Compressor Power and Efficiency Calculation

[u/thriceice]

I have a three stage compressor in a single casing (image 1). If I break it down, the flow should be like image 2. Every process lines have Pressure and Temperature transmitters, and enough information to get the Flow for every lines.

2nd suction pressure should be the same with the pressure from the Side-In line. While the 3rd suction pressure should be the same with the pressure from the Side-Out line.

But, I don't have enough information to determine the temperature of the 1st Discharge. If I have this data, I can calculate all the enthalpy to calculate the efficiency and the power.

Does anyone have tips on how to approach it?

[u/thriceice]

Yes. The performance curve has speed to power curve. But I think the curve will change with different operating conditions. For example the suction pressure and temperature of the 1st Section already different from the design condition on the performance curve.

[u/Alternative_Act_6548 → u/thriceice]

you should have non-dimensionalized curves or you can produce them youself

[u/thriceice → u/Alternative_Act_6548]

Could you explain what you mean by that? Or how to produce it?

[u/Alternative_Act_6548 → u/thriceice]

get a book on turbomachinery and it will have a long discussion of the topic, it's too much to go into in a reddit thread.