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!

Find the Mass Flow Rate Through the Nozzle

  1. Feb 18, 2013 #1
    1. The problem statement, all variables and given/known data
    Helium gas flows through a well-insulated nozzle at steady state. The temperature and the velocity at the inlet are 550°R and 150 ft/s, respectively. At the exit, the temperature is 400°R and the pressure is 40 lbf/in2. The area of the exit is 0.0085 ft2. Using the ideal gas model with k = 1.67, and neglecting potential energy effects, determine the mass flow rate in lb/s through the nozzle


    2. Relevant equations



    3. The attempt at a solution

    My initial response is to use:

    m' = ρvA

    but I'm not sure if this is how they want me to find the answer. My professor mentioned:

    Cp - Cc = R

    Is this referring to specific heats?

    My notes also say Cp is constant. What is this referring to? Likewise, what is the significance of the k=1.67?
     
  2. jcsd
  3. Feb 18, 2013 #2

    SteamKing

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    k is the ratio of specific heats of the gas:

    k = Cp/Cv
     
  4. Feb 18, 2013 #3
    What is the significance of giving me the ratio of the specific heats of the helium?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook