THRUSTING CHARACTERISTICS OF PROPULSORS

The function of any propulsive system, is to provide a forward thrust along its axis. The design objective is to obtain a maximum in propulsor thrust with a minimum of shaft power while satisfying practical limits of propulsor size, shaft speed, and cavitation resistance. The generation of thrust requires that some kinetic energy be lost in the propulsive slipstream. These losses are associated with both axial and rotational velocity components in the slipstream. In addition, the presence of rotational velocity in the slipstream results in a low pressure region in the far wake which reduces the net effective thrust generated by the propulsor. It has been the tradition of the propulsor designer to neglect the rotational effects, other than considering the kinetic energy losses, since it is assumed that the rotational component of velocity in the far wake is small. This assumption is valid for propulsors that ingest large mass flows and place a small amount of energy per unit mass in the flow. However, the trend now is toward more heavily loaded propulsors, both of the open or ducted type. Thus, a reevaluation of the relative magnitudes of the losses associated with the velocity components in the propulsive slipstream is necessary. It is the intent of this paper to evaluate, for a given shaft power, the relative losses in propulsor thrust associated with the axial and rotational velocity components in the slipstream.

  • Corporate Authors:

    Pennsylvania State University, University Park

    Applied Research Laboratory
    University Park, PA  USA  16802
  • Authors:
    • Gearhart, W S
    • Bruce, E P
  • Publication Date: 1980-5-30

Media Info

  • Pagination: 33 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00325842
  • Record Type: Publication
  • Report/Paper Numbers: ARL/PSU/TM-80-118
  • Contract Numbers: N00024-79-C-6043
  • Files: TRIS
  • Created Date: Mar 12 1981 12:00AM