ps; I'm so used to my old textbooks that sometimes I forget there's google! ...lol...
Which I just tried...and found that anyone who wants to be sure of their facts can do so in less than 5 seconds.
A google of "centrifugal turbine expander heat engine", and variations on those terms, instantly provided the following facts; among thousands of others.....
(underlines are mine)
Brayton cycle: Definition from Answers.com
1791 - John Barber received the first patent for
a heat engine in which a bellows (compressor) and
a turbine (expander) were connected...
www.answers.com/topic/brayton-cycle
Heat engine - Patent 6336316
6134876, Gas turbine engine with exhaust expander and compressor, Hines et al. ..... 4 comprises, as an example,
a centrifugal turbine T 32 ,
(turbo-turbines are heat-engine turboexpanders)
"Elliott Company • Products • Steam Turbines/Expanders
The TH power recovery expander turbine is available to utilize the energy in
high temperature,
low pressure gas streams to drive..."
http://en.wikipedia.org/wiki/Steam_turbine
A steam turbine is a mechanical device that extracts
thermal energy from pressurized steam, and converts it into useful mechanical work.
(it's the heat, not the pressure, producing the majority of the shaft-power)
etc. etc..