Why does an FT8 turbine have a twin rotor?
The FT8 training course kicked off today, and there has been a great response from all. I did get a query as to the reasoning behind the two-rotor design.
You will never see a twin rotor design such as the FT8 on an industrial turbine, as it is too ?expensive to manufacture and to maintain, but for aircraft applications the cost is outweighed by the power to weight ratio of the turbine.
In a twin rotor design the Low Pressure Rotor passes through the hollow High Pressure Rotor shaft. Therefore, the rotors can rotate independently of each other.
However, as the temperature of the air increases, the velocity point where the choke occurs also increases.
Now consider that the air temperature leaving the High-Pressure rotor is more than 400F. The High-Pressure rotor can therefore process higher velocity air than the Low-Pressure rotor. For this reason, the High-Pressure rotor turns more than 11,000 RPM while the Low-Pressure rotor turns at speeds of approximately 7,000 RPM. Higher speeds mean you can process more air for combustion, and therefore potentially more power.
#FT8Training #FT8 #DonMurphy
CEO / Providing Energy Solutions, where and when needed
5 个月Awesome work, some think knowledge is power, but educating and helping others is truly empowering
Electrical Field Engineer / MAINTENANCE / GMAO / R&D Electrical Engineer / Electrical Power/ PhD / MATLAB / MVF / Superconductor application in electrical engineering / SFCL
5 个月Thank you very much Donald Murphy
Freelancer
5 个月In the years when the turbine model derived from aviation FT8 gas turbine was used, the vsv mechanism was not yet known. In those years, the only known bleed valve system for chocking control was the bleed valve system and these turbines had two bleed valves with a diameter of 4.5 inches and 6 inches. However, the only known solution to provide 'stall margin' control at low rpm was using double compressors N1 and N2.