# Interpreting graphs from isentropic efficiency of a compressor lab

1. Feb 6, 2017

### MattH150197

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 = + (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 * where p23 is the pressure drop in the venturi from position 2 to 3
Isentropic efficiency = 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!

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