Plug nozzle
The plug nozzle is a type of nozzle which includes a centerbody or plug around which the working fluid flows. Plug nozzles have applications in aircraft, rockets, and numerous other fluid flow devices.
Hoses
Common garden hose trigger nozzles are a simple example of the plug nozzle and its method of operation. In this example the nozzle consists of a conical or bell shaped opening with a plug on a movable rod positioned in front of the nozzle. The plug looks similar to a poppet valve. The stem of the valve runs back through the body of the nozzle body to a "trigger", normally a long lever running down the back of the nozzle assembly. A spring keeps the valve pressed against the opening under normal use, thereby providing a failsafe cut-off that stops the flow of water when the nozzle is dropped.
When water is supplied to the hose, it flows through the nozzle body to the opening, where it would normally flow straight forward in a stream. Just after leaving the opening it encounters the plug, which deflects the water sideways through an angle. After travelling a short distance the water encounters the outside of the nozzle opening, which deflects it forward again. This two-step process causes the water to be ejected in a ring-shaped pattern, which causes less water to strike any one location, and thereby reduces erosion while also making it easier to water larger areas.
The shaping of the plug and the nozzle opening allows the angle of the ring to be adjusted. Normally this is shaped so that when the plug is pulled back toward the opening it both partially cuts off the water flow, as well as causing it to spread out to the widest possible angle. This can be used for "misting" plants. When the trigger is pushed down further, the plug moves away from the opening, causing less blockage and disruption of the flow, ultimately allowing the water to form back into a stream.
In rockets
Plug nozzles belong to a class of altitude compensating nozzles, much like the aerospike, which, unlike traditional designs, maintains its efficiency at a wide range of altitudes.[1]
Similar to the garden hose example, plug nozzles use a shaped
Confusingly, the term "plug nozzle" may also be used to refer to an entirely different class of engine nozzles, the aerospikes. In theory the aerospike should look roughly like a
In aircraft and missiles
The jet-engine plug nozzle has its origins in rocketry
Propelling nozzles for subsonic aircraft have used a center-body/bullet/cone to give the nozzle exit area required to set an axial compressor running-line correctly on its map. The first operational German turbojet engines with axial compressors, the
See also
Further reading
- Aerospike Engine, Jeff Scott, Fall 1999. This paper gives an extensive review of the various altitude compensating nozzle designs.
References
- ^ O'Leary, R.A.; Beck, J. E. (Spring 1992). "Nozzle Design". Threshold. Pratt & Whitney Rocketdyne. Archived from the original on 2010-04-02.
- ^ Aukerman, Carl A. (August 1, 1991). "Plug nozzles: The ultimate customer driven propulsion system". Archived from the original on October 5, 2021. Retrieved July 25, 2018 – via ntrs.nasa.gov.
- ^ Stitt, Leonard E. (May 1, 1990). "Exhaust Nozzles for Propulsion Systems with Emphasis on Supersonic Cruise Aircraft". ntrs.nasa.gov. p. 31. Archived from the original on October 5, 2021. Retrieved July 25, 2018.
- ^ "Archived copy". Archived from the original on 2018-07-26. Retrieved 2018-07-25.
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: CS1 maint: archived copy as title (link) - ISBN 978-1-60086-711-8, p.276
- ISBN 978-0-7643-4894-5, p.188
- ^ Stitt, Leonard E. (May 1990). "Exhaust Nozzles for Propulsion Systems With Emphasis on Supersonic Cruise Aircraft" (PDF). Reference Publication 1235. NASA. Archived (PDF) from the original on 17 May 2010. Retrieved 14 July 2012. (42.1 Mb)
- ^ "Archived copy" (PDF). Archived from the original (PDF) on 2015-10-01. Retrieved 2018-07-25.
{{cite web}}
: CS1 maint: archived copy as title (link) - ^ A Case Study By Aerospatiale And British Aerospace On The Concorde, Rech and Leyman, AIAA Professional Study Series, p. 6-10
- ^ Journal of Sound and Vibration Volume 206, Issue 2, 18 September 1997, Pages 169–194.
- ^ Jet Propulsion Progress, First edition, Neville and Silsbee, McGraw-Hill Book company, Inc. New York and London, 1948