MadSci Network: Physics

Re: Why are rocket exhaust areas broad ?

Date: Thu May 29 22:15:37 2003
Posted By: Dennis K. Van Gemert, Systems Engineer
Area of science: Physics
ID: 1053429699.Ph

Current rocket systems have nozzles with a fixed exhaust area.  Optimum 
expansion occurs when the exhaust pressure equals the ambient pressure.  
Since the nozzle is fixed in area, optimum expansion is fixed for a 
particular altitude.  Therefore, upon ignition, the exhaust plume has a 
visible tail.  As the rocket reaches increasing altitudes, the tail widens 
and eventually disappears.  Once the plume passes optimum expansion 
(nozzle exit pressure equals ambient pressure), the plume widens beyond 
the diameter of the nozzle.  Once the rocket leaves the atmosphere, the 
plume seems to disappear, as the ambient pressure drops to near zero.


Current Queue | Current Queue for Physics | Physics archives

Try the links in the MadSci Library for more information on Physics.

MadSci Home | Information | Search | Random Knowledge Generator | MadSci Archives | Mad Library | MAD Labs | MAD FAQs | Ask a ? | Join Us! | Help Support MadSci

MadSci Network,
© 1995-2003. All rights reserved.