requirements. From the required flow rate and system losses each pump design is solved for size and weight with the choice of optimum pump being the lightest design for that particular set of overall system parameters. Each pump design is directly related to the cavitation condition at the take off point which is the design point. The value of Thoma's cavitation criterion is closely related to the pump selection. As the value decreases the selection of pump shifts from the centrifugal to the axial design. The actual selection for a given design point is a trade off between the pump, gear, and fuel weights where the centrifugal design has the heavier fuel and lighter gear weight.

  • Corporate Authors:

    Massachusetts Institute of Technology

    Department of Ocean Engineering, 77 Massachusetts Avenue
    Cambridge, MA  United States  02139
  • Authors:
    • Percival, R C
  • Publication Date: 1972-6

Subject/Index Terms

Filing Info

  • Accession Number: 00044172
  • Record Type: Publication
  • Source Agency: Massachusetts Institute of Technology
  • Files: TRIS
  • Created Date: May 11 1973 12:00AM