1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Exhaust Velocity Calculation

  1. Mar 3, 2009 #1
    Please check my calculations for the exhaust velocity of a rocket that uses Nitrogen Tetroxide (N2H4) & Aerozine 50 as its propelants. This is the formula that I'm using to find out the exhaust velocity:

    V_e = \sqrt{{\frac{T*R}{M}}*{\frac{2*k}{k-1}}*[1-(P_e/P)^(^k^-^1^)^/^k] }

    Ve = Exhaust velocity at nozzle exit, m/s
    T = absolute temperature of inlet gas, K
    R = Universal gas law constant = 8314.5 J/(kmol·K)
    M = the gas molecular mass, kg/kmol (also known as the molecular weight)
    k = cp / cv = isentropic expansion factor
    cp = specific heat of the gas at constant pressure
    cv = specific heat of the gas at constant volume
    Pe = absolute pressure of exhaust gas at nozzle exit, Pa
    P = absolute pressure of inlet gas, Pa

    T = 3110 Kelvin
    R = 8314.5
    M = 20.24
    k = 1.2314
    Pe = Pa = 1 atm
    P = 25 atm

    V_e = \sqrt{1,277,573.864 * 10.643 * 0.454}[/tex]

    V_e = \sqrt{6,173,137.26}

    Ve = 2,484.5799 meters per second

    Are this calculations correct or did I make a mistake? I got the equation and most of the data from these two sites: http://en.wikipedia.org/wiki/Rocket_engine_nozzles, http://www.braeunig.us/space/problem.htm#1.10, and http://www.braeunig.us/space/comb-NA.htm.
    Last edited by a moderator: Apr 24, 2017
  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