turbine sans aubes

CONT: Bladeless turbine ... An assembly of plain metallic discs is mounted on a shaft, with narrow spaces between the discs. Geothermal fluid - hot water and/or steam - is admitted to the spaces between the discs at the periphery, and is directed to follow an inward spiral path towards a central exhaust port. The driving force is derived from frictional boundary layer drag between the fluid(s) and the disc surfaces. Such a machine would be very cheap to construct and to maintain: the discs could easily be dismantled, cleaned of chemical deposits and reassembled.