What’s the topping cycle - Brayton?Frank Whittle initially used a centrifugal compressor and a centrifugal turbine to extract power from the gas. This design has problems for aircraft propulsion from which the axial-flow design does not suffer, but the centrifugal turbine has the advantage that the portion of the rotor which is subjected to the highest temperature is not subjected to the highest stress. In consequence, there still exists a flyable Whittle-powered jet which was built during WWII - whereas the Me-262 engines reportedly were used up after 30 hours of flight time.
Is the centrifugal gas turbine design still viable for stationary applications, notwithstanding the decisive advantage axial-flow designs enjoy in the huge aircraft propulsion market?
My first power plant start up was any early combined cycle in 1977. The gas turbines (oversized jet engines)are GE rated at 60 MW each, which exhaust at 900 DEGF. This makes for some reasonably dry steam.
The advantage is that the blades of the gas turbine can withstand temperatures far hotter than steel boiler tubes starting the heat extraction delta from a gas flame temperature down to river water temperature.