This study investigates analytically a concept for accelerating liquid slugs to high velocities by the use of supersonic gas nozzles. This technique is of interest for developing economic methods for cutting rock during tunnel construction. The merits of this concept are based on the fact that only moderate gas pressures are required to accelerate liquid slugs to velocities which have been demonstrated as suitable for fracturing rock material. To obtain these velocities by liquid nozzles alone, very high hydraulic pressures would be required. This concept, therefore, amplifies the pressure which is used to accelerate the slug to a high value delivered to the face of the rock material. The concept for mechanizing this augmentation is a hypervelocity gun comprising of a constant area section tube for accelerating the slug to sonic speed and a diverging area tube for further accelerating the slug to supersonic gas speeds. Analyses are performed to evaluate the lengths and acceleration times for both sections of the gun under different conditions of supply pressure and temperature and slug sizes. An important aspect of this concept is the requirement to control the hypervelocity jet driver repetitively at a controlled frequency and slug size. The design considerations for such a jet driver control system are considered and a preliminary concept is presented. (Author)

  • Supplemental Notes:
    • See also PB-178 437.
  • Corporate Authors:

    Bowles Engineering Corporation

    Silver Spring, MD  United States 
  • Authors:
    • Neradka, V
    • Walston, W
    • Turek, R
  • Publication Date: 1968-5

Media Info

  • Pagination: 87 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00039040
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: BEC-R-22-68 Final Rpt
  • Contract Numbers: 3-0055ct
  • Files: TRIS
  • Created Date: Nov 24 1973 12:00AM