This was a very helpful video. Thank you. However, between points 4 and when you added 20 degrees celcius should you have not converted the 20 deg.C to Kelvin. Therefore 20 deg.C would be 293K making point 5 temperature about 723K?
You actually need to convert 431.161(k) to Deg.C, then sum 20 and convert back to kelvin, you'll notice that its the same as summing 20 Deg.C to the original 431.161 kelvin
I appreciate this video very much as it has helped me do a project for a class in Thermo System Design. I do have a question, however. The assumption that the Turbine pressure ratio is the same as the compressor leads to a Nozzle Pressure Ratio of 1. In this project that I am working on, there was no explicit information about the turbine pressure ratio, so I agree that from all my research online which only talks about the compressor, that the turbine ratio would be the same. However, if the nozzle is meant to have a NOT constant pressure heat rejection (providing the thrust) than this seems to be a dilemma as the pressure ratio is an exact 1 under this shared-compressor-ratio assumption. The "splitting the load" explanation i completely agree with, but it causes this problem to occur. Are low nozzle pressure ratio's actually an acceptable thing in design?
No - generally speaking, the turbine in a thrust-producing cycle (like the turbojet you’re describing) is only producing as much work as it takes to power the compressor (and maybe an alternator or refrigeration system). If you know how much work the compressor will take to hit a target combustion temperature and pressure, you set the work of the turbine equal to that and solve for your turbine outlet conditions. In that situation, the compression ratios should not be equivalent between the compressor and turbine, the specific work should be (as net work is no longer the goal).
@@Thermofluids I genuinely appreciate the quick reply. This definitely helped me understand it a bit more. I suppose the reasons for why the non-specific work value as I was obtaining were different, was due to considering a slightly higher mass flow entering the turbine due to combustion fuel. So this clears up one of those issues I was having. If I have any other questions I’ll comment again, nonetheless I appreciate the help you’ve already provided. It’s also helping out a few other people as well, as I am currently working with others on this thermo project
