Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Newby de laval nozzle ?

  1. Apr 9, 2009 #1
    Newby de laval nozzle ???

    I am experimenting with de laval nozzles. I am trying to make a nozzle that operates at room temprature and moderatly low pressure.

    This is the equation I have found for calculating area of throat.

    At = (q / Pt) x SQRT[ (R' x Tt) / (M x k) ]

    At= area of throat
    q = gas flow rate
    Pt= pressure at throat
    R'= Universal gas constant x molecular weight
    Tt= Temp at throat
    M= gravity constant
    k= gas specific heat ratio

    How do I calculate the volocity of the gas that exits the throat? What is an ideal volocity,
    is it relative to the speed of the rocket? Is it possible to work the above equation and end up with a low and therefor ineffective volocity? Do I have to set my pressure and flow rate
    based on a target gas exit volocity?

    Thanks for your time
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted