I have a personal project to design a gas turbine engine, the main problem that puzzles me is how do I determine the pressure rise in each stage of an axial compressor?

Say, I'm planning on a 38:1 engine so how do I determine how many stages I might need and how much will be the pressure rise?

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    $\begingroup$ Are we super sure this is not class work? Sounds like class work. How did you select 38:1? What is the application? $\endgroup$ – acpilot Jun 24 '20 at 17:42
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    $\begingroup$ Just multiply the compression ratio of each stage. It's not so hard – the hard part is achieving those compression ratios at each stage. $\endgroup$ – Peter Kämpf Jun 24 '20 at 18:11
  • $\begingroup$ @PeterKämpf I think the OP has a total compression ratio and is looking to divide it by the number of compressor in the engine to determine pressure rise/compressor. As a matter of fact, that may just be the answer he's looking for... $\endgroup$ – FreeMan Jun 24 '20 at 18:35
  • $\begingroup$ @FreeMan: I know, and all he needs now is a realistic stage compression ratio. But he should now do a bit research himself. $\endgroup$ – Peter Kämpf Jun 24 '20 at 18:52
  • $\begingroup$ @acpilot: Couldn't agree more. With 38:1 the T4 will be too high for some amateur engine. You need mono crystalline blades with film cooling – impossible to do in a personal project. $\endgroup$ – Peter Kämpf Jun 24 '20 at 18:55

You'll have to look up what the technology level can bring you these days. Usually, cycle design is s joint effort of what is needed and what can be done. Engine manufacturers have an aerodynamic department that is in close contact with the engine cylce designers and marketing.

An OPR (overall pressure ratio) of a design is based on the maximum turbine inlet temperature and depending on the cooling technology. Once selected, the aerodynamacists will tell you how many stages you're going to need. Since you're not a manufacturer, you'll need to choose a value, 1.2 : 1 is a value you can use. Note that a turbofan has a higher stage pressure ratio.


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