Steam turbines have two cycles: non-condensing and condensing ... Combustion increases the temperature, velocity and volume of the gas flow, which is forced through a nozzle over the turbine’s blades.

In a steam turbine, high-enthalpy (high pressure and temperature) steam is expanded in the nozzles (stationary blades) where the kinetic energy is increased at the expense of pressure energy (increase ...

Steam turbines have helped drive a large chunk of ... as well as the lack of a converging/diverging nozzle on the input of the turbine are likely big contributing factors to the low efficiency.