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Homework Help: Interpreting graphs from isentropic efficiency of a compressor lab

  1. Feb 6, 2017 #1
    1. The problem statement, all variables and given/known data
    We did a lab experiment for isentropic efficiency of a compressor and was asked to plot the following graphs, change in stagnation pressure across the compressor (∆p0) vs air mass flow rate, and isentropic efficiency vs air mass flow rate. I have plotted the graphs but not sure what they actually represen

    2. Relevant equations
    change in stagnation pressure = upload_2017-2-6_21-0-44.gif + (ρH2O*g*(h1 - 1/4*(h2+h3+h4+h5))) where m air is air mass flow rate, A3 is area of venture position no.3 and h represents the heights of the manometer tubes.

    Air mass flow rate = A3 * upload_2017-2-6_21-4-57.gif where p23 is the pressure drop in the venturi from position 2 to 3
    Isentropic efficiency = upload_2017-2-6_21-16-40.gif where Tqs is the compressor shaft torque and w is the compressor shaft speed

    3. The attempt at a solution
    In the image attachment it shows the excel spreadsheet I used to compute these calculations I then put those calculations into a graph which I have also attached but like I said im not sure what the graphs are actually supposed to represent. Thanks for any help you can offer!

    Attached Files:

  2. jcsd
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